Availability of coal resources for mining in Illinois : Middletown Quadrangle, Central Illinois

56 Pages·1994·3.3 MB·English

by  Treworgy, Colin G

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Qpjji^iuj^x^
Coal Resources
Availability of
Mining
for in Illinois
Middletown Quadrangle, Central Illinois
Colin G. Treworgy, Gayla K. Coats, and Margaret H. Bargh
Circular554 1994
DepartmentofEnergyand NaturalResources
ILLINOISSTATEGEOLOGICALSURVEY
1905
LIBRARY.
ILLINOISSTATEGEOLOGICALSURVEY
3 3051 00002 8773
Availability of Coal Resources
Mining
for in Illinois
Middletown Quadrangle, Central Illinois
Colin G. Treworgy, Gayla K. Coats, and Margaret H. Bargh
<#v
*V
Circular554 1994
ILLINOISSTATEGEOLOGICALSURVEY
MorrisW. Leighton,Chief
Natural Resources Building
615 East PeabodyDrive
Champaign, Illinois 61820-6964
Coverphoto Generalextent,depth,andthicknessoftheSpringfield
CoalinIllinois. Region3andtheMiddletownQuadrangleareoutlined.
PrintedbyauthorityoftheStateofIllinois/1994/1200
Sprintedonrecycledpaper
CONTENTS
ABSTRACT
1
INTRODUCTION
1
Investigations ofAvailableCoal Resources 1
Framework forStudies ofAvailableCoal in Illinois 3
Geologicand PhysiographicSetting ofRegion3 3
Previous Investigations ofCoal Resources in Region3 4
Coal ResourceClassificationSystems 4
GEOLOGYOFTHE MIDDLETOWNQUADRANGLE
11
Glacial Deposits 11
Bedrock Stratigraphy 11
Chapel Coal 11
WestFranklin Limestone 11
DanvilleCoal 11
Anvil RockSandstone 11
Brereton Limestone 21
HerrinCoal 21
St. David Limestone 21
Turner MineShale 21
Springfield Coal 21
ExcelloShale/HouchinCreekCoal 21
SurvantCoal 21
ColchesterCoal 21
"Seahorne coal" 21
Structure 21
LANDCOVERANDOTHERFEATURESOFTFIE MIDDLETOWNQUADRANGLE 27
MINING HISTORY 27
FACTORSAFFECTING THE AVAILABILITYOFCOAL 27
Surface MinableCoal 30
Thickness ofcoal 30
Thickness ofoverburden 30
Stripping ratio 30
Land cover 30
Size and configurationofminingblock 31
DeepMinable Coal 31
Thickness ofcoal 31
Depth ofcoal 31
Thickness and composition ofbedrock overburden 32
Floor conditions 32
Roofconditions 32
Clastic dikes 35
Size and configurationofminingblock 35
Thickness ofthe interval between seams 36
Destructionofresourcesby orderofmining 36
Land cover 36
Coal Quality 36
COAL RESOURCESANDAVAILABLE COAL INTHE MIDDLETOWNQUADRANGLE 36
Common Resource/Reserve Classifications and AvailableCoal 37
Identified resources 37
Demonstrated reservebase 37
High development potential 39
Chapel Coal 39
DanvilleCoal 39
HerrinCoal 40
Springfield Coal 40
ColchesterCoal 40
"SeahorneCoal" 40
EffectofMiningMethod on AvailabilityofCoal 40
IMPLICATIONS FORTHE AVAILABILITYOFCOAL RESOURCES INREGION3 41
SurfaceMinable Resources 41
Deep Minable Resources 42
CONCLUSIONS
47
ACKNOWLEDGMENTS
47
REFERENCES 47
TABLES
1 Range oftypical analyses oftheSpringfield Coal on anas-receivedbasis 36
2 Criteria used to defineavailablecoal resourcesin the MiddletownQuadrangle 37
3 Original and remaining resources and available coal in theMiddletownQuadrangle 38
4a Available surfaceminable resources, according to typeofrestriction 40
4b Available deep minableresources, according totypeofrestriction 41
FIGURES
1 Coal resource regionsand proposed quadranglesforcoal availabilityassessments 2
2 Remainingcoal resources, indicated by region 3
3 Historical record ofcoal production, indicated by region 3
4 1991 coal production 3
5 Thickness ofPleistocene deposits inIllinois 5
6 Topography ofthebedrock surface inIllinois 6
7 Elevationofthe top ofthe HerrinCoal 7
8 General extent, depth, and thickness oftheSpringfield Coal inIllinois 8
9 General extent, depth, and thickness ofthe HerrinCoal in Illinois 9
10 Distribution ofdata points and crosssectionlines used in this study 10
