BOARD02292

• Board Meeting Date: 3/29/1999
• Description: Directors' Reports
• Board Meetings - Doc Type: Memo

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decrease in the value of gas produced. The report is expected to be completed and published in April.

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NEW COAL REPORTS: The CGS has published two new coal reports.

The first report, published in cooperation with the U.S. Department of Energy, is called "Demonstrated
Reserve Base for Coal in Colorado: the Somerset Coal Field" (Open File Report 98-5). The report
contains a new estimate of the Demonstrated Reserve Base (ORB) of the Somerset coal field in the
Piceance Basin in Gunnison County. The new ORB estimate is 3,180 million tons. The accessible reserve
base, which excludes coal restricted by land use or technological considerations, is estimated to be 2,400
million tons. Estimated recoverable reserves are 1,280 million tons, about 40 percent of the ORB.

A second report, prepared in cooperation with the U.S. Geological Survey, also estimates the amount of
available coal in the Somerset quadrangle of the Piceance Basin ("Availability of Coal Resources in
Colorado: Somerset Quadrangle, West-Central Colorado," Resource Series 36). This report estimates the
available coal accessible for mine development under current regulatory, land use and technological
constraints. This study indicates that approximately 2,236 million short tons of the total 3,088 million
tons (about 75 percent) is available for development. Approximately 75 million tons of coal has been
mined in the area, and about 275 million tons o[coal has been lost through mining. Coal loss includes
coal unavailable to be mined due to previous mining of adjacent beds or mining of coal within the same
bed. The report also contains historical coal production data from the active and historic coal mines of
the region.

REPORT OFFERS INSIGHTS INTO MINING STRATEGIES: The CGS has released a new
bulletin on "Clastic Dikes Intruding Cretaceous Coals of Western Colorado," Bulletin 53. Studies of
clastic dikes are important because they can create severe problems in coal mines that may result in .
injury of mine workers and increased cost resulting in mine closure. Clastic dikes are often more
permeable than the surrounding coal beds and offer avenues for coal bed methane migration creating a
potential for fire and poisonous gas problems at the mine face.

Clastic dikes are formed in certain geological environments soon after the deposition of coal beds. The
dikes are composed of sand and other fine-grained material that were injected into the adjacent coal beds
effectively replacing the coal beds. Clastic dikes are widespread in western Colorado coal fields and are
particularly abundant in southern part ofthe Piceance Basin near the towns of Somerset and Palisade.

SEDGWICK COUNTY RESOURCE POTENTIAL: The CGS has released an evaluation of the
mineral and mineral fuel resource potential of the 32,550 acres of state mineral lands located in
Sedgwick County as part of its long-term evaluation of 4,000,000 acres of state lands administered by the
State Land Board. The CGS divided these lands into 30 individual tracts ranging in size from 480 acres
to 7,680 acres for evaluation purposes. This report includes a general summary of the geology and
mineral potential of Sedgwick County along with maps of state trust land locations, oil ands gas tests,
and industrial mineral prospects. The main body of the report is an evaluation of each individual tract.

NEW REPORT DESCRIBES COLORADO MINING DISTRICTS: The CGS has released a new
report on mineral deposits in Colorado, "Alkalic Igneous Rocks of Colorado and their Associated Ore
Deposits" (Resource Series 35). The report contains descriptions of the geological setting, geochemistry,
economic geology, exploration and production history, and a reference list of the major mining districts
in Colorado that are associated with alkalic igneous rocks.

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