United States      Solid Waste and      EPA530-R-99-020h
Environmental Protection   Emergency Response     NTIS: PB99-155 897
Agency       	 (5305W)   	   April 1998 	
Response to Comments
Document:  Land Disposal
Restrictions-Phase IV Final
Rule Promulgating Treatment
Standards for Metal Wastes;
Mineral Processing Secondary
Materials and Bevill Exclusion
Issues; Treatment Standards
for Hazardous Soils; and
Exclusion of Recycled Wood
Preserving Wastewaters;
Volume 8: Comments Related to
Regulatory Impact Analysis for Newly
Identified Mineral Processing Waste
Issues Raised in First Supplemental
Proposed Rule (January 25, 1996)
      Printed on paper that contains at least 30 percent postconsumer fiber

T,iĞt nf f^fimmpn^ffs
Roderick T. Dwyer, Deputy General Counsel, National Mining Association
Michael V. Ruby, Senior Environmental Chemist, PTI Environmental Services
Edward J. Kinghorn, Jr. , President, The Ferroalloys Association
Gary F. Lindgren, CHMM, Vice President, Environmental Compliance, Heritage Environmental
Services, Inc.
Christopher H. Marraro and William F. Hughes, Attorneys for Marine Shale Processors, Inc..
Howrey & Simon
Raymond F. Pelletier, Director, Office of Environmental Policy and Assistance Department of
Alan R. Wood, Manager Waste Management Section Environmental Services, American
Electric Power
Scott Davis, Environmental Department Leader, Arizona Public Service Company
Thomas J. Dammrich, President, Institute for Interconnecting and Packaging Electronic Circuits
Edwin H. Seeger, Attorney for Lead Industries Association, Inc., Seeger, Potter, Richardson,
Luxton, Joselow & Broods, L.L.P.
David Sterman, Deputy Commissioner, New York State Department of Environmental
Denise Lee, Anson County CACTUS, Chapter of the Blue Ridge Environmental Defense
Tim Scott, Vice President of Operations, Avocet Tungsten, Inc.
Steve Baumann, General Manager, Chemgold, Inc.
Frederick J. Koehler, Senior Staff Engineer, General Motors Corporation North American
Operations Worldwide Facilities Group
Public Service Electric and Gas Company
Chemical Waste Management, Inc.
David W. Aument, Safety, Health, and Environmental Affairs Manager, DuPont White Pigment
and Mineral Products
Westinghouse Electric Corporation
Arthur Beckerman, Senior Environmental Engineer, US Borax, Inc.
Paul W. Rankin, President, Association of Container Reconditioners
Dr. Donald E. Knapp, SCM Chemicals, Inc.
Don Vidrine, Manager Hazardous Waste Program, Montana Department of Environmental
Quality Waste Management Division Hazardous Waste Program
Raymond E. Krauss, Environmental Manager, Homestake Mining Company McLaughlin Mine
Terry S. Casey, KRONOS, Inc.
Colin Sweeney, CHMM Manager Site Remediation, Jersey Central Power & Light Company
L.S. Magelssen, Assistant Director of Environmental Affairs, Union Carbide Corporation
Shirley M. Ruffm, Environmental Services Department, South Carolina Electric and Gas
Alan Dahlstrand, General Manager, Sonora Mining Corporation
Kevin J. Igli, Vice President Environmental Management, Chemical Waste Management, Inc.
Laidlaw Environmental Services, Inc.
James M. Gerek, Unit Director Environmental Issues, Kodak
Walter D. Ramsay, International Precious Metals Institute

I Jst of ("'nmmpntpi-s
Robin K. Wiener, Assistant Counsel/Director of Environmental Compliance, Institute of Scrap
Recycling Industries, Inc.
John L. Wittenborn and Chet M. Thompson, Counsel to the Metals Industries Recycling
Coalition, Collier, Shannon, Rill & Scott
Krishna Parameswaran, ASARCO
Sierra Club's Midwest Office and the Mining Impact Coalition of Wisconsin, Inc.
Phelps Dodge Corporation
Solite Corporation
Kennecott Corporation
David J. Lennett, Counsel to Environmental Defense Fund, Law Office of David J. Lennett
Joseph H. Baird, Phosphorus Producers Environmental Council
Steven G. Barringer, Attorney for Precious Metals Producers, Battle Mountain Gold Company,
Barrick Gold Corporation, Echo Bay Mines, Independence Mining Company, and Santa Fe
Pacific Gold Corporation, Singer & Brown
Jean Beaudoin, Chairman BCI Environmental Committee and Gerald Dubinski, Chairman BCI
Industry Relations Committee, Battery Council International
The Fertilizer Institute
Cyprus Amax Minerals Company
Basil G. Constantelos, Vice President Environmental Policy and Governmental Relations,
Safety-Kleen Corp.
Guy D. Van Doren, Vice President, LAN Associates, Inc. on behalf of SKW Metals & Alloys,
Robert Hogfoss, Hunton & Williams on behalf of Kemira Pigments, Inc.
Michael J. Fitzgerald, Nugent, Fitzgerald, McGroarty & McFadden on behalf of New Jersey
Natural Gas Company
Michael J. Fitzgerald, Nugent, Fitzgerald, McGroarty & McFadden on behalf of South Jersey
Gas Company
Robert Lucht, Mining Engineer and Geologist
INCO LTD., INCO United States, Inc., and International Metals Reclamation Company, Inc.
Gerald A. Dumas, Vice President Environmental Services, RSR Corporation
Joseph L. Mayer, Copper & Brass Fabricators Council, Inc.
Utility Solid Waste Activities Group, Edison Electric Institute, American Public Power
Association, and National Rural Electric Cooperative Association
John K. Mudge, Director Environmental Affairs, Newmont Gold Company
Richard L. Lawson, President, National Mining Association
Critique of EPA's LDR Phase IV LDR Supplemental Rule, National Mining Association
An Analysis and Critique of the Environmental Protection Agency's "Regulatory Impact
Analysis of the Supplemental Rule Applying Phase IV Land Disposal Restrictions to Newly
Identified Mineral Processing Wastes, National Mining Association
Review of Technical Documentation Provided by US EPA in n Support of the Supplemental
Proposed Rule on Land Disposal Restrictions, National Mining Association
Comments Regarding Use of the Toxicity Characteristic Leaching Procedure to Analyze Minera
Processing Wastes, National Mining Association
John Otto, Brush Wellman, Inc., Brian Buck, JBR Environmental Consultants, and Ronald R.
Janke, Jones, Day, Reavis & Pogue, Brush Wellman, Inc.

List of C!nmrppntprs
Brian Buck, JBR Environmental Consultants and Ronald R. Janke, Jones, Day, Reavis & Pogue
Brush Wellman, Inc.
Brian Buck, JBR Environmental Consultants and Ronald R. Janke, Jones, Day, Reavis & Pogue
Brush Wellman, Inc.
Marc E. Kolanz, Brush Wellman, Inc. and Ronald R. Janke, Jones, Day, Reavis & Pogue, Brush
Marc E. Kolanz, Brush Wellman, Inc. and Ronald R. Janke, Jones, Day, Reavis & Pogue, Brush
Robert J. Bayer, Chairman Environment Committee, Utah Mining Association
Gary Crouth, Manager Solid & Hazardous Waste, Alcoa EHS Department, Aluminum Compam
of America
Bill Ferdinand, Radiation Safety, Licensing & Regulatory Compliance, Rio Algom Mining Corp
BHP Copper
Gene Dewey, President, Molycorp, Inc.
David Shoemaker, Manager Molybdenum Operations, Molycorp, Inc.
Peter Walsh, Assistant Deputy Under Secretary of Defense, Office of the Under Secretary of
Mark S. Pelizza, Vice President Health, Safety and Environmental Affairs, Uranium Resources,
Copper Range Company
Willie Taylor, Director Office of Environmental Policy and Compliance, US Department of
Allan Silber, Chairman, Recyclers of Copper Alloy Products, Inc.
John Stauter, Vice President, Kerr-McGee Corporation
Barry Meyer, Vice President Governmental Affairs and Associate General Counsel, The
Aluminum Association
Robert Briggs, Director of Manufacturing, Rhone-Poulenc
Stuart Sanderson, President, The Colorado Mining Association
Randall Jones, Director Regulatory Affairs, Molten Metal Technology
Barry Christensen, Manager of Solid Waste, OxyChem
John Moore, Akin, Gump, Strauss, Hauer & Feld, Attorneys for Horsehead Resource
Development Company, Inc.
Electronics Industries Association
Eric Males, Director Solid Waste Issues Regulatory Affairs, Chemical Manufacturers
Michael Doyle, President, Nevada Mining Association
Gerald Pepper, Environmental Affairs Manager, US Borax
William Williams, Director Health Safety and Environmental Quality, Kennecott
Denise Jones, Executive Director, California Mining Association
Russell Rhoades, Director, Arizona Department of Environmental Quality
Michael Baly III, President and Chief Executive Officer, American Gas Association
Douglas M. MacMillan, Executive Director, Environmental Technology Council
Jack L. Craven, Acting Director of Minerals & Geology Management, US Department of

Tyist of Pnmmpntprs
Edward J. Kinghorn, Jr., President, The Ferroalloys Association
Association of Battery Recyclers, Inc.
Debra Beaver, Chair NPRC Hard Rock Mining Task Force, Northern Plains Resource Council
Gary Beach, Administrator Water Quality Division, State of Wyoming Department of
Environmental Qualify

                                     Table of Contents

 1.      Adequacy of the Regulatory Impact Analysis (RIA)	  1
2.      Proposed Regulatory Requirements and Predicted Responses	  3
        2.1     Perceived Errors in the Description of the Two Regulatory Options  	  3
        2.2     Potential Decreases in Recycling of Mineral Processing Secondary Materials	  4
        2.3     The Remining Assumption 	  6
3.      Cost Analysis	  8
        3.1     General	  8
        3.2     Multipliers  	  8
        3.3     Rounding  	  9
        3.4     Waste Generation Rates and Facility Averages	  9
        3.5     Cost Functions	  10
        3.6     Calculations 	  11
        3.7     Assumptions	  12
4.      Specific Mineral Processing Sectors and Facilities	  13
5.      Risk Assessment  	  16
        5.1     General	  16
        5.2     Hazard Assessment	  16
        5.3     Exposure Assessment	  18
        5.4     Scope of the Risk Assessment	 21
        5.5     Data Quality/Availability	21
        5.6     Risk Management	22
        5.7     Documentation	 22
6.      Other Comments (UIC Comments)	22