11 Selected stratigraphic units present in theMiddletownQuadrangle 11
12 Thicknessofthe PennsylvanianSystem in Illinois 12
13 Elevationofthebedrocksurface inthe MiddletownQuadrangle 13
14 Cross section 1-1' 14
15 Cross section2-2' 14
16 Crosssection3-3' 14
17 Cross section A-A' 15
18 Cross sectionB-B' 15
19 Cross sectionC-C' 15
20 Thicknessofglacial sediments in theMiddletownQuadrangle 16
21 ThicknessoftheChapelCoal intheMiddletownQuadrangle 17
22 ThicknessoftheWest FranklinLimestone in the MiddletownQuadrangle 18
23 Thicknessofthe DanvilleCoal intheMiddletownQuadrangle 19
24 Thickness ofoverburden ofthe DanvilleCoal inthe MiddletownQuadrangle 20
25 Thicknessofthe HerrinCoal in theMiddletownQuadrangle 22
26 Thicknessofoverburden ofthe HerrinCoal in theMiddletownQuadrangle 23
27 ThicknessoftheSpringfieldCoal in theMiddletownQuadrangle 24
28 Thickness ofoverburden oftheSpringfield Coal inthe MiddletownQuadrangle 25
29 Thickness oftheColchesterCoal in theMiddletownQuadrangle 26
30 Thickness ofthe "Seahorne coal" in theMiddletown Quadrangle 26
31 Elevationofthe top oftheSpringfield Coal in the MiddletownQuadrangle 28
32 Selected featuresoftheMiddletownQuadrangle 29
33 Thicknessofbedrockcover over the HerrinCoalin theMiddletownQuadrangle 33
34 Thickness ofbedrockcover over the Springfield Coal in theMiddletownQuadrangle 34
35 Availability ofcoal resources intheMiddletownQuadrangle 38
36 Factors restricting the availability ofsurface minable coal in the MiddletownQuadrangle 38
37 Factors restricting theavailabilityofdeep minable coal in the MiddletownQuadrangle 39
38 Availability ofHerrinCoal resources forsurface mining 43
39 AvailabilityofHerrinCoal resources for deep mining 44
40 AvailabilityofSpringfield Coal resources forsurface mining 45
41 AvailabilityofSpringfield Coal resources fordeep mining 46
ABSTRACT
Many of the geologic and physiographic conditions No surface minable resources are available and
common to west-central Illinois are found in the Mid- only 58% of the original deep minable resources (55%
dletown Quadrangle, the focus of this report. It is the ofthe original total) are available for mining. Ifunder-
firstofaseriesthatwillexamine theavailabilityofcoal ground mining is restricted to room and pillar tech-
resources for development in Illinois. niques (thus excluding longwall mining), unfavorable
Environmental and regulatory restrictions, socio- roof and floor conditions reduce the amo—unt of avail-
cultural features (towns, highways), mining technolo- able resources to a low 195 million tons 51% of the
gy, geologic conditions, coal quality, and economic total original resources.
conditions all affect resource availability. Interviews Technologicalfactors,includingbedrockandseam
with experts from coal companies and state govern- thicknesses as well as roof and floor conditions, ac-
ment indicated how these various geologic and land count for 98% of the unavailable tonnage. Land use
use conditions restrictmining. restrictions due to towns, interstate highways, mines,
Coal resources and related geologic features were cemeteries,andothersocioculturalfeaturesaccountfor
described and mapped forthis report.Originalresour- theremaining2%ofunavailabletonnage.Thesefactors
ces for the six seams underlying the quadrangle total probably also restrict the mining ofsignificant quanti-
385milliontons;383milliontonsremainintheground, ties ofcoal resources elsewhere incentral Illinois.
and 211 million tons are estimated to be available for Consequently, the amount of coal available for
mining. developmentintheMiddletownareamaybeconsider-
ably lower thanhasbeenindicated by earlier studies.
