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By Charles N. Speltz

Coal resource data from public and private sources, in conjunction with previously published data, were used by the Bureau of Mines to determine the location and extent of strippable coal resources in Colorado. Total strippable resources of approximately 18 billion tons were estimated in 12 separate coal regions, fields, or deposits. Coal recoverable by contour mining techniques was not included. Criteria used in defining strippable resources were a minimum coalbed thickness of 2 feet and a maximum overburden thickness of 150 feet, except where the coalbeds are of exceptional thickness. Ail Colorado coal is either Cretaceous or Tertiary in age. Cretaceous coals occui In the Dakota Sandstone, the Mesaverde Group, and equivalent formations while Tertiary coals occur in the Dawson Arkose, the Fort Union and the Wasatch Formations, and equivalent formations. The strippable coal ranges in rank from bituminous in the Yampa region to ligniferous in the Denver basin. Ali this coal is low in sulfur content (less than 1 percent); ash content is low to high; heating value ranges from 3,000 to 12,000 Btu's per pound. Ash from the lignite of the Denver basin was found to contain an abnormally high percentage of kaolinite which conceivably could be recoverable as alumina.

Jan 1, 1976

By H. M. Coggin

The study summarizes the state of the art in rock mechanics, open pit and underground mining, leaching, geology, metallurgy and financial analysis Conceptual design of pit slope caving technique and analyses explore concepts for the exploitation of ore grade remnants in the walls and bottoms of open pit mines and the potential economics of the adaptations Several coded sites were examined for future studies where the feasibility of the method may be demonstrated. An extensive bibliography has been developed

Jan 1, 1977

The 53 countries that constituted Africa in 1992 accounted for a significant portion of total world output of a number of mineral commodities. However, the continent's total output for a number of major mineral commodities declined relative to the volume produced during 1991. (See tables 1 and 2.) The most conspicuous declines in mineral production from 1991 to 1992 were for cobalt and copper (declines of 28.6 % and 23.4 %, respectively), which could be partially attributed to mining and metal processing difficulties caused by political and economic disruptions in Zaire and for uranium (12 % drop), for which much of the continental production decline was ascribed to Namibian cutbacks in response to lower world prices. The severe regional drought also adversely affected the mineral industry in a number of sub-Saharan nations.

Jan 1, 1994

By Albert L. Toenges

ALMOST all of the coal used for metallurgical purposes west of the Continental Divide is ruined from the Lower Sunnyside bed in Carbon County, Utah. Coke produced from Lower Sunnyside coal and used in western steel plants is weaker structurally than coke used elsewhere in this country. For this reason, western coal operators and steel manufacturers are anxious to develop new areas of coking coal of better quality than the coal produced from the Sunnyside bed. Early in the war, the Bureau of Mines undertook an intensive investigation of western coals to (a) develop additional reserves of coking coal to supplement proved reserves in the Sunnyside bed and (b) develop, if possible, reserves of coal with coking qualities superior to Lower Sunnyside coal. Results of investigations in the Kemmerer district, Wyoming,9 and in the Minnesota Creek area, Gunnison County, Colo.,10 have been published.

Jan 1, 1952

By Robert J. Evans

The Bureau of Mines is sponsoring a variety of long-term, high-risk research to advance state-of-the-art technology in U.S. underground coal mining. This report reviews the status of many Bureau projects that support fundamental underground coal mining operations; the project areas include cutting coal from the solid (extraction), hauling coal from the face (transport), and activities that sustain daily operations (logistics). Innovative equipment and technology have been developed, with these major objectives: to significantly improve coal mine productivity, to further advance coal recovery and personal safety within the mining industry, and to reduce the time needed to develop longwall panels. The majority of the prototype equipment covered in this report either has undergone or will undergo comprehensive evaluation at Bureau surface test facilities so that performance and reliability can be improved before the equipment is tested and evaluated in a working section underground.