 1.      Adequacy of the Regulatory Impact Analysis (RIA)

        Comment:  Two commenters argued that the RIA did not adequately assess the economic impacts of
 the proposed rule because the costs and benefits associated with the proposed rule were based largely upon
 assumptions. (COMM57, COMM85) One commenter specifically mentioned that EPA does not have strong
 confidence in the estimates of the quantity of wastes generated that will have to be treated to UTS standards
 or in the contaminants that will have to be treated.  This commenter believed the costs of the proposed rule
 were underestimated as a result. (COMM85)
        Response: EPA disagrees with these comments for two reasons. First, assumptions and uncertainty
 do not necessarily imply an underestimate any more than an overestimate. EPA simply attempted to quantify
 the level of confidence in the input data and results.  Second, these estimates were used to develop an estimate
 of the total impact on the affected industry, and not to create a detailed cost estimate for any specific facility.
 The use of assumptions does not mean that the economic impacts of the proposal were not adequately
 addressed. Rather, it was precisely because of EPA's desire to accurately estimate impacts on the regulated
 community that the necessary assumptions were developed, employed, and documented.

        Comment: One commenter stated that the analysis of the proposed rule presented in the RIA was
 inconsistent with prior EPA interpretation and the jurisdictional limits on EPA's authority under RCRA.  The
 commenter felt that the RIA must be corrected based on this assertion, but did not provide any specific detail
 on this issue. (COMM39)
        Response: EPA disagrees with the comment but is unable to respond specifically to the commenters
 underlying concerns because the comment did not include supporting detail.
        Comment: Another commenter contended that EPA failed to provide an opportunity for comment
 on its evaluation of the economic impact and benefits of the proposed rule.  The commenter argued that the
 evaluation of the economic impact of the proposed rule was deficient and it precluded comment because (1)
 EPA had not pulled the relevant information together and performed a complete analysis of the rule, and (2)
 EPA failed to provide the necessary details and support materials to allow for review by the public.

        Response: EPA used all available data to assess the impacts of the rule. Where data were not
 available, the Agency used conservative estimating  procedures to determine the costs and benefits of this
rulemaking.  The underlying data can be found in the Identification and Description of Mineral Processing
Sectors and Waste Streams Technical Background Document, EPA, 1995 (Identification Background
 Document), and a description of the procedures used to estimate the impact of the rule can be found in the
December 1995 RIA.  EPA also solicited additional data on a number of issues in the preamble to the
proposed rule.  EPA has incorporated the data provided in public comment into the revised  and final RIAs.
Further, in addition to the background materials included in the docket at the start of the comment period, the
Agency provided additional documents for public review at the request of interested parties and extended the
duration of the public comment period to allow for public review of and comment on these additional
supporting materials.
        Comment: One commenter argued that EPA has not evaluated the alternative of not regulating (i.e.
the status quo) in its analysis of the proposed rule. (COMM58)
        Response: EPA disagrees with the commenter.  Option 2 of the December 1995 RIA reflects the
status quo regarding the definition of solid waste and mineral  processing secondary materials. Regarding the
promulgation of treatment standards for the wasted portion of these materials, promulgation of LDR
standards for the subject wastes is required by the HSWA amendments to the RCRA statute (as noted in the
Chapter 1 of the RIA). EPA  has proposed these standards pursuant to a consent decree in which the Agency

has explicitly recognized this directive from the U.S. Congress. The status quo option would not fulfill
EPA's obligations.
        Comment: Two commenters contended that the scope of the RIA was narrower than the scope of
the proposed rule in that the RIA only evaluated impacts associated with waste streams which were (1)
treated and land disposed; (2) stored in land-based units prior to reinsertion into a mineral process unit; and
(3) co-processed with virgin ores in land-based mineral beneficiation units.  The commenters argued that the
proposed rule also appears to be applicable to other land-based activities, non land-based activities, and
actual production units. The commenters felt that the RIA underestimated the impact of the proposed rule as
a result. (COMM58B, COMM67)
        Response:  It is not the Agency's intention to regulate "other land-based activities, non land-based
activities, and actual production units." Nor does the final rule do so. Thus, mineral processing secondary
materials may be placed in land-based process units (such as heap leach piles), and the production unit would
not be subject to regulation.
        Comment: One  commenter asserted that the Identification Background Document's
characterizations of various materials as spent materials, sludges, and by-products were technically and
factually inaccurate, particularly when used as a basis for the RIA. The commenter did not provide any
specific detail on this issue. (COMM67)
        Response:  EPA  has used the best information available  to classify secondary materials as spent
materials, sludges, and byproducts.  As new information became available, the Agency reevaluated these
classifications and revised them as appropriate.  Since the commenter has not provided any examples of
inaccurate classifications, EPA cannot address the commenter's specific concerns.
        Comment: One  commenter argued that the environmental benefits projected by EPA for the
proposed rule are speculative and overstated. The commenter disputed the assumptions that the proposed
rule will increase recycling of secondary materials, or reduce the risks associated with secondary materials
which have caused environmental and human health impacts in the past. (COMM38)
        Response:  EPA  believes that the health benefits associated with the mineral processing LDRs have
been reasonably estimated and that the methods used to estimate benefits are adequately documented in the
revised RIA. It is important to note that the health benefits of the various regulatory options do not result
only from increased recycling. In fact, as discussed in the revised RIA, all of the quantified health and
environmental benefits come from improvements in the disposal practices for unrecycled materials and from
improvements in storagejcontrols on materials that are currently recycled and which will continue to be
recycled under LDRs.
        Comment: Another commenter asserted that the benefits analysis presented in the RIA was
inadequate and based upon insufficient information. (COMM57)
        Response:  The RIA discussed in detail the limitations of the data used  to develop regulatory
benefits estimates.  EPA believes that the data are sufficient to support the benefits estimates that have been
developed (even though estimates for some wastes streams with little data may be quite uncertain).  EPA also
believes that the lack of data for some wastes streams has, if anything, resulted in an underestimation of
benefits from the proposed LDRs for the no prior treatment baseline analyzed.
        Comment: One commenter stated that the benefits analysis failed to account for existing state
regulatory regimes that already regulate environmental impacts from land-based units. The commenter
indicated that the State of Nevada, for example, imposes a variety of requirements which ensure that the
environment is protected even when production operations take place in land-based units.  The commenter
felt that the proposed rule will only complicate matters by requiring facility operators  to comply with dual
regulatory schemes. (COMM57)

        Response: EPA agrees with the commenter. One limitation of the analysis is the absence of state
environmental regulation of mineral processing operations affected by this proposal.  EPA notes that the
presence of state environmental regulation has the potential to decrease both incremental costs and benefits
associated with this proposed rule. EPA will try to assess the effect of state environmental regulation to the
extent possible in future regulatory impact analyses for the Phase IV LDR final rule.  EPA will identify any
uncertainty regarding the effect of state environmental regulation in future analyses.
        Comment:  One commenter stressed that EPA needs to quantify the benefits associated with the
proposed rule. This commenter also questioned whether the estimate of the benefits associated with the rule
takes into account the facilities that will close or discontinue processing co-products as a result of the rule.

        Response: EPA has quantified benefits to the extent feasible in the revised RIA. The quantified
benefits arise from changes in both waste disposal and  recycling practices. EPA's benefits analysis of health
and environmental benefits did not take into account any shifts in recycling or co-processing practices.

        Comment:  One commenter asserted that the benefits associated with the proposed rule are minimal,
as EPA mentions in the preamble to the proposed rule.  The commenter stated that the proposed  rule will not
"protect and improve the health, safety, environment, and well-being" of the American people, nor can it
improve "the performance of the economy without imposing unacceptable or unreasonable costs on society."
        Response: EPA believes that the proposed LDR would protect health and the environment both
through improvements in the treatment and disposal of unrecycled wastes, as well as through improvements
in the management practices for recycled materials;:—^specifically by eliminating or improving land-based
storage units for hazardous secondary materials which will be recycled.
        Comment:  The commenter indicated that the LDR benefits estimated by the RIA are primarily the
reduction in health risks arising from reduced human exposures to waste constituents in ground water. The
commenter also stated that the RIA's summary measure of this benefit is "changes in the number of facilities
disposing of various wastes (facility-waste stream combinations) at which the calculated risks exceed selected
levels."  The commenter argued that to the extent that the LDR results in an increase in the volume of newly-
identified materials treated and disposed, rather than recycled, the actual health risk improvement may be
significantly less than that estimated by the RIA.  (COMM58B)
        Response:  The final rule requires improvements both in the management of recycled secondary
materials and in the treatment and disposal of unrecycled materials. In either case,  materials must be
managed so that potential risks to the public health and the environment are limited. Thus, even  if, as the
commenter maintains, some materials move from being recycled to being disposed, the proposed LDRs
would require treatment prior to disposal to minimize health and environmental risks. In addition, the
commenter's implicit assumption that risks from recycling are less than risks from  treatment and disposal are
unsupported, particularly when the rule targets land-based units which tend to pose the same risks whether
used for disposal or whether used for storing hazardous secondary materials..