INTRODUCTION
Accurate estimates of the amount of coal resources Bargh (1982) conducted a similar examination ofdeep
availableforminingareneededforplanningbyfederal minable resources in the state. The latter study ranked
and state agencies, utilities, and other energyconsum- coal into four categories of development potential:
ers and producers. Inventories ofcoal resources inIlli- high, moderate, low, and restricted. Deposits with a
nois are relatively accurate estimates of the total high potential for development had characteristics
amount of coal in the ground. There is serious doubt, similar to deposits currently being mined; whereas
however, regarding the percentage of coal resources those with moderate or low potential had less favor-
thatcan actuallybe mined. Environmental and regula- able characteristics. Restricted deposits were consid-
tory restrictions, the presence of towns and other cul- ered unminable because of constraints due to surface
tural resources, current mining technology, geologic land use oroil fields.
conditions, coal quality, and other factors significantly As thesetwostudiesdemonstrated,alargeportion
reduce the amountofcoal available for mining. of the state's coal resources have characteristics that
This Middletown Quadrangle report is the first of restrict their development potential. Because of the
a series in which the Illinois State Geological Survey statewide approach used in these studies, however,
(ISGS) will examine the availability of coal resources manyfactorsthatrestrictthedevelopmentofcoalwere
fordevelopmentinthestate.TheMiddletownareawas not considered; for example, the geology of roof and
selected as representative ofmany of the geologic and floor strata, thickness of the interval between seams,
physiographic conditions in west-central Illinois. Coal and thickness of the bedrock overburden. The actual
resources and related geologicfeaturesweredescribed amount of available coal may thus be significantly
and mapped. Miningexpertsfromcoalcompaniesand lowerthanindicatedby theinitialestimates. Treworgy
state government were interviewed for information etal. (1978)estimated that6billionofthe20billiontons
about how various geologic and land-use conditions of surface minable resources are suitable for mining.
mightrestrict mining ofthese deposits. Industry sources have suggested that the amount of
surface minable coal available is actually much lower.
Investigations of Available Coal Resources The steady decline since about 1970 in the number of
The difference between estimates of Illinois' total coal surface mines in the state (down from 35 to 15 mines)
resourcesand theportionoftheresourcesavailablefor and the annual percentage of the state's total produc-
development was discussed as early as 1969 by Risser tion from surface mines (down from 51% to 26%) ap-
and later by Attanasi and Green (1981). Zwartendyk pears toconfirm this view.
(1981) described this difference as a major problem In 1987, the National Coal Council concluded that
with all estimates ofmineral resources. lackofinformationon theavailabilityofcoalresources
Recognizing the need for estimates of available isanationwideproblem thatshouldberectified. In the
coal,Treworgyetal. (1978) used a relativelysimpleset late 1980s, the U.S. Geological Survey (USGS) began
of criteria to make a general, statewide assessment of sponsoring assessments of the availability of coal
surface minable resources in Illinois. Treworgy and resources in eastern Kentucky (Eggleston et al. 1988,
imit of
Pennsylvaliian
Danville
Lawrsriceville
Figure 1 Coal resource regions and proposed quadrangles for coal availability
assessments.
1 2 3 4 5 6 7
Region
Figure 2 Remainingcoalresources. Figure 3 Historical record of coal production.
