Mines and Mineral Resources

Subsidence Resulting From Multiple-Seam Longwall Mining in the Western United States - A Characterization Study

United States Department of the Interior, Bureau of Mines — Wed, 24 Aug 2011 15:26:52 PDT

This report details the investigation of multiple-seam longwall subsidence conducted by the U.S. Bureau of Mines from 1978 to 1989. A field investigation monitored ground surface movements over four upper-seam longwall panels and six lower-seam panels. The characteristics of the subsidence occurring as a result of mining these panels are examined; in particular, the angle of draw, subsidence development, total magnitude and areal extent, and critical width are evaluated and discussed. Comparisons are also made between the characteristics of multiple-seam longwall subsidence and single-seam longwall subsidence that occurred at the same site.

Surface Subsidence Over a Room-and-Pillar Mine in the Western United States

United States Department of the Interior, Bureau of Mines — Wed, 24 Aug 2011 14:47:41 PDT

This report summarizes the results from the subsidence research study completed by the U.S. Bureau of Mines at the Roadside Mine, Powderhorn Coal Co., Palisade, CO. This research was conducted from February 1981 to August 1985, with additional data obtained during July 1991, to evaluate residual subsidence. The Bureau studied subsidence at three distinct room-and-pillar sections at separate locations over the mine and determined the maximum subsidence values and surface subsidence profiles for each mining section. Maximum subsidence of 3.0 ft. occurred over the room-and-pillar sections, with over-burden depths ranging from 50 to 600 ft. Surface tension cracks had occurred, and were still evident during the residual subsidence survey.

Hydrocarbons and Mineral Resources of the Uinta Basin, Utah and Colorado

United States Department of the Interior, Indian Affairs Bureau — Tue, 10 May 2011 13:58:39 PDT

The Uinta Basin holds special fascination for economic geologists because of its rich and diverse assemblage of mineral and hydrocarbon resources. Due to their presence in rocks of the basin, much effort has been put into assessing and exploiting uranium, phosphate, gold, copper, coal, and evaporite minerals. However, the basin is probably best noted for its extensive and very rich accumulations of hydrocarbons such as, oil, gas, bituminous sandstones, oil shale (shale oil), and gilsonite and other solid and semi-solid hydrocarbon species. More importantly, several of these commodities have proven to be a major source of wealth and resources for both local communities and the nation. The Uinta Basin is now playing an additional very important role as a natural-Earth laboratory where industry, government, and academic scientists can study the origin and habitat of these commodities set in a variety of rock types. Also, scientists can test methods for exploitation in an economically successful and environmentally sound manner. In addition, the basin is a training site for petroleum geologists from many countries who visit its exposures and study its resources as part of many industry, professional society, and academic field trips. Infomation and experience gained from studies are being applied to exploration and exploitation locally, as well as in a wide variety of places around the world.

Measuring Species Diversity on Revegetated Surface Mines: An Evaluation of Techniques

United States Department of Agriculture, Forest Service — Fri, 15 Oct 2010 13:18:46 PDT

This report reviews the three most commonly used techniques for measuring species diversity in plant communities: (1) diversity indices, (2) rank correlation tests, and (3) similarity indices. The author discusses the suitability of each technique for assessing species diversity on mined land and evaluates the most often used indices, test statistics, or coefficients of each technique. Applications of the Shannon-Weiner diversity index, Spearman's rank order correlation coefficient, Motyka and others' and Bray and Curtis' version of Sorensen's similarity index, and Spatz' version of Jaccard's index for assessing mined land species diversity are presented in the appendix.