Coal Resource Recoverability
A Methodology

U.S. Bureau of Mines Circular 9368

ABSTRACT

This report presents a U.S. Bureau of Mines methodology developed to incorporate factors of coal production (mining and cleaning methods, recoveries, economics, etc.) into the definition of recoverability of a coal resource. Project procedures and computer models that were developed to include mine and preparation plant production rates, recoveries, and costs are explained. The results of these procedures and models are reviewed and compared to the Energy Information Administration estimate of U.S. coal resources- the "demonstrated reserve base." The Matewan 7-1/2-minute quadrangle in eastern Kentucky was selected to demonstrate the methodology.

INTRODUCTION

The availability and amount of coal resources in the United States has been debated for years. Past figures based on gross estimates of coal in the ground did not address the amount that might realistically be available for production after environmental and technological restraints are considered. Many technological, economic, and social changes have impacted the coal industry since the last U.S. Bureau of Mines comprehensive coal-reserve data were published in the 1970's (1-4).3 The Clean Air Act Amendments of 1990 to control sulfur dioxide and nitrous oxide emissions from coal-fired powerplants will significantly change the mining and marketing of coal. Legislation and regulations on mine reclamation have increased the complexity and costs of coal mining. Also, new safety and health standards, with their associated taxes, have increased the cost of mining operations. Advancements in mining technology in underground and surface operations have changed the economic competitiveness of certain coal fields (5-12).

Concerns about securing environmentally acceptable and reliable energy sources that have continually surfaced during the past 15 years have resulted in many revised estimates of the coal reserves in the United States (1-4, 13-14). The Energy Information Administration regularly updates its estimate of U.S. coal resources-the "demonstrated reserve base' (DRB)-with new information from State geological surveys and the U.S. Geological Survey (USGS). At the present time, the DRB is estimated to be about 475 billion short tons of coal (14). Even at consumption rates of 1.0 billion tons per year and a previously accepted recovery rate of 50%, there would appear to be ample available coal resources for several centuries. However, if the effects of mined-out prime reserves, and environmental, industrial, economic, and social considerations are assessed and the technical aspects of the minability and washability of the individual seams are considered, the amount of coal that would be available and economically recoverable would be far less than that stated in the literature (1-3, 14).

In 1986, the USGS and the Kentucky Geological Survey (KGS) began a Coal Availability study (15) of an area within the central Appalachian coal region-the Matewan 7-1/2-minute quadrangle-in order to determine the resources available for mining after environmental and technological restrictions were considered. Success from this pilot study allowed the USGS to include the geological surveys of Virginia and West Virginia in an expanded program encompassing most of the central Appalachian coal region (16).

In December 1988, the USGS requested that the Bureau review its Matewan quadrangle report and associated information, and determine if a joint study could result in the development of a new methodology that would incorporate coal mining and coal cleaning recovery factors and mine operating costs into the economic recoverability of a coal seam. Relative to that review were mine evaluations the Bureau conducted during the past 5 years to support U.S. Department of Commerce studies which compared the cost of coal mining in the United States to the cost of coal mining in selected foreign countries. This continuing work has provided a broad information base of mining conditions, equipment and workforce requirements, production rates, and capital and operating costs throughout coalfields in the United States. The Bureau decided to pursue the joint study with the understanding that the USGS and State geological surveys would provide geological and environmental maps and data, coal geology model data, and software usage training. In return, the Bureau would provide coal mining, cleaning, and costmodeling expertise in an effort to determine the amount of remaining recoverable coal and the costs to mine and process that coal and reclaim the mined land.

It was decided that the first area studied by the Bureau would be the same area first studied by the USGS-the Matewan quadrangle. The Matewan quadrangle lies on the Kentucky-West Virginia border, primarily in Pike County, KY (fig. 1). Only the Kentucky portion of the quadrangle (approximately 90% of the land area) was evaluated. Twenty-one coal seams were identified by the KGS to contain minable resources. The stratigraphic relationships, are shown in figure 2.

USGS COAL AVAILABILITY CONCEPT

Three pertinent steps were defined in the USGS Coal Availability study (16):

1. Study area selection.
2. Data collection nd assimiiliation.
3. Resource etimation.

Minabile coal was defined by the USGS Coal Availability study as follows:

ORIGINAL COAL RESOURCES
minus
COAL MINED AND COAL ABANDONED DURING MINING
equals
REMAINING COAL RESOURCES
minus
COAL RESTRICTED BY LAND USE CONSIDERATIONS
minus
COAL RESTRICTED BY TECHNOLOGICAL CONSIDERATIONS
equals
COAL AVAILABLE FOR MINING.