Jan 1, 1988

By WILLARD W. CUTLER

This bulletin reviews, in the light of recent experience, the use of production-decline curves in estimating the future production of oil from wells. It deals with the estimation of the reserves of recoverable oil in properties already producing or in those adjacent to them, takes cognizance of the physical laws governing expulsion of oil from oil sands, and shows how the production-decline curve can be made to utilize these laws in estimating reserves and rates of production. The valuation of oil properties should be based on the total amount of oil recoverable from a property by the methods in use, the rate of recovery, the cost of production, and the selling price. Numerous other curves besides those for reserves and rates of production may be formed from the production-decline curve and will present desired information in a convenient time-saving form. These curves also are described. Methods developed before the production-decline curve method was used are briefly discussed in order that the principles on which estimations of oil reserves are based may be made plain. The construction of curves and tables for estimating future production of individual wells and of average wells in most of the important oil districts of the United States is described and operating problems that may be solved by the use of production-decline curves are discussed. The bulletin does not deal with costs, oil prices, or the methods of evaluating oil properties. Many engineers have amply demonstrated the value of the production- decline curve method by forecasting within reasonable limits the production of many thousands of wells and tracts. The value of similar estimates depends however, on (1) the application of trustworthy methods; (2) the care and judgment of the estimator; and (3) the length and reliability of the records and the accuracy of ofher information used in estimating future production. When adequate records and information are available, experience has shown that It qualified engineer can forecast production far more accurately than has been deemed possible, except where the usual conditions governing the expulsion of oil from a sand have been radically changed by applying compressed air or by flooding with water, or, to a less degree, by using vacuum. In general, the production-decline curve method, though there are limits to its accuracy, is far more trustworthy than any other.

Jan 1, 1924

By S. H. Ash

NINE-TENTHS of the total anthracite deposits of North America are in Pennsylvania. Corrosion of pumping equipment by acid mine waters has been experienced at tremendous cost by mining companies in the anthracite region of Pennsylvania, for many years in many ways. The design and specifications of the large centrifugal pumps as provided in the proposed mine-drainage system (7-35, 45, 46, 48, 54, 64, 70, 71)° make it imperative that a metal or alloy be recommended that has the highest corrosion resistance and, at the same time, acceptable properties suitable for general workability (welding and machining). This report presents data on the corrosive and erosive effects of acid mine waters in the anthracite region on metals and alloys for pumping equipment and drainage facilities necessary to remove or control this water.

Jan 1, 1955

By William W. Adams

The quarrying and related industries of the United States improved their safety record in 1938 by reducing their accident-frequency rate to a lower acid more favorable position than it has occupied at any time except 1935 since comparable accident statistics became available in 1916. The rates for 1935 and 1938 were identical. The number of men employed in 1938, although smaller than in 1936 and 1937, was larger than in any other year since 1930. Volume of employment, as measured by the number of man-hours worked in the industry as a; whole, likewise was larger than in any year since 1930 except 1936 and 1937. Reports from operating companies to the Bureau of Mines, United States Department of the Interior, showed that 77,497 men were employed in 1938, a decrease of 6,597 compared with 1937. This figure represents the average number of employees for the period during which the quarries and plants were active during the year, which in 1938 averaged 223 workdays per employee compared with 241 in 1937. A total of 17.3 million man-days or 133.8 million man-hours of work was shown for the industry as a whole, which indicated a weighted average of 7.75 hours per man-shift. Reports for 1937 showed a total of 158.3 million man-hours for the entire industry and an average workday of 7.81 hours. Accidents resulted in the death of 82 employees, 5 more than in 1937, and in 5,027 nonfatal injuries involving disability for more than the remainder of the day on which the injuries were received. The number of nonfatal injuries was 1,321 less than in 1937. As the number of deaths and injuries was reduced more, proportionately, than man-hours of employment, the accident-frequency rate per million man-hours of work declined, the rate for 1938 being 38.19 compared with 40.59 for 1937. In other words, accident occurrence to the average employee was 6 percent more favorable in 1938 than in 1937 on the basis of actual number of accidents and actual number of man-hours worked during the 2 years.