2.      Proposed Regulatory Requirements and Predicted Responses

        2.1     Perceived Errors in the Description of the Two Regulatory Options

        Comment: One commenter questioned EPA's description of how materials are recycled under
existing rules. The commenter referenced the conclusion of the RIA section of the preamble to the proposed
rule, where EPA recommended Option  1 (the proposed rule  approach) over Option 2 (status quo), because
Option 1 allows for a one year storage period as opposed to a 90-day storage period for Option 2. The

commenter added that it did not understand the reference to the 90-day storage period under Option 2
because, under existing rules, materials that are exempt from the definition of solid waste are not subject to a
90-day storage period. Rather, they are subject to the speculative accumulation criterion at 40 CFR §261.2.
The commenter stated that the 90-day storage period only applies to on-site storage of hazardous waste.
        Response: EPA notes that, under current regulations, hazardous::spent materials may only be stored
for 90 days before the generating facility would be considered a treatment, storage, and disposal facility,
requiring a RCRA Part B permit. (See 40 CFR §262.34.)
        Comment: Another commenter argued the following point:
               "The Phase IV LDR rules, if Option 2 is chosen, would not be subject to the LDR
        timing requirements in §3004 at all, because they would not be LDR rules. RCRA
        §§3004(h) and (m) refer to 'prohibitions' and 'treatment standards,' respectively.  The
        requirements  that are contemplated in Option 2 of the Phase IV proposed rule are neither
        one. The proposed requirements, addressing air  emissions, sludges, and leaks from CWA
        wastewater surface impoundments, would be neither prohibitions from land disposal under
        RCRA §3004(d) through (g), nor treatment standards pursuant to RCRA §3004(m).  If there
        is any authority in RCRA for such requirements, it does not come from the LDR provisions.
        The technical surface impoundment requirements in Option 2 of the Phase IV proposal are
        clearly not 'prohibitions,' because, as noted above, the hazardous wastes involved are
        already prohibited from land disposal. The proposed Option 2 requirements cannot be
        treatment standards, because they are not "levels" or 'methods' of treatment as set out in
        §3004(m) of  RCRA. The Option 2 requirements would not be prohibitions or treatment
        standards, and thus are not subject to the LDR timing requirements in RCRA §3004."
The commenter then noted in a footnote that:
                "If EPA believes that authority exists for the Option 2 requirements in some part of
        RCRA other than the LDR provisions, one remaining issue would be whether RCRA
        §3010(b) would require the regulations to be effective within six months of final
        promulgation of the rule. EPA has determined that it has the discretion to stay the effective
        date of RCRA rules where necessary (as with the Subpart CC rule, see 60 Fed.  Reg. 50,426
        Sept. 29, 1995).  If such a stay is not an option, however, EPA should delay final
        promulgation of the Phase IV LDR rule until after the HWIR rule is promulgated."
        Response: EPA believes that the commenter has mischaracterized Option 2 of the RJA. Option 2
does not pertain to air emissions, sludges, and leaks from CWA wastewater surface impoundments as the
commenter asserts. Option 2 models current regulatory requirements for mineral processing secondary
materials being recycled (i.e., spent materials being reclaimed are solid wastes whereas characteristic sludges
and by-products being reclaimed are not solid wastes). With respect to the wasted portion of mineral
processing secondary  materials, Option 2 models treatment to universal treatment standards established
pursuant to §3004(m) of the Resource Conservation and  Recovery Act.

        2.2    Potential Decreases in Recycling of Mineral Processing Secondary
        Comment: Seven commenters stated that the RIA was inadequate and underestimated the costs
associated with the proposed rule because the RIA failed  to account for the possibility that recycling of
mineral processing secondary materials may decrease with the promulgation of the proposed rule. The
commenters asserted that the imposition of a quantitative legitimacy test, Bevill mixture test, or toxics-ratio

test would serve to decrease recycling within the mineral processing industry, impose new treatment and
disposal costs, and have a negative economic impact upon the mineral processing industry.  Several of the
commenters argued that EPA's "static" assumption in the RIA was an incorrect one, and the economic costs
of the proposed rule should be evaluated on a "dynamic" basis to reflect decreases in recycling caused by
imposition of this rule. (COMM36, COMM46, COMM57, COMM58, COMM58B, COMM67, COMM85)
        Response:  The Agency has conducted a dynamic analysis for both the April 1997 RIA and the final
RIA, to account for both incentives and disincentives to recycling.
        Comment: Two commenters indicated that the most significant economic impact of the proposed
rule may arise from changes in industry practices with respect to newly-identified material recycling. The
commenters asserted that passing or failing a legitimacy test or Bevill mixture test could cause a change in a
mineral processing unit's ability to continue recycling a given material.  The commenters believed that the
possibility of decreased recycling needs to be examined to adequately portray the costs associated with the
proposed rule. (COMM58B, COMM67)

        Response:  The Agency has withdrawn the requirement for a quantitative legitimacy test from the
final rule.
        Comment: One of the commenters contended that the impact of changes in industry practices could
be large, and for a processing unit currently recycling newly identified materials, failing the tests would force
the facility operator to either:  1) stop the recycling activity, or 2) risk losing the Bevill exemption for the
entire unit and be effectively classified as a hazardous waste disposal unit subject to RCRA Subtitle C
        The commenter added that if the processing unit decides  to stop recycling the materials, the economic
effects could include the following:  1) lost revenue from sale of the metal values contained in the material, 2)
added costs for treating and disposing of the material, and 3) added cost to purchase commercial materials for
use in the place of previously-recycled materials where the recycled material has a processing role (such as
with spent bleed electrolyte which might need to be replaced with purchased sulfuric acid in a leach circuit).
        The commenter indicated that a processing unit choosing to continue recycling after failing a
legitimacy or Bevill test could face large costs.  The commenter indicated that for mineral processing
operations producing large quantities of secondary materials, the  cost of treating these materials as a Subtitle
C waste would most likely be economically prohibitive. The commenter believed that failing a legitimacy or
Bevill test would cause a facility to cease recycling of newly-identified secondary materials. (COMM58B)
        Response: The commenter has effectively described  the "worst case scenario" that could result from
the use of a quantified legitimacy test.  EPA believes that  the effects on a facility engaged in legitimate
recycling would not be this extreme.  As noted above, however, the Agency has withdrawn the requirement
for a quantitative legitimacy test from the final rule.|The final rule also does not include the tests relating to
use of hazaredous secondary materials in Bevill process units.
        Comment: The commenter  indicated that the RIA did not comply with OMB guidelines dictating
that the consequences of alternative actions be addressed, because the RIA failed to address the consequences
of a mineral processing facility passing or failing a legitimacy or Bevill recycling test. The commenter
suggested that the following be taken into account in order to provide for an accurate analysis of the proposed
        •        Consider the probability that processing units would: (a) pass the legitimacy and Bevill tests
                and continue recycling; or (b) fail these tests and cease recycling; and
        •        Consider the cost effects associated with any  reduction in industry recycling and consequent
                increase in the proportion of total newly-identified materials  that are treated and disposed.

        Response: The Agency has withdrawn the requirements for a quantitative legitimacy test and a
Bevill significantly affected test from the final rule.

        Comment: Another commenter mentioned that the proposed rule may cause decreased recycling of
and further negative economic impacts upon extra-industrial secondary materials, which constitute valuable
metal and mineral-bearing resources for the primary metals and mineral processing industry. The commenter
contended that if these extra-industrial materials were deemed solid wastes, and likely hazardous wastes,
many operations would likely discontinue the reuse or recovery of those materials in order to avoid being
subject to RCRA Subtitle C controls and permitting requirements.  As a result, the operating costs to the
generating industry would increase due  to the need to dispose of these materials. As with secondary
materials, the environmental costs due to land disposal would also  increase. The commenter argued that the
RIA did not account for these costs in the assessment of the proposed rule's economic impact.  (COMM36)
        Response:  Extra-industrial secondary materials are not newly identified mineral processing wastes
and are, accordingly, outside the scope of today's rulemaking.  Nonetheless, the Agency notes that the
provisions that would cause a decrease in recycling these materials (such as a quantitative  legitimacy test and
a Bevill significantly affected test) have been withdrawn from the final  rule.
        Comment:  Two commenters asserted that EPA was wrong to assume in the  RIA that all mineral
processing secondary materials that are currently being recycled  without being placed on the land will
continue to be exempt from RCRA regulation.  The commenters argued that this may  not be the case if EPA
decides to promulgate a "toxics-ratio" test or a "significantly affected" test. (COMM67, COMM85) One
commenter mentioned that  mineral recovery would be reduced as a result, affecting the economic benefit of
the proposed rule. (COMM85)
        Response: As noted above, the Agency has withdrawn the requirements for a quantitative legitimacy
test and a Bevill significantly affected test from the final rule.  As such, the Agency maintains that secondary
materials that are currently  being recycled without being placed on the land will not be affected by the final

        2.3    The Remining Assumption
        Comment:  One commenter argued that EPA's predictions regarding the "remining" of previously
discarded wastes were overly optimistic, and that there were only minimal benefits relating to remining as a
result of the rulemaking.  The commenter felt that the proposed rule was not adequate to encourage remining.
The commenter asserted that primary mineral processing operations will not remine historically discarded
wastes due to the complexities, risks, and expenses associated with EPA's proposed revisions to the
regulatory definition of solid waste.  The commenter believed that in order to make remining feasible, EPA
must revise the Bevill mixture rule and withdraw the application of the  TCLP to mineral processing wastes.

