The following summary was extracted from an extensive report on the coalbed methane resource potential of the Richmond Basin prepared by the Department of Mining and Minerals Engineering, Virginia Polytechnic Institute and State University. E33 METWE POTENTIAL FROM COAL SEAMS fN THE RICHMOND BASIN OF VIRGINIA Final Report March 1981 Frepared by Department of firiing and Minerals ,Engineering Virginia Polytechnic Ins titutE and Stare University Blacksburg, Virginia 24061 under -TRW Subcontract No. HP2176JJ9S ' 'WE C-mtsact NQ D.E-AC21-78MCO8089 for TRW Energy Systems Group 8301 Greensboro Drive McLean, Virginia- 22102 Reprinted with permission of the Department of Mining and Minerals Engineering, Virginia Polytechnic and State University. This report is an evaluation of the coalbed methane resource potential of the Richmond Basin in east-central Virginia. The work was conducted and the report prepared by the Department of Mining and Minerals Engineering, Virginia Polyeechntc Institute and State Uni- versity under TRW/WI & SU Subcontract R12176JJ9S, a subcontract under the U.S. Deparment of Energy (DUE) Methane Recovery from Coalbeds Project administered by the Morgantown Energy Technology Center. The work develops the geologic framework and the coal and coalbed methane resources in a geologic .basin from which very little recent subsurface exists. This report provides the background OR which future coalbed methane explorztion programs in this basin can be deveioped. The Richmond Coal basin, locared abour: 12 miles west of the cis? of Richmond, Yirghia,vas the site of the first commercial coal mining in the Uniced States. ?fining activity continnu'ed rhese for a period of about 200 years. bespite chis long histcry of mining activity, it is .estimated t'Mt total produc:ion from tne basin only- amounted to about eight million tons of coal. Because very limited exploration work vas done, the full exrEnL of the coal resources of the basin are un- known and resource estimares are tberef ore imprecise , alrhaugt.1 Khey appear to range from 'two to four billion tons. The coal is chiefly medium volatile bi:uminous and in some ereas h2s been altered to coke by igneous intrusions, From the records, ir appears that the coals contain significanc quantities of methane. Alchough numerous reports of gas, gas explos- ions and disasters are recorded, acegrate measurement ~f the gas con- tent has never been attmpted to establish the potential of this resourct. The city of Richmond, which currently consumes 13 bFllion cu. ft. per year of natural gas (Lordley, 19791, provides an excellent outlet and market for methane gas which may be produced from the besin. Geologiczllp, the coal occurs in 2n elongated basin 33 miles from north to south with a width that varies up to 9.5 miles. As scared, exploration has been minimal and the actual proportian of this area of approximztely 170 square miles underlain by coal is not known. However, coal does outcrop ar is known to occur mer 2 distance of about 32.4 miles of a total perimeter of some 70 miles. 0 0 The coal seams dip steeply at 15 - G5 touards the center af the basin. The deepest part of the basin,ar: whi;h coal is known to exist, vas sampled at the Salisbury borehole L+ich intercepted coal at 2320 feet (Jones, 1928) The depth in the center of the basin is not , knom, but could be 3,000 feet or greater. Whether or not the coal is continuous across the basin or ccnrinues around the per: 1 metes CaIXlQK be detemined from present widence. The ma!. seams mines, ranging from three to five in nuinber, achieved great thicknesses especially where t~oor more of the seams merged. Thicknesses of 70 feet of coal, with some included shale bands, have been recorded. As a result, assumptions have been made of rhe extent and thick- ness or' the coals, upon which a c021 resource has been es:imared by computer conceuring of available values, which resul~sin B conser- vative estirnare of 2.3 billion tors. The reyrr of Sh2ler and Woodworth (1899) indicates the recoverable coal Teserves ar 1.152 billion tons, which when adjusred LO include the unrecovereble coal gives a resource of 2.1 billion tons. Resource esrimarred by Heinrich (1878) range from 1.987 to 3.887 billion tons. In this report, how- ever, a more conservative estimzte of two billion ton5 has been used for the calculacions of the methane conrenr. These resources were concourgd for depth and thickness of caal, and an average quality of the coal wa5 calculated. The results,based on the available data pertaining ch-ier‘ly t5 the perimeter vhich was mined, are of varying credibility because of the quality dates and origin of some of the reports. For this rezson, the gas content has been estimated using the method of W (19771, and the result has been