Carter and Gardner 1989). These studies have since
25
beenexpanded to include WestVirginia, Virginia,and
Ohio (Jake 1989,Carteretal. 1990, Sites etal. 1991). Surfacemines
TheUSGS-sponsoredstudiesexamineindetailthe 20 - Underground mines
factors affecting the availability of coal for mining
within a 7.5-minute quadrangle (about 56 square v>
miles). The relatively small study areas permit more I 15
complete and comprehensive data collection and as-
sessment thanispracticaloreconomical toconductfor I
10
a larger area (Eggleston et al. 1990). The quadrangles
selected represent the geology and mining conditions
found in surrounding quadrangles, and the results of 5 -
these detailed investigations can be used to estimate
the availability ofcoal resources intheseregions.
Framework for Studies ofAvailable 3 4 5
Region
Coal in Illinois
The results from the study of the Middletown Quad- Figure4 1991 coalproduction.
rangle, along with the results from the assessments of
available coal inother quadrangles, will beextrapolat-
ed to larger regions of Illinois. This research will pro- Geologic and Physiographic Setting of Region 3
vide a basis for updating, refining, and expanding The Middletown Quadrangle represents many of the
earlier work by Treworgy et al. (1978) and Treworgy geologic and physiographic conditions found inwest-
and Bargh (1982). These quadrangle studies will pro- central Illinois (region 3). The quadrangle is located
vide complete, up-to-date documentation of the crite- about 12 miles north of the city of Springfield (fig. 1).
ria for determining available coal in the state. The Flat, highly productive farmland covers thebroad up-
criteria will be sufficiently detailed to account for re- lands, which are dissected by relatively narrow zones
gional variations in geology and physiography that of gently rolling pasture and woodland along the
affect miningpractices. streamsand rivers.
The Illinois coal field was divided into seven re- About 3% of the land in region 3 is covered by
gions,whichservetoguidetheselectionofstudyareas towns or other development. The remainder is farm-
(fig. 1). Although the boundaries of the regions are land, pasture, water, woods, and wetlands. Excluding
somewhat arbitrary, each region represents a distinct Springfield and Decatur, the only extensive urban ar-
combination of geologic and physiographic charac- easinthisregion,onlyabout1%ofthearea isoccupied
teristics. Significantquantitiesofcoal resourcesremain by towns. There are more than 100 state parks and
inall regions (fig. 2). All regions havehad a significant naturalareasinthisregion.Aboutone-thirdoftheselie
amount of production (fig. 3), and all but region 1 outside of the area of coal-bearing strata. With a few
currentlyproducesomecoal (fig.4).Two tofourquad- minor exceptions, areas in which extensive drilling for
rangles in each region will be selected for an assess- oiland gasmayimpactcoal miningarerelativelysmall
ment of available coal resources. This number of and confined to eastern Sangamon, southwestern Ma-
quadrangles should be sufficient to evaluate the full con, and northern ChristianCounties.
range ofminingconditions in a region.
Throughout region 3 and central Illinois, the bed- Deep minable coal resources in this region were
rock surface is concealed by a thick layer of glacial mapped by Treworgy and Bargh (1982). Their study
depositsconsistingofclay,silt,sand,andgravel(fig.5). evaluated these resources with respect to thickness,
The bedrock surface is dissected by a well developed, depth, proximity to areas densely drilled for oil, and
preglacial drainage system (fig. 6). Glacial depositsare selected categories of surface land use (towns, inter-
lessthan50feetthickonthepreglacialuplandsurfaces state highways, public lands, cemeteries). Ofthe more
and more than400 feet thick where they fill major bed- than 28 billion tons of deep minable resources in the
rockvalleys. Thebedrockstrata dip southeastata low region, almost 63% (including almost all resources in
angletowardsthesouth-centralpartofthestate(fig.7). theMiddletownQuadrangle) were ranked ashavinga
The major geologic structures found in this region high potential for development. Other factors remain
arebroad anticlinesanddomes;someofthedomesare to be evaluated, however, including thickness and
used for storage of natural gas. There are no known composition of strata between seams, recovery ofcoal
major faultzonesintheregion. Astrike-slip fault,pos- above or below previously mined areas, proximity of
sibly traceable for several miles, has been reported in channelsandfaults,partingsandclasticdikesinseams,
Macoupin County (Nelson and Nance 1981). Minor roof and floor conditions, size and configuration of
faults that have a few feet of displacement have been miningblocks,and thickness ofbedrock overburden.