        Response: The Agency appreciates these comments and no longer considers increased remining a
"benefit" of this rule.
        Comment:  Another commenter indicated that EPA's analysis of the benefits associated with
remining fails to take into account two key facts. First, under current RCRA regulations, mining companies
can already remine previously disposed  hazardous mineral  processing wastes to recover their metallic values.
If the mineral processing wastes are excavated and destined for reclamation, their management prior to
reclamation, as well as the reclamation process itself, is not subject to RCRA Subtitle  C regulation. The
commenter cited 40 CFR 261.2(c)(3).
        Second, the major impediments to remining are not imposed by RCRA, but by CERCLA and CWA.
Under CERCLA, if a mining operation were to remine previously discarded wastes at  a given site, the mining
company would be potentially liable for the remediation of all environmental releases and damage ever

coming from the site. In addition, under CWA, the mining company runs the risk of being deemed
responsible for all discharges, including pre-existing discharges, from the site.  CWA would therefore require
the mining operation to treat all of the discharges so that they meet effluent limitations guidelines and water
quality standards.
        The commenter stressed that many mining companies have been attempting to persuade Congress to
adopt amendments to both CERCLA and CWA that would allow mining companies to engage in remining.
However, the mining industry has sought no such amendment to RCRA, because it presents no impediment.
As a result, the proposed rule, even if implemented, will not serve to encourage remining. (COMM57)
        Response:  EPA agrees that CERCLA and CWA regulations and their statutory basis present more
significant barriers to remining than does the RCRA program.
        Comment:  Another commenter argued that considering the cost savings associated with remining in
the compliance cost estimation process was inappropriate. The commenter suggested that EPA should
instead consider an industry's opportunity cost in investing in processes with lower returns  on investments
compared to those processes in other countries with greater returns on investments. The commenter
contended that EPA  is arguing both sides of the argument in that there should be ore cutoff grades, normal
operating ranges, and efficiency standards, while at the same time encouraging the reprocessing of wastes to
save money. The commenter argued that EPA was trying to regulate outside of its jurisdiction because the
economics of industry's processes are the responsibility of industry, not EPA. (COMM40)
        Response:  The Agency appreciates these comments and no longer considers increased remining a
"benefit" of this rule.
        Comment:  A fourth commenter indicated that it does not have knowledge of direct cost savings
related to remining but, based on the commenter1 s knowledge of the costs incurred in the traditional cleanup
and reclamation of old mine sites, believed that the cost savings associated with remining could be substantial
and may  represent hundreds of millions of dollars. The commenter also made the following point:
               "The proposal to treat such materials as being recycled within the mineral
        processing and mineral beneficiation industry sectors provides a means for recovery of
        mineral values from materials which might otherwise have been disposed of, and also
        provides for environmental protection through the standards regarding the land-based
        storage and  process units where these materials are stored prior to recycling."  (COMM74)
        Response:  Because characteristic sludges and by-products from mineral processing facilities are not
considered to be solid wastes when reclaimed under current regulations, EPA does not believe that these
materials would benefit from the conditional exclusion for mineral processing secondary materials in  the final
rule. With respect to spent materials, potential cost savings may occur from the final rule due to longer
accumulation times in non-land based storage units such as tanks, containers and buildings. Previously,
storage in these units without a permit would be limited to 90 days. 40 CFR §262.34. However, under the
final rule, these materials may be stored for up to  1 year provided that at least 75 percent of the material is
recycled in that time. EPA has not quantified the  extent of these cost savings.
        Comment:  A fifth commenter suggested that EPA examine the actual intended benefits and cost
effectiveness of remining (e.g., how many acres of land would be remined and remediated; or how many tons
of sludges and by-products would be recycled; or  how many tons of mineral materials would be recovered.)
This commenter requested that EPA provide information on how the anticipated results of the proposed rule
fits into EPA's long  term strategy of regulating mining wastes.  (LCOMM3)
       Response:  Despite numerous data collection attempts, the Agency does not have sufficient
information on abandoned waste piles to conduct  the type of analysis requested by the commenter.

        Comment:  One commenter argued that the benefits associated with the remining of "historically
discarded materials" were overstated. The commenter stated that the rule presents a large risk to mineral
processing facilities in that they may be reluctant to remine recyclable materials if the materials that they
process in existing process units are determined to be outside the scope of the RCRA exemption.

        Response: The Agency appreciates these comments and no longer considers increased remining a
"benefit" of this rule.

3.      Cost Analysis

        3.1    General
        Comment:  A commenter asserted that the costs associated with land disposal should be compared
to the status quo for compliance cost estimates instead of being compared with recycling costs. (COMM40)

        Response: The commenter may have misinterpreted the purpose of the comparison between land
disposal costs and recycling costs, which was to determine whether the rule would encourage recycling. EPA
is aware that not all material can be recycled. However, EPA believes that land disposal restrictions usually
result in an increase in the amount of material being recycled, due to operators reevaluating the economics of
recycling (i.e., comparing the costs of recycling with the "new cost" of treatment and disposal). The function
of predicting increases (or decreases) in recycling is separate from the overall cost benefits evaluation of the
        Comment:  This commenter also argued that mercury-bearing mineral processing residues would
most likely have to be treated via roasting and retort (rather than cement stabilization, as modeled in the RIA)
because disposal of mercury-bearing mineral processing residues is not available in the United States.  The
commenter contended that retorting alone would drive the estimated compliance costs up considerably.

        Response: The Agency does not believe that costs  are understated.  While high mercury streams
need to be treated using roasting and retort prior to land disposal of the residues, the Agency believes that low
mercury streams can be treated using cement stabilization.  The Agency's data do not indicate any mineral
processing streams have a high mercury content, and the commenter has not supplied any  new data indicating
the existence of newly identified high mercury streams.

        3.2    Multipliers
        Comment:  One commenter indicated that EPA had not provided any reasoning or source for the
specific multipliers used to represent the percentage of the waste stream that has been recycled and the
percentage that is considered to  be hazardous.  (COMM58B)
        Response: EPA agrees that the derivation of the multipliers was not well documented. The final rule
replaces these multipliers. The new multipliers are based on data reflecting management of F006 and K061
(two listed wastes for which recycling increased after  LDRs  went into place), the Agency's knowledge of
current  industry practice, and best engineering judgment.  More information on the derivation of these
multipliers can be found in Appendix A of the RIA.

        Comment:  This commenter stated that EPA had used the same multipliers for categories where
waste streams are known to be partially recycled with certainty ("YS") and those assumed to be partially
recycled ("YS?"). Furthermore, the commenter felt that the multipliers used under the uncertainty columns,
"Y?" and "YS?" should be generally higher than the corresponding ones used under the certainty columns
"Y" and "YS". However, only one out of the six boxes reflects this pattern. (COMM58B)

        Response:  EPA agrees that the multipliers for the YS and YS? categories should be different, and
has incorporated this change in the new multipliers developed to model the shifts which may occur as a result
of this rule.  These new multipliers also reflect the pattern that the multipliers used for Y? and YS? are higher
than those for Y and YS (i.e., more waste is sent to treatment and disposal for streams that are only suspected
to be fully or partially recycled).

        3.3    Rounding
        Comment:  One commenter stated that EPA used an inconsistent rounding method. For example.
67,500 is rounded off to 68,000 and  112,500 is rounded off to 110,000 and 174,000 is rounded off to
170,000. (COMM58B)
        Response:  Throughout the RIA, including the three examples cited by the commenter, figures were
rounded to two significant digits. Use of significant digits, common in most scientific calculations, allows for
a general estimate to be presented without the false precision that would be implied by reporting all digits
carried through a complex set of calculations.

        3.4    Waste Generation  Rates and Facility Averages
        Comment:  This commenter also stated that EPA inconsistently estimated waste generation rates
when data were not available.  The commenter indicated that for a substantial proportion of the waste
streams, EPA apparently used a single figure and applied it across the board for minimum, maximum, and
expected scenarios.  In addition, the source of these figures is not stated. (COMM58B)
        Response:  The Agency disagrees with the commenter's contention that the waste generation rates
were inconsistently estimated.  As stated in the RIA, single "reported" waste generation rates were used for
all three costing scenarios when they  were available. The source of the reported waste generation rates can be
found in the Identification Background Document's description of each waste stream.  Separate waste
generation rates for the three costing  scenarios were estimated only when a reported value was not available,
using the procedures outlined in Section 3.3 of the December RIA.
        Comment:  One commenter objected to the way facility averages were calculated. The commenter
indicated that the maximum number of facilities generating waste with 1-10 percent solids content in the
copper sector is 10 facilities. However, EPA has  used  14 facilities to calculate the overall average figures.
The use of 14 facilities as opposed to 10 for calculating the averages will underestimate the cost impact.
        Response: The Agency notes that this point no longer applies to the copper sector due to revisions to
the input data performed in response  to public comment. Nonetheless, EPA would like to address the
commenters concern. The cost model assumes that each facility generating waste above the on-site threshold
will build a single treatment system on-site to treat and dispose all of the waste. Therefore, all wastes at a site
are assumed to be aggregated to the extent possible before treatment and disposal (i.e., all waste streams
requiring dewatering are commingled prior to dewatering, and all streams  requiring stabilization are mixed
together, including the dewatered mass from neutralization and dewatering). In the table below, for example,
6 facilities would need to build treatment systems. The average facility generation rates used in the modeling
are 10,000 mt/yr of solids, and 22,167mt/yr of wastewaters.  These generation rates were calculated by
summing the total facility generation  rates within physical form categories and dividing by the maximum
number of facilities in the sector that need to build treatment systems. Similarly, in the December RIA, in the
copper sector, a single solid waste stream was generated by 14 facilities, while many of the other waste
streams were generated by 10 facilities. Thus in the December RIA, 14 facilities in the copper sector required
on site treatment, and the average facility  generation rates were calculated based on  14 facilities building
treatment systems.

        While this method of calculating quantities to be treated by the model "average facility" in a sector
sometimes underestimates the cost to some of the facilities, EPA has found this method of calculating total
sector cost to the most accurate method available, given the limitations of the input data. EPA also reminds
the commenter that the purpose of this analysis was to estimate the total cost of this rulemaking, not to
determine the cost of compliance at a particular facility.
Number of

Average Facility

Total Facility
: 22,166
        Comment:  One commenter indicated that for some waste streams the amount to be recycled has
been underestimated. The commenter cited tankhouse slimes, and WWTP sludge in the copper sector as
examples. This commenter added that the amount to be recycled is the difference between the waste
generated and the amount to be treated and disposed. (COMM58B)

        Response:  The commenter may have misunderstood the manipulation of the input data used to
account for uncertainty with regard to both hazard characteristics and recycling. The Agency categorized
each waste stream into a portion considered to be non-hazardous, and a hazardous portion, some of which is
treated and disposed, and some of which is recycled.  The amount of waste to be recycled is the difference
between the portion of the waste stream considered to be hazardous and the amount to be treated and
disposed. For example, using the data for the copper sector from the December RIA, both tankhouse slimes
and WWTP sludge have a hazard characteristic of Y? (only suspected to be hazardous). Therefore, in the
minimum value case these streams are not considered to be hazardous,  and drop out of the analysis, while in
the expected value case, only half of each stream is counted, and in the  maximum value case each entire
stream is considered to be hazardous.  It is these hazardous portions (in the expected and maximum value
cases) that are divided between treatment/disposal and recycling.