USBM COAL RECOVERABILITY CONCEPT

Following review meetings in Denver, CO, and Reston, VA, and preparation of a project outline, the authors conducted a preliminary recoverability and costing study of three Upper Elkhorn coal seams in the Matewan quadrangle. That preliminary evaluation showed excellent correlation with the USGS computer model for minable resources (98% agreement). Perhaps more importantly, however, the preliminary evaluation resulted in the establishment of an outline for the Bureau program methodology, as well as the development of recovery and costing models. The Bureau study incorporated the USGS methodology, reviewed the restrictions and modified the resources accordingly, addressed mining and recovery losses, and finally applied the mine operating economics. The following integrated pathway that resulted established a uniform, consistent methodology to be applied throughout the study:

COAL AVAILABLE FOR MINING
minus
MINING LOSSES
minus
WASHING LOSSES
equals
RECOVERABLE RESOURCES
restricted, by
MINE OPERATING COSTS
equals
ECONOMICALLY RECOVERABLE RESOURCES (RESERVES).

USBM PROGRAM OBJECTIVES

Realistic coal resource assessments are important for the consideration of legislation and regulations affecting coal production and for the direction and implementation of research aimed at maximizing recovery and ensuring environmental protection. Major national concerns that prompted the USGS-KGS Coal Availability program and the Bureau Coal Recoverability program are as follows:

1. Potential production disturbances in the world petroleum supply.
2. The rising requirement for low-sulfur (compliance) coal, as a result of the Clean Air Act Amendments of 1990, and the social and economic disruptions that occur as coal mining shifts from "traditional" high-sulfur coals of the East and Midwest to low-sulfur coals of the Western
   United States.
3. Growing recognition of the need to mitigate the environmental consequences of past, present, and future coal mining.
4. The need for accurate coal resource, recovery, and costing estimates that will contribute to relevant government policy decisions.
5. The need to determine mineral valuation and development potential of coal resources on public lands administered by the Bureau of Land Management and the National Forest Service.

The Bureau's minerals availability expertise and experience, gained in completing more than 70 detailed coal mine technical and economic assessments, and its active research role (coal mining, coal cleaning, mine safety, stability, resource recovery, equipment design, advanced mining methods, and economics) provide the background for this program. It was decided that the quadrangles studied by the Bureau would follow the USGS sequence.
The objective of the Bureau coal recoverability program is to address the following concerns:

1. Developing a methodology to calculate recoverable coal resources, and their associated mine operating costs, in the same areas that the USGS conducted its coal availability studies.
2. Using that methodology, improve estimates of the National Coal Reserve Base.
3. Determining the probable effects that clean air legislation and other environmental restrictions would have on coal production.
4. Developing baseline information to help with policy and legislative decisions affecting the competitiveness of coal mining in the United States and the State economies dependent on coal production.
5. Assisting Federal land managing agencies in the evaluation of coal resources on public lands.

ACKNOWLEDGMENTS

This report is the culmination of efforts by several State and Federal agencies working toward the common goal of determining the economically recoverable resources within a specific area of the central Appalachian coal region. The KGS and the USGS provided the geological modeling and data files from which resources were calculated. James C. Cobb, assistant State geologist (KGS), and his staff provided the detailed geological information, a tour of the Matewan quadrangle, and a review of the final report manuscript. M. Devereux Carter, Nancy K. Gardner, and Margaret F. Johnson (USGS, Reston, VA) contributed countless hours of training, resource calculations, computer guidance, and assistance in coordinating the USGS Coal Availability program with the Bureau Recoverability program. William G. Miller, manager of the USGS National Coal Resources Data System (NCRDS), Reston, VA, guided the Bureau acquisitions of hardware and software to provide compatibility with NCRDS. Carol L. Molnia and Vicky L. Clark (USGS, Denver, CO) provided computer assistance. Special thanks are extended to Anne M. Allen (mining engineer, Alaska Field Operations Center, USBM) for development of the many graphics used in this report.

The authors also thank the following technical editors in the coal industry for their critical reviews of the program methodology: Gregg R. Bierei and Peter Wyckoff, Arch Mineral Corporation; Jon E. Kelly, Kelly Engineering; and Robert H. Tuck, Tuck Engineering.

NEXT

[ Contents | Eastern Energy Home ]

Created by the EERT WWW Staff.