A REPORT ON
 MINING
 NARRAGANSETT
 COAL
by

NEW ENGLAND FEDERAL REGIONAL COUNCIL

ENERGY RESOURCE DEVELOPMENT TASK FORCE
COAL COMMITTEE
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                  JULY 1977

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A REPORT ON
MINIi JG NARRAGANSETT COAL
BY
i EW ENGLAI D FEDERAL REGJO AL COUNCIL
ENERGY RESOURCE DEVELOPMENT TASK FORCE
COAL COMMITTEE
JULY U. 1977
W. R. R RTON.I CHAIRMAN
OB BIsFIOP GAw BLODGETI
1 ETER CLARK eETER N. FAIRBANK
ULLAINE DAY I(ICK MEISTER
RIcHARD KEPPLER JOSEPH SI JNOTT
DAVID O’CONNOR DAt N W. LAWRENCE
JOSEPH PECQRARO JOSEPH VITIc4
MARTIN J. IHORPE

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PREFACE
This report is a product of the New England Federal Regional Council’s
Energy Resource Development Task Force. The Federal Regional Council
is an interagency, intergovernmental coordination group. It’s purpose
is to make a very complicated three tiered governmental system efficient
and responsive to the real needs of all citizens. The Federal Regional
Council of New England membership includes the eleven principle grant
making federal agencies:
Community Services Administration
Department of Commerce
Department of Health, Education & Welfare
Department of Housing and Urban Development
Department of Interior
Department of Labor
Department of Transportation
Environmental Protection Agency
Federal Energy Administration
Farmers Home Administration
Law Enforcement Assistance Administration
and the Army Corps of Engineers, New England River Basins Commission,
the New England Regional Commission and the U.S. Civil Service Commission.
The Federal Regional Council’s Energy Resource Development Task Force
is composed of representatives of several federal agencies, the New
England Governors, the New England Regional Commission and the New
England River Basins Commission. The Task Force Chairman is Robert W.
Mitchell, FEA Regional Administrator.
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Principle objectives are to:
1. Reduce the Region’s high dependence on petroleum and its atten-
dant high costs.
2. Reduce the Region’s adverse weighted average energy cost as
compared with the balance of United States; and thereby,
3. Improve both New England’s energy posture and industrial investment
climate, by providing an inter—agency process that will most
efficiently meet anticipated needs and reduce the lead time
required for energy development.
The ‘77 work of’ the Task Force has been carried out under the leadership
of seven Federal agencies in 12 of the following l 4 specific work areas
covering the various aspects impacting upon energy in New England.
Environmental Protection Agency
Refineries
Bulk Power Plants
Energy Recovery
Federal Energy Administration
Energy Statistics & Projections
Gas Facilities Monitoring
Emergency Storage Monitoring
Wood Utilization
DOD - U.S. Corps of Engineers
Hydro—Electric
DOT — U.S. Coast Guard
Energy Related Marine Terminal Facilities
Bureau of Mines
Coal
Department of Commerce
Coastal Zone Management
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Department of Housing & Urban Development
Solar
Unassigned
-Outer Continental Shelf
Utility Corridors
The Coal Committee was formed to answer the question:
How can coal contribute in solving New England’s energy problems?
Actually, the potential for future coal use in New England will be
determined primarily by the answer to another question:
Can coal be utilized economically in New England in compliance
with environmental standards?
The Coal Committee attacked the above question from what is basically
a management by objectives approach. The basic objective was that
the answer to the above question should be: Yes.
The Committee’s initial report, entitled “New England Potential for
Increased Use of Coal”, was published in September 1976 and contained
27 specific action recommendations. Two of the priority recommendations
were that:
“A test project should be conducted at an existing power site
to determine the economics and environmental effects of burning
available coal at a New England power plant without retrofitting
of Flue Gas Desulfurization equipment.” and
“The present Narragansett Basin (coal exploration) study should
be funded to its completion.”
Both recommendations are in the process of’ implementation. This report
was prepared in response to questions about the feasibility of “Mining
Narragansett Coal .“
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Members of the Committee all have other primary assignments to carry
out within their respective agencies. The Coal Committee is an on-
going activity and will continue to work to facilitate the implementation
of the recommendations contained in the initial report. Comments and
questions from readers of Federal Regional Council Energy Resource Develop-
ment Reports, and new related information, are always welcome and should
be addressed to the Energy Resource Development Task Force Chairman,
Robert W. Mitchell, Federal Energy Administration, 150 Causeway Street,
Boston, Massachusetts O211 .