        Comment:  One commenter stated that EPA has made some calculation errors in combining the
matrices and waste generation rates to arrive at the quantities to be treated/disposed/recycled.  For example,
calculations of quantities for copper scrubber blowdown and surface impoundment waste liquids for copper
appear to be incorrect. (COMM58B)

        Response:  EPA has carefully reviewed the calculations for these two wastes streams and cannot
find any errors.  Because the commenter has not suggested any revised  quantities, the Agency cannot respond
to this criticism in more detail.

        3.5    Cost Functions
        Comment:  One commenter stated that it was their understanding that a very limited amount of
actual cost data was used to derive the cost functions employed in the RIA.  The use of such a limited number
of actual "data points" to generate the cost functions may render the quality of generalizations based on these
cost functions to be unreliable. Further, a visual examination of most of the cost functions reveals that the
EPA is assuming decreasing costs for almost the entire range of output. This implies that for all the waste

streams that the EPA has considered, the per unit cost of disposal never increases, irrespective of the amount
of waste being treated and disposed.  (COMM58B)
        Response:  EPA acknowledges that it used a limited number of data points to develop the cost
functions employed in the cost model, but disagrees with the commenter's contention that the cost model
results are unreliable. EPA used these cost functions to estimate the national impact of the rule and to
estimate the costs at model facilities, not to estimate the specific costs at actual facilities.  The Agency
believes that the cost functions are of sufficient quality to accomplish this purpose. In addition, EPA believes
that cost functions that reflect positive economies of scale (the commenters "decreasing costs") accurately
represent the costs of treatment technologies and equipment for which capacity (volume) increases more
rapidly than area (basis of cost).
        Comment: One commenter pointed out that EPA did not include O & M costs associated with
storage and recycling. The commenter felt that as a result, the storage costs have been underestimated which,
in turn,  led EPA to underestimate the incremental LDR costs for the Prior Treatment and No Prior Treatment
baselines under Option  1 and the No Prior Treatment baseline under Option 2. (COMM58B)
        Response:  The Agency agrees  with the commenter that total storage costs were understated and
notes that the O & M costs associated with storage have been included in the revised RIA. Nonetheless,
because the analysis was static (i.e., the amount of material stored did not increase or decrease as a result of
the rule), the major storage O & M costs were associated with moving the material into and out of the storage
units, which should be primarily a function of the amount of material being stored rather than the type of
storage unit. Therefore, although the total storage costs were understated, the effect on the incremental sector
cost and total industry incremental costs should have been minor.
        Comment: One commenter noted an inconsistency with the annualization formula that  EPA used to
determine the before-tax annualized cost (page F-25, December RIA). The commenter said there appear to
be typographical errors  in the second and third components of this formula:.
        (Capital  Costs)*(CRF) + (Annual Capital + O&M  Costs) + (Closure Costs)/(1.072I)*(CRF)
        The commenter believed the actual formula used by EPA to determine the before-tax annualized cost
was as follows:
        (Capital  Costs)*CRF + (O&M costs) + (Closure Costs)*CRF/1.0721
        Response:  While EPA concedes that the expression:
        (Capital  Costs)*CRF + (Annual Capital + O&M costs) + (Closure Costs)*CRF/1.0721
which is very similar to the commenter's suggested expression, would be clearer than the expression which
appeared in the RIA, both expressions are mathematically equivalent. The Agency also notes that while
annual capital costs do not appear in many of the calculations, they are included in the formula for
completeness.  Annual capital cost are treated as if they were O&M costs (because they reoccur every year),
rather than being considered with  the year one capital costs.

        3.6    Calculations
        Comment:  Under Option 1 Prior Treatment Baseline, the method used to calculate the incremental
LDR costs is inconsistent with the methodology used in other scenarios. The incremental  LDR costs under
Option 1 with No Prior  Treatment are calculated by multiplying the number of facilities for each waste stream
by the total storage cost and adding up the figures for the waste streams. With respect to copper, these waste
streams are acid plant blowdown,  APC dust/sludge, tankhouse slimes, and WWTP sludge. EPA has not used
its methodology consistently in arriving at these results. Typically, EPA has multiplied the average cost

figures with the maximum number of facilities to arrive at the total cost figures. In this case, however, the
EPA has used the number of facilities for each waste stream in deriving the total cost results. (COMM58B)

        Response:  EPA believes the commenter is actually referring to Option 1 with Prior Treatment in the
second sentence.  Assuming this is the case, EPA agrees with the commenter that storage costs were
inconsistently scaled up between baselines, and notes that this inconsistency has been corrected. In the final
RIA, the average facility storage cost is calculated for each stream. This average cost is multiplied by the
number of facilities recycling that waste stream, and these sector stream totals are added together to get the
total sector storage cost. In all options and baselines, these total sector costs are used to calculate the total
sector incremental storage cost, which is added to the total sector incremental treatment and disposal cost and
the total sector record keeping cost to determine the total sector cost.  Finally, this total sector cost is divided
by the maximum number of facilities generating hazardous waste to determine the  incremental average
facility sector cost.

        3.7    Assumptions
        Comment:  One commenter provided a detailed review of the steps EPA took in conducting the cost
analysis, and attempted to recreate EPA's calculations.  In restating the assumptions the Agency made, the
commenter incorrectly noted the following: (COMM58B)

        •      The "Prior Treatment" scenario assumes that spent materials that  are recycled are stored in
               compliance with full RCRA Subtitle C controls.  This scenario further assumes that prior to
               disposal, byproducts and sludges are decharacterized.  For spent materials, it assumes that
               full Universal Treatment Standards (UTS) are  carried out prior to disposal.

        •      Under Option 2, EPA believes that those materials, which EPA currently views as "spent"
               materials and requiring storage under RCRA Subtitle C conditions prior to recycling, would
               continue to require such handling under this option.  Recycling through a Bevill-exempt unit
               of materials considered by EPA to be newly identified materials would not be permitted.
               (Industry currently recycles certain materials through Bevill-exempt units to recover the
               metal values contained in these materials.  The industry believes that such recycling is
               permissible under current law.)
        •      The following conversion rates were used:
               1 mt = 66.07 gallons;

               1 mt = 8.8 cubic feet; and
               1 mt = 0.33 cubic yard.
        Response:  EPA would like to clarify that in the Prior  Treatment scenario, prior to disposal all types
of materials are decharacterized, not treated to UTS levels.  Option 2  allowed materials to be recycled to
Bevill units|!(as does the final rule).  (The Agency notes that Option 2 is not considered in final RIA.)  Finally,
EPA used the conversion rate of 1 mt = 2204.6 Ibs, with an assumed density of liquids of 62.4 lb/ft3 to arrive
at the following conversions:   1 mt = 264.28 gallons = 35.33 ft3 = 1.3 yd3.

        Comment:  One commenter noted that the cost figures in the RIA text are different from those in the
RIA tables.

        Response:  The costs in the tables were the correct estimates.

4.      Specific Mineral Processing Sectors and Facilities
        Comment: One commenter questioned EPA's estimate of the number of facilities that would be
affected by the proposed rule. The commenter stated that the Profile of the Metals Mining Industry indicates
that there are 873 metal mining facilities, and EPA has studied approximately 200 mineral processing
facilities and found over 350 secondary materials. Given the above numbers, the commenter wanted to know-
how EPA arrived at the estimate that only 181 facilities would be affected by this rulemaking.  In addition,
the commenter questioned EPA's assumption of one land-based unit per facility (61  FR 2367), and whether
there is data supporting that assumption.  (COMM40)
        Response:  This rulemaking applies to facilities generating hazardous mineral processing wastes
from primary mineral processing operations. Therefore, no mines will be affected except those co-located
with mineral processing operations. Mines that only conduct extraction and beneficiation operations are
outside the scope of the rulemaking.  Further, because some of the facilities conducting mineral processing
operations do not generate hazardous waste, not all of the 200 mineral processing facilities will be affected.
The number of land-based units per facility was  estimated from field experience, but does not influence the
number of facilities affected. Since the proposed rule, EPA has received new information for some sectors
indicating that several additional facilities have closed down, thereby further reducing the estimate of affected
facilities in today's rulemaking.
        Comment:  Two commenters argued that the RIA underestimated the potential financial impacts of
the proposed rule due to significant errors in EPA's assumptions and baseline data.  (COMM61, COMM64)
One commenter provided more detail, arguing that EPA underestimated the capital and operating costs of
beryllium waste treatment at the Brush Wellman facility in Delta, Utah.  This commenter mentioned that it
had difficulty determining how EPA arrived at cost estimates, but felt that a summary of the costs would
Capital $
$ 836,425
$ 1,258,737
        This commenter had a consultant perform a preliminary cost estimate for treatment of just one of
their beryllium waste streams, raffmate.  The overall capital and operating costs were significantly higher:
(1) capital cost: $ 5,013,255; and (2) O&M cost:  $1,863,499. The commenter added that it was unclear
whether the cost of the construction of the stabilized sludge disposal cell used in beryllium waste treatment
was included in EPA's cost estimates. (COMM61) Both commenters argued that EPA clearly
underestimated the potential financial impact of the proposed rulemaking upon the commenter's operation.
        Response:  EPA notes that several of the waste streams in question are beneficiation wastes, and
will not be affected by this rulemaking; they were included in the December 1995 RIA due to an oversight.
Nonetheless, the Agency acknowledges receipt of this new information,  and believes that the discrepancy in
cost between the commenter's analysis and EPA's cost estimates occurs for three reasons. First, a review of
the commenter's treatment process revealed that the commenters process appears to include an extra
treatment step, as well as the construction of a sludge disposal cell. Second, although the Brush Wellman
facility is the only facility generating  several of the waste streams in the  beryllium sector, these generation
rates were apportioned to two facilities in developing the average facility estimates for the RIA. Therefore, it
could be expected that the average treatment costs for the model facility in the RIA would be less than the

actual costs at the Brush Wellman facility.  The total sector costs for the RIA, however, are more likely to
represent the impact of the rule on the entire sector.  Finally, EPA used average facilities to estimate the
national impact of the rule and to estimate the costs  at model facilities, not to estimate the specific costs at
actual facilities.
        Comment:  Two commenters indicated that the RIA waste estimates for the commenters' operations
vary from the 1995 actual tonnages recorded by the  commenters (COMM61, COMM64):
Barren Filtrate
Bertrandite Thickener Slurry
Beryl Thickener Slurry
EPA Estimate (tons)
1995 Actual
        Response:  EPA will incorporate this new information into the Identification Background Document.