evzluared for csedkbility with the reports of methane g+s and found to have no conflict. From this study it would appear that the potentialresource methane may range from 700 billien cu. ft. tolGOO billion cu. ft. or enough to provide many years supply based upon the current ‘tat21 usage rate of Richmond. Therefore, the drflling of 2 nuaber of exploratory holes in the bash may have merit EO establish the actllzl exfenr of the coal beds, the merhane content of these Sed5,and the characteristics of desorp- tion of the methane gas from the beds. GUIDEBOOK TO THE GEOLOGY OF THE RICHMOND AND TAYLORSVILLE BASIN, EAST-CENTRAL VIRGINIA By Bruce K. Goodwin1, Robert E. Weems2, Gerald P. Wilkes3, Albert J. Froelich2, and Joseph P. Smoot2 Eastern Section AAPG Meeting Fieldtrip Number 4 10 November 1985 1 College of William and Mary, Williamsburgh, VA 23185 2 United States Geological Survey, Reston, VA 22092 3 Virginia Division of Mineral Resources, Charlottesville, VA 22903 The following guidebook, prepared by Dr. Bruce K. Goodwin and others in 1985 for the Eastern Section Meeting of AAPG, was available for many years from the Virginia Division of Mineral Resources in Charlottesville, VA. It is reproduced herein, with permission of the Division, to replace the now out-of- print version of the guidebook. Content s Introduction and regional setting ........................... 1 Areal extent and geologic setting ........................... 3 Previous work............................................... 9 Stratigraphy ................................................ 9 Stratigraphy of the Richmond basin ..................... 10 A brief history of coal mining in the Richmond basin. .. 12 Stratigraphy of the Taylorsville basin ................. 14 References cited............................................. .. 16 Road log .................................................... 19 Taylor svi 1 le bas i n Stop 1 -- Doswell Formation, Stagg Creek Member and Falling Creek Member........................ 19 stop 2 -- DoswelI Formation, Newfound Member..,.,..... 28 Stop 3 -- Doswell. Formation, Newfound Member........ .. 30 Stop 4 -- Doswell Formation, Newfound Member .......... 32 Ri chmond basin Stop 5 -- Petersburg Granite and Tuckahoe Group, lower barren beds............. .............. 35 Stop 6A -- Chesterfield Group, Vinfta Beds........,.... 40 Stop 6B -- Chesterfield Group, Vinita Beds............. 43 Stop 7 -- Tuckahoe Group, productive coal measures.... 45 Stop 8 -- Chesterfield Group, Otterdale Sandstone ..... 54 F i gur es 1 -- Exposed basins of the Newark Supergroup in eastern North America......................................... 2 2 -- Regional geologic setting of the Richmond and TayPorsville basiRs ................................... 4 3 -- Generalized geologic nap of the Richmond basin and outlying basins.., .................................... 5 4 -- Geologic map of the exposed portions of the Taylorsville basin .................................... 6 Figures [continued) 5 -- Stratigraphic columns of the Richmond and TaylorsviIle basins.....................*..............- 8 6 -- Generalized map of the geology surrounding the Richmond and Taylorsville basins, also showing the status af 7.5-minute geoIogic quadrangle mapping in both basins...................................,..,.... IS 7 -- Map showing detailed location of Stops 1 and 2 in the Hanover Academy ?.5-rninute quadrangie ............. 20 8 -- Columnar section of Outcrop A at Stop l............... 22 9 -- Columnar section of Outcrop B at Stop I............... 27 10 -- Diagramnatic portrayal of Outcrop C at Stop 2..... .... 29 11 -- Map showing detaiIed location of Stops 3 and 4 in the Ashland 7.5-minute quadrangle ..................... 31 12 -- Geologic map of Stop 5 and vicinity ................... 36 13 -- Generalized geologic section of the Triassic rocks exposed in the Boscobel Quarry.. ...................... 38 24 -- Geologic nap of Stop 6 and vicinity. .................. 41 15 -- Geologic map of Stop 7 and vicinity ................... 46 16 -- Sketch map of the exposed coal beds and basin margins near Midlothian, and hypothetical cross sections across the basin margins .............................. 47 17 -- Geologic map of Stop 8 and vicinity ................... 55 GUIDEBOOK TO THE GEOLOGY OF THE RICHMOND AND TAYLORSVILLE BASINS, EAST-CENTRAL, VIRGINIA After the Appalachian orogeny, the long period from Permian through Early Triassic time was dominated by erosion and nondeposition in eastern North America. This interval was succeeded by an early Mesozoic rift regime, apparently controlled by extensiond forces, that eventually would open up the AtIantic Ocean basin. One of the earliest signs of this profound change in tectonic regime was the commencement of