observed in mines in the region (Krausse et al. 1979,
Nelsonand Nance 1981, DeMarisand Nelson 1990). Coal Resource Classification System
Region 3 is underlain by several widespread coal TheISGSfollowsthetermsanddefinitionsoftheUSGS
seams that range from a few inches to7feetthick. The coal resource classification system (Wood et al. 1983).
coalsareshallowenoughtobesurfaceminableinareas Withminormodificationstosuitlocalconditions,these
where they crop outbelow the glacial deposits. Away definitions generally provide a standardized basis for
from the subcrops, the major coals are generally less compilations and comparisons of nationwide coal re-
than 600 feet deep. The Springfield Coal (informally sources and reserves. Some ISGS publications written
knownastheNo.5Coal)isthethickestseaminthearea priortothedevelopmentofthisclassificationsystemin
just south of the city of Springfield northward (fig. 8). 1976usetermsinamannerdifferentfromtheircurrent
Thiscoalhasbeenminedatseveral locations.TheHer- definitions. For example, the term "reserves," as used
rin Coal (informally known as the No. 6 Coal) is the by Smith (1961) is comparable to the term "resources,"
state's largest coal resource; itis best developed south asnow defined.
of the city ofSpringfield (fig. 9). North of the city, the Other ISGS studies have used terms that are not
Herrin Coal is thinner and more variable in thickness; part of the USGS system. As previously noted, Tre-
itisthickenoughtomineonlyinsmall,lenticularpods. worgyand Bargh (1982) created aclassificationtorank
Other coal seams, including the Chapel (formerly No. the potential for development of coal deposits in Illi-
8),Danville (formerlyNo. 7),HouchinCreek(formerly nois.Theircategoriesofhigh,moderate,andlowdevel-
Summum or No. 4), Survant (formerly Shawneetown opment potential are roughly equivalent to the USGS
orNo.2A),andColchester(formerlyNo.2),arepresent categories of economic, marginally economic, and
in this region; but they are generally too thin to be subeconomicreservebase.
economicallymined. Theterm"availablecoal"isalsonotaformalpartof
the USGS system, although commonly used by the
Previous Investigations of Coal in Region 3 USGS, the U.S. Bureau ofMines, and many State Geo-
Smith (1961) and Nance and Treworgy (1981) mapped logical Surveys. Eggleston et al. (1990) described the
coals thatwere surface minable (1.5 feet thickormore, rationale and general methodology for estimating
and less than 150 feet deep). Because of the lack of available coal, but did not explain the relationship of
outcrops and drilling data, these studies included no available coal to the formal categories of the USGS
mapping of surface minable resources in the Middle- resource classification system. Inthis study, "available
townQuadrangle. coal" is considered tobe equivalent to the reserve base
The availability of surface minable resources in and inferred reserve base categories of the USGS sys-
region 3 was partially evaluated by Treworgy et al. tem. Available coal is also roughly equivalent to the
(1978). Their study demonstrated how factors such as high and moderate development potential categories
strippingratio,sizeandconfigurationofminingblock, usedbyTreworgyand Bargh (1982).
and certain categories of surface land use limit the Available coal, as used in this report, is not meant
availability of surface minable resources. Of the more to imply that particular coal deposits can be mined
than 2 billion tons ofsurface minable resources in the economically at the present time. Rather, the term is
region, less than 13% were found to be suitable for used to designate deposits that have no significant
mining. Several significant factors were not evaluated characteristics likely to render them technically, le-
in that study, including average stripping ratios of gally, or economically unminable for the forseeable
mine blocks, loss ofresources inminor seamsbecause future. Furtherengineering assessments are needed to
of preferential mining of thicker, underlying seams, determine the actual cost and profitability of mining
and proximity ofmineblocks to towns and important thesedeposits.
natural areas.