        Comment:  One commenter indicated that it was very difficult to correlate how EPA's general
assumptions on treatment concepts apply to the commenter's Delta, Utah operations, but the waste tonnage
determined by EPA for the beryllium sector as a whole in the RIA are as follows:
        Neutralized Waste
        Dewatered Waste
        Stabilized Waste
        Waste Disposed
      223,500 TPY
       33,525 TPY
       16,529 TPY
27,920 TPY
        The commenter mentioned that for the raffinate generated at it's facility, assuming that it is classified
as a hazardous waste, it would have to first neutralize the raffinate, then dewater and stabilize the treatment
sludge.  The commenter had a consultant develop a preliminary estimate of the tonnages of waste that would
have to be treated at its facility (COMM61):
        Raffinate to be neutralized                             367,000 TPY
        Neutralized Sludge to be Dewatered (30% solids)  121,110 TPY
        Dewatered Sludge to be Stabilized (dry weight)            40,370 TPY
        Final Waste to be Disposed with 50% cement             60,555 TPY

        Two commenters stated that as a result of the above figures, it appears that the EPA estimates of the
potential scale of the waste treatment and handling impacts of the proposed rule are underestimated.
        Response: EPA recognizes that its estimates may be inaccurate when applied to any specific
facility.  As indicated above, the purpose of this analysis is to project total sector and total industry costs.
Due to a number of differences in assumptions,  such as amount recycled and number of facilities generating
wastes, EPA's estimates  have a different basis than those presented by the commenters.
        Comment: One commenter presented a case study of how the proposal could force a change in
management practices that have not been considered in the RIA. The commenter outlined its current
management practices with respect to smelter furnace brick and revert and asserted that under the proposed
rule these materials would be affected in two ways: (1) the brick and revert would be subject to a legitimacy
test which they could fail, and (2) assuming that the materials pass the legitimacy test, recovery of these
materials may cause tailing impoundments to lose coverage under the Bevill exclusion. The commenter
determined that there are four management options under the proposed rule, and that all lead to with negative
economic impacts upon the commentefs operations.

        The commenter mentioned that the RIA does not appear to address smelter furnace brick and revert.
 The commenter asserted that these materials are not wastes unless they are actually discarded, but they could
 become subject to RCRA Subtitle C regulation as a result of the proposed rule. The commenter argued that
 EPA's failure to consider smelter furnace brick and revert in the RIA, coupled with the fact that these
 materials could become subject to regulation, will cause the commenter to adopt the high cost treatment
 scenario of sending the material to a hazardous waste disposal facility.  (COMM67)
        Response: EPA notes first that the commenter has mischaracterized spent furnace brick as
 "becoming" subject to RCRA jurisdiction as a result of the proposed rule. Spent furnace brick is currently
 classified as a spent material which when reclaimed is already currently subject to jurisdiction.  40 CFR
 §261,2(c)(3). EPA also notes that the quantified legitimacy test referred to by the commenter has been
 removed from the final rule.  EPA also notes that the "significantly affects" test for materials being added to
 Bevill process units has also been removed from the final rule.  Finally, the commenter's statement that the
 proposed rule would result in the copper brick and revert material being sent to a hazardous waste disposal
 facility is unsupported. The commenter has failed to identify this regulatory response as a least cost
 alternative mostly likely to be undertaken in the event of promulgating the final rule as proposed.
        Comment: One commenter indicated that EPA failed to consider the cost of the Bevill mixture rule
 in the RIA. The commenter argued that if EPA continues to believe that the leach  step in the Chemical Plant
 is acid digestion and hence mineral processing, there would be significant economic consequences to
 Molycorp's Mountain Pass operations.  The commenter contended that these costs would be unwarranted
 given the ability  of the commenter's tailings pond to immobilize hazardous  constituents of concern from the
 wastes generated by the facility. (COMM68)
        Response: EPA disagrees with the commenter that costs resulting from the Agency's previous
 determination that the leach step in Molycorp's mountain pass facility constitutes mineral processing is
 attributable to the Phase IV LDR proposed and final rulemakings. These  costs are attributable to the
 Agency's 1989 final rulemaking demarcating beneficiation and mineral processing materials.
        Comment: One commenter stated that the RIA underestimated the economic impact of the proposed
 rule upon the rare earths sector of the mineral processing industry. The commenter argued that EPA's
 estimates were unreliable because they are based upon information taken from the  Identification Background
 Document, which has been shown to contain numerous errors, especially concerning the commenter's
 operations. The commenter pointed out that the estimates EPA presented in the RIA were based on several
 waste streams identified for the rare earths sector in general, and for Molycorp's Mountain Pass facility in
 particular, that are not generated.
        The commenter commissioned a study to  evaluate the potential cost impacts of the Bevill
 Amendment changes in EPA's proposed LDR rule to  its facility. Based on a scenario of on-site treatment
 and disposal of wastes that would be classified as  hazardous due to the proposed rule, the study estimated
 that the capital costs to the commenter's facility would be $12.2 million and annual operating costs would be
 $ 1.2 million.  Assuming that the commenter could not obtain a permit for on-site treatment, an additional cost
 of $ 1.2 million for off-site treatment would be required in addition to $3.6 million  in capital cost and
 approximately $1 million in annual operating costs. The commenter argued that these multimillion dollar
 costs would seriously cripple the production of bastnasite ore at its facility, the sole domestic producer and
 major supplier of cerium products. The commenter felt that the proposed  rule would ultimately result in lost
jobs and dollars to overseas producers without added environmental protection. (COMM68)
        Response:  EPA used all available data in preparing the Identification Background Document, and
 solicited additional data in the preamble to the proposed rule, in recognition of the  data limitations.  EPA has
 incorporated into the Identification Background Document the new information about the rare earth sector
 that was provided by the commenter.  EPA cannot remark on the commenter's economic analysis because it

was not included with those comments. EPA again points out that the analysis conducted in the RIA was a
screening level analysis to determine the total industry impact of the rule, not to determine the compliance
cost at a particular facility.
        Comment:  One commenter did not agree with the finding that the proposed rule would have no
impact upon the lightweight aggregate sector of the mineral processing industry. The commenter referenced
Section 6.1.3 of the RIA, where EPA identified three management choices available to facilities that generate
APC dust from lightweight aggregate production and burn listed hazardous wastes as fuel. The commenter
argued that treatment and disposal, as a routine practice, would become prohibitively expensive. The
commenter added that cost would vary from plant to plant but, using current disposal costs, it would increase
production costs to the extent that burning hazardous waste fuel would no longer be economically feasible. In
addition, the commenter also asserted that recycling the dust to the kiln without reclamation may not always
be technically feasible, but in any event it is typical for some portion of a plant's production be placed on the
land as structural fill. (COMM39)

        Response:  EPA has removed consideration of the Bevill status of lightweight aggregate kiln dust
from the LDR Phase IV final rule.

        Comment:  One commenter argued that the proposed rule presents a heavy burden to the regulated
industry, and EPA seemed to dismiss the fact that compliance costs could exceed 5 percent of a mineral
product's value.  The commenter added that 8 out of 17 mineral processing sectors risk individual facility
closings due to the proposed rule, under the no prior treatment baseline. (COMM40)
        Response:  EPA has completed a thorough economic impact analysis of the Phase IV LDR final
rule. The Agency has concluded the estimated $ 10 million compliance cost of the final rule will not pose
undue burden on the mining industry.  In addition, the Agency notes that the commenter was describing
results for the no prior treatment baseline, which assumes facilities were not in compliance with baseline

5.      Risk Assessment

        5.1    General
        Comment:  A commenter disagreed with EPA's comparison of the LDR Phase II cost-benefit and
risk analyses results  to those of the LDR Supplemental rule, because the Phase II rule dealt with organic
compounds that have different transport characteristics and potentially different health effects than metals in
mineral processing wastes.  (COMM58A)

        Response:  The risk and benefits analyses for the mineral processing LDRs stand on their  own and
do not depend on the results of the Phase II LDR analysis. Since the December RIA, EPA has performed
additional groundwater modeling that employed constituent-specific dilution attenuation factors (DAFs).
These DAFs were developed for all of the identified mineral processing waste constituents using constituent
concentrations and facility characteristics data from the mineral processing industry as inputs to the
EPACMTP model.  This approach takes into  account the concentration-specific fate and transport
characteristics of all  of the inorganic constituents for which risks were modeled, and is consistent with EPA
approaches in other recent rulemakings (for example, HWIR-Waste).