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CONTENTS
PAGE
INTRODUCTION 1
THE NARRAGANSETT BASIN COAL PROBLEM 2
PROBABLE NARRAGANSETT BASIN COAL-MINING TECHNIQUES 4
CONVENTIONAL MINING OF PI1 CHING SEAMS 4
INDUCED CAVING 6
HYDRAULIC MINING 6
LONG WALL MINING AND “ROADHEADERS” 9
AUGERING AND BORING 10
IN SITU GASIFICATION 10
CONCLUSIONS 12
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INTRODUCTION
In selecting a system to mine Narragansett Basin coal there
are several paramount concerns that will determine the process. The
system selected must be that which combines the highest degree of safety
for mine personnel with the lowest consistent mining cost per ton of
product. It must also combine maximum recovery of coal per acre consistent
with a due regard for the ecology of the area and with minimum surface
disturbance.
Within these parameters there are physical factors which
influence possible mining methods. These factors include:
(1) Topography and other physiographic conditions
(2) Amount and type of overburden
(3) Total size of the coal reserve in the block to be mined
(4) Coal seam characteristics including thickness, variability
and irregularities, dip or pitch of the seam, partings, hardness and
strength of the coal, nature and strength of seam roof and bottom,
presence and quantity of methane, quantity of water likely to be
encountered, nature and direction of faults, jointing, cleavage, folds,
and other geologic structural features affecting the seam.
These, and many other data must be collected, collated, and
reviewed before any design of a mining system can begin.
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THE NARRAGANSETT BASIN COAL PROBLEM
The coals of the Narragansett Basin involve no intrinsic
mining problems that have not been faced and overcome somewhere else.
But they have problems present in unique combination.
The identified beds of anthracite appear to be highly folded
so that most of the coal lies now in steeply pitching seams. Seams
which are broken, at irregular intervals, by the intense faulting
that the Narragansett basin has been subjected to. Coal can be mined
irrespective of dip or pitch involved. However, when the working
angle exceeds about 20 degrees, modern continuous conventional coal
mining methods cannot be applied and coal must be extracted using methods
more similar to those applied in metal mines pursuing pitching
deposits.
Not only do the Narragansett Basin seams suffer from intrinsic
problems, they also face extrinsic difficulties in the form of deep
overburden, high watertable, low, swampy terrain in some areas and an
urbanizing or urbanized surface in others, special “coastal zone” and
environmental concerns, and an ambient local political atmosphere that
can at best be characterized as ambivalent toward coal mining.
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This paper addresses itself to summarizing the probable
mining techniques that would best permit coal development within
economic and technologic possibility while making a successful
compromise with the phy. Lcal and cultural environmental realitY.
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PROBABLE NARRAGANSETT BASIN COAL MINING TECHNIQUES
The combination of steeply dipping coal beds with the
sensitive nature of the Narragansett Basin surface (wetlands, coastal
zone, and urban) is considered to preclude surface raining methods
for any large scale mining venture. Stripping ratios and land damage
would be excessive even when environmental, land use, and zoning
regulations would not prohibit surface mining incursions.
Entry for underground development would be either by slope or
by shaft. The former technique likely when a pitching bed is being
developed near the surface, the latter method if the coal block being
developed lies beneath deep cover.
Conventional Mining of Pitching Seams
Many methods are used for underground mining of pitching anthracite in
Pennsylvania. The design is usually adapted to the particular seam
conditions but all are variations of the traditional gangway, chute,
and heading method of mining. The coal is drilled and blasted in a
rectilinear grid of pillars, headings, and entries (or breasts as they
are called in the Pennsylvania anthracite fields) oriented with the
strike and dip of the seam. If the pitch of the seam is not sufficient
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for the coal to “run” by gravity, scraper loaders are the device
typically used to gather .ind load the broken coal for transport.
Induced Caving
For more than 20 years induced caving has been considered
as a feasible mears for wining steeply pitching anthracite beds LI
//Allan, Andrew, Jr and P. S. Davies (1953) Recovery of Anthracite In
A Steeply Pitching Bed By Induced Caving, U. S. Bureau of Mines Report
of Investigations 5013, 12 p.
The system (see Figure attached) is generally similar to metal mine
caving and is worked up the pitch so that broken coal will flow
through inclined chutes to the gangways, which are driven horizontally
parallel to the strike of the coal bed. The system is reported to
result in increased production and coal recovery combined with
improved underground safety. Mining costs were said to be low due to
high production per worker (30 to 40 tons per man shift), less
development and operating cost, and higher productivity per hour per
unit of work area. The method would appear to be best suited for very
0
steeply pitching veins (at least 45 ) preferably 60 degrees or greater)
where top rock is more likely to remain intact without support pending
backfilling.
Rydraulic Mining
Hydraulic mining uses water under very high pressure through
controlled nozzles and should be especially applicable in wet mines
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where availability of water is not a problem and where seam dip is
sufficient ‘(more than 70) for the ‘water-coal mixture to flow to
collection areas whe’re the roof and floor are reasonably strong, the
seam is thick (more than 5 feet, and the thicker the better), and
the coal is relatively friable. From what is known to date much of
the Narragansett coal would fit these criteria.
The Bureau of Mines began research on hydraulic coal mining
in 1958 and has reported on the results
‘/ Maleflka, W. T. (1968) Hydraulic Mining of Anthracite Analysis of
Operating Variables)U. S. Bureau of Mines Report of Investigation 7120,
19 p.