        5.2    Hazard Assessment
        Comment:  A commenter observed that an incorrect reference dose for manganese was used in the
risk assessment calculations.  (COMM58A)

        Response:  Since the December RIA, EPA has performed revised risk and benefit modeling,
employing the most current toxicity values obtained from the IRIS database. The change to the toxicity value
for manganese had very little impact on the results of the revised risk and benefits calculations, since
manganese was not a dominant contributor to estimated health risks (hazard indices) for any waste stream.
        Comment: Two commenters remarked that beryllium,  by EPA's own determination, has not been
treated as an ingestion carcinogen in several recent rulemakings, and therefore, EPA's LDR Supplemental
rule RIA risk assessment for beryllium should be based only on  non-carcinogenic endpoints.  (COMM58A,
        Response:  EPA agrees.  The risk calculations supporting the revised RIA no longer treat beryllium
as an ingestion pathway carcinogen.
        Comment: One commenter argued that the beryllium reference dose used in the risk assessment is
overly conservative, and called for a risk calculation with a revised reference dose for beryllium.  The
commenter felt the reference dose for beryllium was too conservative because (I) it was based on No
Observed Adverse Effect Levels (NOAELs), rather than Lowest Observed Effect Levels (LOAELs), and (2)
the uncertainty factors used to develop the reference dose were very high. The commenter also presented
alternative toxicity data and uncertainty factors which, it argued, would raise the RfD significantly.
        Response:  EPA believes that the Reference Dose for beryllium exposure is adequately documented
in IRIS, and that the reference dose was derived appropriately using data from the best available peer-
reviewed toxicological study. The commenter is correct that EPA is currently reviewing the approach used to
establish RfDs for beryllium and for several other substances, but that review is not yet complete. When this
review is complete, EPA may revise the risk and benefits estimates for beryllium-containing wastes if the
RfD value changes significantly.  It should be noted that there is no assurance that the review will result in an
increase in the RfD, as maintained by the commenter.
        Comment:  A commenter noted that the most recent arsenic cancer slope factor was  not used in the
LDR Supplemental rule RIA risk assessment.  (COMM58A)
        Response: EPA agrees.  In risk work to support subsequent revisions to the RIA, EPA has used the
revised value.
        Comment:  A commenter criticized the current arsenic cancer slope factor as being overly
conservative.  The commenter cited  several criticisms of the underlying toxicological study which, it
maintained, undermine the validity of the CSF derivation.  These criticisms have to do with how exposures
were calculated in the study, and the contribution of background arsenic exposures to the observed cancer
incidence.  The commenter further argues that arsenic exhibits a sub-linear, rather than  linear, dose-response
relationship at low doses.  The commenter provided alternative CSF values which were calculated using
different data sets and dose-response extrapolation models. (COMM58A)
        Response: The risk and benefits analysis for the mineral processing LDRs employed the most
current CSF value from IRIS (1.5 (mg/kg-day)"1).  The commenter provides a table of ingestion slope factor
values for arsenic derived using different dose-response models and water intake assumptions, ranging from
1.98 (mg/kg-day)"'  to 0.86 (mg/kg-day)"' , and suggests that a value as low as 0.77 (mg/kg-day)"' would be
credible. EPA does not feel that the alternative models and water intake assumptions suggested by the
commenter are significantly superior to those used to derive the value in IRIS. In addition, all of the
alternative estimates are very close to the slope factor from IRIS, the lowest being just one-half this value.
The clustering of the CSF values so closely together at values near to that used by EPA undermines the

commenter's argument that the uncertainty associated with this CSF value is unusually high. In addition,
using any of the commenter's slope factors would not have significant impact on the RIA, because only order-
of-magnitude distinctions in risk levels are made in the risk and benefits assessments.
        Comment: One commenter argued that the arsenic reference dose is too conservative and that it
should be raised. The commenter cited a study from the scientific literature that suggests EPA did not
adequately assess the contributions of inorganic arsenic in food, and that EPA used unreliable toxicological
study results in its calculation of the reference dose.  (COMM58A)
        Response:  As was the case for beryllium, EPA used the latest IRIS Reference Dose value for the
risk and benefits assessment. Because a large human epidemiologic study was used to derive the RfD instead
of animal studies, a relatively low uncertainty factor value (3) was used.  EPA considers the level of
uncertainty in the RfD to be only "moderate." EPA does not feel that the data are likely to support a
substantially higher RfD value. The commenter argues that the RfD should be approximately two-fold
higher. As was the case for the slope factor value, even if this argument is accepted, a change of this
magnitude would change the results of the risk and benefits assessment only marginally,  since hazard
quotients are calculated only in order-of-magnitude ranges. In addition, addition, even if the reference dose
were changed, the carcinogenic affects of arsenic would still dominate for all of the arsenic-containing wastes.

        Comment: A commenter observed that a reference dose for lead was derived based on the MCL for
lead, and pointed out that this action is contrary to EPA's published guidance on lead risk characterization.
This commenter  also maintained that the MCL for lead is "not a health-based standard." (COMM58A)
        Response:  EPA's MCL (Action Level) for lead in drinking water is, in  fact, intended to be health-
protective of small children against the adverse effects of lead exposure.  The MCL was set in part based on
the finding, using EPA's IEUBK model, that fewer than five percent of children drinking water at the MCL
level would have unsafe blood lead concentrations, as long as there  were  no other major sources of exposure.
The derivation is thus clearly health-based, even if economic considerations were also weighed during its
promulgation.  The commenter maintains that the only valid approach to evaluating potential lead impacts on
human health is to compare lead concentrations in drinking water to the MCL.  This is precisely what is done
through the use of the "derived RfD." A hazard quotient of greater than one for lead indicates nothing more
than that the calculated well concentration exceeds the MCL.  Whatever approach is used to indicate
exceedence this level, this does not affect the general findings of the risk  assessment that lead is a potential
health concern for the disposal of many waste streams pre-LDR and that the level of concern is reduced post-

       5.3     Exposure Assessment

                5.3.1          Proximity to Populations
       Comment: Two commenters disagreed with EPA's assumption that population densities and
prevalence of private ground water wells near mineral processing facilities are similar to those of Subtitle D
waste management facilities. (COMM57, COMM58A) One of the commenters stated that although
commercial waste management facilities tend to be located in population centers  and, thus, near to private
drinking water wells, integrated mineral processing facilities tend to be located in sparsely populated areas
that are far away from private residences and drinking water wells.  (COMM57)
       Response: In the absence of data on mineral processing facility, EPA has used the probability
distribution of well distances near Subtitle D facilities in the derivation of constituent-specific DAFs which
were used in the revised risk and benefits modeling for the mineral processing waste LDRs. While the
Agency believes  this approach has not resulted in substantial bias in the risk estimates, it is currently
gathering site-specific population density data for areas near mineral processing facilities.  While this analysis

is not yet complete, the preliminary findings of this assessment indicate substantial populations resident near
many of the facilities.  The degree of dependence on groundwater near the facilities is still being determined.
        Comment: One commenter pointed out that EPA failed to recognize that the metallic impurities
contained in mineral processing secondary materials occur naturally in soils throughout the area of the
processing facility. Therefore, the release of small quantities of such metals into the environment will not
significantly increase the total exposures or risks to nearby populations above those which already exist.

        Response: EPA does not have sufficient data on background exposures to naturally occurring
concentrations of waste constituents to address this issue quantitatively in the risk and benefits assessment.
Based on previous experience, however, the Agency does not believe that pre-existing exposures are as
significant as the commenter suggests. EPA also feels it has an obligation to protect the health of populations
near mineral processing facilities, irrespective of natural background  exposures. In fact, the commenter's
point would argue for more stringent,  not less stringent, controls on groundwater concentrations of
contaminants, if background exposures were already high.
        Comment: A commenter argued that EPA failed to account for the increased potential  for exposure
associated with the transportation of secondary materials to commercial hazardous waste disposal facilities
and disposal of the ultimate residues of treatment. The commenter asserts that the potential for traffic
accidents, spills, and drinking water well contamination is much higher if these materials are transported to
commercial hazardous waste disposal facilities than if the materials were treated on-site at an integrated
mining, beneficiation, and smelting  facility. The reason for this is that commercial hazardous waste disposal
facilities tend to be located in more  populous areas, while integrated mining, beneficiation, and smelting
facilities tend to be located in non-populous areas. (COMM57)
        Response: The data available to EPA indicate that the great majority of the mineral processing
wastes which are now managed on-site will continue to be managed on-site under the proposed regulatory
options because off-site transport would be uneconomic for all but a very few low-volume waste streams.
EPA also believes that the potential risks of waste releases from transportation accidents are much less that
the risks associated with on-site treatment and final disposal.

               5.3.2         Groundwater Transport Modeling
        Comment: A commenter objected to EPA's  use of a single, generic DAF value for the chemical
exposure calculations, and recommended that chemical-specific DAF values be used instead. Based on the
results of the commenter's sensitivity  analyses of various groundwater models, the commenter argued that
exposure-point chemical concentrations (and DAFs) are highly dependent on the chemical's
physical/chemical and environmental fate properties, the time period and source assumptions, and the
assumed distance to a drinking water well. The commenter also pointed to EPA's guidance for the
groundwater model used in the RIA risk assessment. The guidance showed chemical-specific DAF values
being used. (COMM58A)
        Response: EPA has conducted extensive additional risk modeling since the December RIA. This
modeling, consistent with the reviewer's comment, has incorporated constituent-specific DAF  values derived
specifically for mineral processing wastes and disposal facilities. All risk and benefits results in the revised
RIA are based on the constituent-specific DAFs which have been derived using data on waste composition,
constituent concentrations, and management unit sizes from mineral processing facilities.
        Comment:  A commenter requested that EPA reevaluate the DAF values and risks using the updated
groundwater modeling approach (EPACMTP) that was applied in the proposed Hazardous Waste

Identification Rule (HWIR-Waste) rulemaking.  The commenter noted that the EPACMTP does not use the
infinite source and infinite time assumptions and that the Monte Carlo analysis reportedly has been improved.
The commenter believes that the incorporation of these revisions will affect the range of DAFs used in the
EPA's LDR Supplemental Rule risk assessment and, thus, the calculated risks.  (COMM58A)
        Response: Consistent with this comment, EPA has used the EPACMTP model to derive
constituent-specific DAFs for all of the waste constituents.  These constituent-specific DAF values were used
to derive all of the risk and benefits estimates presented in the revised RIA.
        Comment: One commenter observed that many of the groundwater transport calculations are
incorrect because the total metal concentration was used rather than a measure of the leachable metal
concentration. The commenter remarked that EPA's use of the total metal concentration in the calculations
had a large impact on the risk characterization results. (COMM58A)

        Response: As noted above, the data used to estimate DAF values and risks has been changed in
revised risk modeling work done by EPA since the December RIA.  In the revised risk assessment for
wastewasters, the bulk concentration data were used as estimates of release concentrations.  For liquid
nonwastewaters (waste streams containing one to ten percent solids), EP extraction data for the solids were
used as release concentration estimates if they were available. Otherwise, bulk concentration data were used
as release concentrations. In the case of nonwastewaters (solid materials), the EP extraction data were used to
evaluate release concentrations when they were available. When EP  extraction data were not available (this
was only the case for about five of the waste streams), a conservative estimation procedure was employed,
which assumed that the release concentration for any constituent would be equal to the bulk concentration of
that constituent divided by 20.  EPA believes that this approach makes the best use of the available data,
provides prudently but not unreasonably conservative estimates of release concentrations, and minimizes the
potential biases associated with the lack of leachate data for some wastes.
       Comment: A commenter recommended that the infinite source and time-frame assumptions used in
the groundwater modeling (for the development of the DAFs) be replaced with a reduced time-period (e.g.,
1,000 years).  (COMM58A)
       Response:  In the derivation of the constituent-specific DAFs that are used to estimate risks and
benefits in the revised RIA, EPA employed the finite-source modeling methodology, consistent with this
reviewer's suggestion. EPA has, however, retained the 10,000-year modeling period, in order to be consistent
with previous regulatory risk analyses.