An average cutting rate of 0.952 tons per minute was achieved, and
since then the process has been installed commercially. At the Sparwood
Mine of Kaiser Resources Ltd in western Canada, productivity rates of
90 tons per man shift were achieved in steeply—dipping bituminous coal.
While Narragansett anthracite may not be as perfect for hydraulic mining
as the Sparwood coal due to presence of slate partings within the
anthracite, it otherwise appears to be an excellent candidate for
extraction using such techniques.
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A recent patent (# 4,023,862) was issued to substitute oil
for water in the hydraulic mining process. The patent contemplates
automated underground mining using heated oil under high pressure
permitting a coal-oil slurry to be pumped to the surface. The patent
was granted to Dr. Louis S. Gold of Biopolis Corporation of America,
Washington, D.C.
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Longwall Mining and “Roadheaders ”
The Bureau of Mines has conducted research on ion gwall mining
of anthracite beds dipping as much as 35 degrees or more. j/ 4i
j/ Malenka, hi. T. and R. J. Brennan (1966) Experimental Longwall Mining
In A Pennsylvania Anthracite Mining - Use of A Shearer Loader. U. S.
Bureau of Mines, Report of Investigation 6745. 12p.
Brennan, R. J., J. W. Buch, and E. R. Novrocky (1964), ExperiwEntal
Ion gwail Mining In A Pennsylvania Anthracite Mine - Use of Yielding
Steel Props, U. S. Bureau of Mines Report of Investigation 6378, 27p
Successful ion gwaii mining was accomplished and, during the experimental
period appeared to offer increased productivity over the conventional
rectilinear pillar and entry system. Crawler-mounted “roadheader”
equipment would be used during development for tunnels and to create first
cuts for the longwall machinery. For pitches of not more than 20 degrees,
“roadheaders” themselves are capable of mining the coal by any of several
mining methods. In fact, it would seem plausible that “roadheader”
equipment could be adapted to mine under more steeply pitching
conditions (up to 30’ ). Such machines are inherently very efficient
and versatile. They are, essentially, very powerful crawler-mounted
continuous mining machines with a ripper—cutter head mounted on a
wide—ranging boom. Production rates of 35-70 yards per hour are
given for use in coal.
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Aj gering and Boring
The Bureau of Mines also has been studying the use of various
boring and augering techniques for mining anthracite in steeply pitching
searns.j/ / Various equipment types and configurations have been
Travenner, W. H. and J. T. Schimz,el (1966) Use of a Continuous Borer
In Mining Pitching Anthracite Beds, U. S. Bureau of Mines Report of
Investigations 6759, 25p.
, / Schimmel, J. T., W. H. Travenner, and Donald Markle, Jr. (1962) Use Of
A Large-Diameter Auger In Mining Pitching Anthracite Beds, U. S. Bureau
of Mines Report of Investigations 6135, 24 p.
used to mine both from the surface and from underground workings, the
rate of productivity sought is in excess of 10 tons per man shift in
beds pitching 15 degrees or more. Equipment capability sought for,
includes boring to distances of at least 300 feet in coal, both up dip
and down dip.
In Situ Gasification
Underground or “in place” (in situ) conversion of coal to
gas is achieved by controlled combustion of coal in the presence of introduced
and designed quantities of air, steam—air, oxygen, or steam-oxygen
gasifying agents. The method saves mining costs involved in above ground
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gasification and is ecologically appealing. However, it is a
difficult process to regulate and monitor particularly in non-uniform
coal beds. Gas produced is generally of poor or variable quality
and even combustion and gas productivity is difficult to sustain.
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CONCLUSIONS
If economically minable-sized blocks of coal are established
to exist in the Narragansett Basin, several appropriate methods are
available for extracting such coal, and extracting it in an
environmentally compatible fashion.
Review of several available mining techniques leads to the
conclusion that induced caving, longwall, roadheader, and hydraulic
mining offer the greatest potential for future Narragansett Basin coal
mining. The techniques promise low cost and high coal recovery
in pitching beds. If such methods are practiced in conjunction with
proper back stowage of mine and mill wastes, subsidence and other
surface effects should be minimized.
Mining costs cannot be determined exactly prior to mine model
design-cost engineering studies. Such studies, in turn, wo jld not be
valid until sufficient favorable reserve data are available to
permit the reasonable planning of viable operation However,
the suggested mining methods should offer mining costs that compare favorably
with the average cost of $13.32 (in 1972 dollars) per ton estimated
for Pennsylvania anthracite mined by conventional methods. 7j
/ Berger Associates and A. B. Riedel Associates (1975) Evaluation of Mining
Constraints to the Revitalization of Pennsylvania Anthracite. U. S. Bureau
of Mines Open File Report 47—75 on Contract # S0241039. 375 p. (available
through NTIS document # PB-242-580.
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