       Comment: A commenter disagreed with EPA's use of a Subtitle D facilities study to derive DAF
values. The commenter asserted that the DAF values should instead be based on a statistical analysis of
actual data for mineral processing facilities, and recommended that a survey of distances of mineral
processing facilities to drinking water wells, or a surrogate analysis, be performed.  (COMM58A)
       Response:  The derivation of constituent-specific DAFs for the revised RIA employed data that
came primarily from mineral processing facilities.  The distributions  of constituent concentrations and
constituent masses used in the finite source modeling came from a data base of mineral processing  waste
analyses. All of the available concentration data were used in the DAF derivation.  Hydrogeological and
meteorological settings used in the groundwater transport modeling were derived based on the geographical
distribution of mineral processing facilities identified in the data base. The same waste disposal unit types,
sizes, and configurations employed in the cost and economic analysis were used in the constituent-specific
DAF modeling.  The spatial distribution of receptor wells around Subtitle D facilities was retained, however,
since detailed information about receptor distributions around the mineral processing facilities was not

        Comment: A commenter observed that EPA has not conducted validation or site-specific modeling
efforts for the Supplemental Phase IV LDR rule to verify that the calculated concentrations at an assumed
drinking water well are reasonable.  (COMM58A)
        Response: The groundwater modeling performed for the risk and benefits analysis is intended to
provide a prudently conservative screening-level assessment of potential risks associated with long-term
transport of persistent inorganic pollutants from the population of waste disposal facilities taken as a whole.
It is not meant to provide estimates of current risks from any individual facility. At any site, groundwater
concentrations will vary depending on facility and waste characteristics, on hydrogeologic and meteorologic
conditions, and on well locations and monitoring strategy. Agreement with modeling results (e.g., a DAF
value) would be fortuitous.
        The agency is currently assembling data on specific mineral processing facilities which will help to
support or validate the risk screening level assessment.

        5.4    Scope of the Risk Assessment
        Comment: A commenter stated that the EPA's LDR Supplemental rule risk assessment is only a
screening-level analysis.  The commenter cited Administrator Browner's March 1995 EPA guidance on risk
characterization, which says that a "screening-level risk assessment" is only the first step in the risk
assessment process, and suggested that a more detailed and thorough risk assessment is required before any
final rulemaking. (COMM58A)
        Response:  The level of detail of any risk assessment should be determined by  the policy issue which
it addresses.  In the case of the mineral processing LDR, the generic risk assessment approach which was
taken was sufficient to identify which wastes presented the greatest hazard when disposed in unlined
facilities, to rank the potential risks by waste stream and commodity sector, to confirm that uncontrolled
disposal resulted in potential risks above levels of regulatory concern, and that treatment and disposal of
these wastes under  LDR standards resulted in effective risk reduction.  The numerical results for any waste
are, of course, quite uncertain, but the results taken in aggregate are sufficient to inform the regulatory
decision being made.
        In addition, EPA has selected a small sample of mineral processing facilities indicated as having
potentially high risks in the screening level assessment and assembled site-specific information which is used
to support more facility-specific discussion of risks in the revised RIA.
        Comment: One commenter argued that EPA failed to address population risks in the LDR
Supplemental Rule risk assessment, and that EPA must do so in order to conduct a meaningful cost-benefit
analysis. (COMM58A)
        Response:  As noted in response to the previous comments, EPA has gathered data concerning
populations residing near mineral processing facilities, and site-specific data related to potential exposure
pathways. These data re discussed in the revised RIA.

        5.5    Data Quality/Availability
        Comment: A commenter remarked that the chemical concentration database used for the risk
assessment was too limited to support the risk characterization.  The commenter argued that more data should
be gathered on chemical constituent concentrations for a range of mineral processing facilities and process
streams in order to  achieve a more detailed and  accurate risk assessment. (COMM58A)
        Response:  The data sources used to evaluate constituent concentrations for the mineral processing
wastes, and the limitations of these data sources, are discussed in detail in the RIA. As noted there, although
concentration data were available only for a minority of the wastes streams addressed in the economic
analysis, data were  available for most of the large-volume wastes, representing a high proportion of the total

mineral processing wastes. While the Agency would like to have had more information on constituent
concentrations, EPA believes that the data are sufficient to support the screening level analysis that was
performed, recognizing that the risk and benefits results for those wastes with little data are quite uncertain.
As noted in the RIA,  the lack of data for some waste streams results in a bias toward the underestimation of
LDR risks and benefits.
        Comment: One commenter noted that the teachable metal concentrations data used for the risk
assessment are too limited and argued that more of this data must be collected for the risk assessment to be
accurate. (COMM58A)
        Response: As noted above, EPA used all of the available leachate and bulk metals data in deriving
constituent-specific DAFs and in  evaluating risks and benefits. Leachate data were used preferentially to
estimate release concentrations, and these data were available for a large majority of the wastes streams
evaluated.  EPA agrees that the risk results derived for any individual waste sample are  quite uncertain.
However, the aggregate risk and benefit results are of sufficient quality to support the rulemaking.

        5.6    Risk Management
        Comment: One commenter argued that the "acceptable" lifetime cancer risk threshold for arsenic
used in the LDR Supplemental Rule RIA (10"5) should be increased from 10~4 to 10~3 to  make it consistent
with EPA's drinking water criteria, which carry a risk of approximately 10~3, and consistent with the target
risk adopted at an Superfund site  (5x10"4). The commenter also maintained that the background cancer risk
from food is on the order of 10'4 or higher. (COMM58A)
        Response: As noted above, EPA feels that it has the responsibility to protect the public from
incremental risks, irrespective of the risks posed by background exposures or other risk factors.  The levels of
regulatory concern used to tabulate benefits in the RIA (cancer risk of 10~5, hazard quotient of 1.0) were
consistent with those used by EPA in other regulatory analyses and rulemaking proceedings (e.g., LDRs  for
solvent wastes, HWIR-Waste).  It should be noted that these levels are only measurement benchmarks, and
are not decision criteria.

        5.7    Documentation
        Comment: One commenter noted that the risk  assessment document is insufficiently "transparent"
because it failed to fully present the chemical-specific risk calculations and results. The same commenter was
also unable to determine which  DAF values were used in the RIA. The commenter also noted that EPA did
not present an explanation of why some of the groundwater transport calculations used the EP Toxicity
values and others used total metal concentrations.  (COMM58A)
        Response: Since the December RIA, EPA has conducted additional risk and benefits assessment
calculations incorporating additional information provided by commenters and employing constituent-
specific, rather than generic, DAFs. These risk calculations are fully documented in the revised RIA. All of
the input data files and risk calculation spreadsheet files have been made available in electronic form to
        In the revised risk modeling, both  EP extraction and total metals concentrations (the latter divided by
20) are used, where available, as estimates of release concentrations of metals from wastes. The EP
extraction data are used because these are the only extraction data that EPA has for mineral processing
wastes.  Total metals data divided by twenty are used to  provide a conservative screening level estimate of
release concentrations from wastes, essentially assuming 100 percent leaching efficiency.

6.     Other Comments (UIC Comments)
       Comment: One commenter argued that the RIA is flawed if it was intended to include uraniurr
mining within the proposed underground injection ban. The commenter contended that this was evidenc
the fact that EPA assumed that only 20 facilities (8 non-hazardous) would be affected, when according t<
commenter, there would be a total of 31 wells associated with 16 uranium in-situ leaching operations tha
would be affected.  (COMM66)

       Response: EPA agrees with the commenter.  The RIA for the final rule does not model any urar
facilities within the universe of affected facilities.


        PAGE                |
                             |       EPA530-R-99-020h
13. Recipient's Accession No.
                                PB99-155 897
 4. Title and Subtitle                                                                                  j 5. Report Date
 Response to Comments Document: Land Disposal Restrictions-Phase IV: Final Rule Promulgating Treatment     I    April 1998
 Standards for Metal Wastes and Mineral Processing Wastes; Mineral Processing Secondary Materials and Bevill   16.
 Exclusion Issues; Treatment Standards for Hazardous Soils, and Exclusion of Recycled Wood Preserving Wastes; I
 Volume 8: Comments Related to Regulatory Impact Analysis for Newly Identified Mineral Processing Waste       I
 Issues Raised in First Supplemental Proposed Rule. January 25. 1996	
 7. Authors)
                            8. Performing Organization RepL No.
 9. Performing Organization Name and Address

  U.S. EPA
  401 M STREET, SW
                            10. Project/Task/Work Unit No.
                            11. Contract İ or Grant (G) No.
 12. Sponsoring Organization Name and Address
                            13. Type of Report & Period Covered

                             Response to Public Comment
 15. Supplementary Note"
 16. Abstract (Limit: 200 words)

 Responds to public comments related to the adequacy of the regulatory impact analysis for newly identified mineral processing waste issues
 in the first supplemental proposed rule. Addresses comments about the proposed regulatory requirements and predicted responses. Answers
 comments received on the cost analysis, specific mining sectors and facilities, and risk assessment.
 17. Document Analysis a. Descriptors
   b. Identifiers/Open-Ended Terms
   c. COSATI Field Group
 18. Availability Statement
| 19. Security Class (This Report)  | 21. No. of Pages
I UNCLASSIFIED            |           ^,

120. Security Class (This Page)   | 22. Price
[UNCLASSIFIED            |
                                   OPTIONAL FORM 272 (4-77)
                                   (Formerly NTIS-35)