Jan 1, 1940

By Frank A. Peters

With the current renewed interest in advancing the technology for producing alumina from domestic raw materials, revisions of previous cost estimates to provide planning data are urgently needed. Completely new cost estimates on a 1973 basis are included for four alumina-from-clay processes and one alumina-from-anorthosite process. These estimates are based on new or previously calculated material balances, recalculated heat requirements, and new equipment designs. The use of larger and more modern equipment has permitted a significant reduction in labor requirements as well as equipment costs. Chemical prices, labor rates, and utility rates typical of late 1973 are used in these cost estimates. In addition to the revised cost estimates, all 21 previously published alumina evaluations compiled by the Bureau of Mines were updated to show the effect of inflation using an inflation index and late 1973 chemical prices, labor rates, and utility rates.

Jan 1, 1974

By Robert S. Schechter

A minitest of the new potassium chloride-potassium carbonate two-stage in-situ uranium leach process has been carried out at the Intercontinental Energy Corporation (IEC) Zamzow project site in South Texas. Substantial quantities of high concentration uranium were produced indicating the viability of the leach solution. The test results yield information regarding the reservoir dispersivity, the average cation-exchange capacity of the formation, and the distribution coefficients describing cation-exchange reactions. The test also indicates permeability anisotropy and the existence of disturbed flow fields.

Jan 1, 1985

By William W. Odell

In Europe and in certain other foreign countries studies have been made, extending over a period of years, relating to the winning of oil from oil shale. More work has been done in these countries than in the United States, for the reason that a supply of natural petroleum has not been so generally available there as here. Information has been obtained relating to present practices in these foreign lands in the development of a shale-oil industry. It is realized that in the past there has been very little inducement to invest capital in shale-oil enterprise in the United State's because the supply of petroleum has been plentiful; however, the time possibly is not far distant when the utilization of oil shale may be cons¬idered a desirable and financially sound venture, as it may be necessary before long to augment our supply of oil with that recovered by processing shale. The data presented herein portrays at least some of the thoughts of those engaged in obtaining oil from oil, shale in Europe, and they depict some of the results thus far obtained as well as certain plans for further efforts to win oil from shale; it is hoped that those who undertake the development of a shale-treating industry in this country will find useful information in this report.

Jan 1, 1946

By S. M. Dar

The U.S. Bureau of Mines constructed a full-scale model of a 15-ft-wide coal mine entry to use in combination with finite-element analyses to investigate roof support systems and various types of roof bolts. The objective was to enhance understanding of the fundamental mechanics of the interaction between rock and supports and the relative integrity of bolted mine roof as a function of roof bolt type, length, spacing, and tension, and the basic characteristics of the roof strata. The laboratory test results, when correlated with computer simulations using fmite-element analysis and underground verification tests, should provide a basis for desigillng safer, more cost-effective roof control systems and help to establish guidelines for employing fully grouted resin and mechanically anchored bolting systems. The background for this research, the research approach, the methods and equipment employed, and the results are described in this report.

Jan 1, 1989

By W. W. Adams

With production of coal per man-hour of work at a higher level than ever before, the coal-mining industry of the United States established a near-record in lowering the accident rate of nonfatal injuries per million man-hours of exposure in 1940, the injury rate being lower, except for 1939, than in any year since 1930, the first year for which comparable figures for nonfatal accidents were collected by the. Bureau of Mines, United States Department of the Interior. The rate for fatal accidents, on the other hand, was not as low or favorable as in 1939, nor was it as low as in many years since 1910, the earliest year for which fatality rates were complete for all coal-mining States. Accident and employment reports received from mine operators and fatal-accident reports from State mining departments and inspectors showed that 533,267 men were employed at coal mules in 1940, exclusive of the number employed at coke ovens, Although this number represented 6,108 fewer employees than in 1939, a large increase was made in the volume of work performed and in the quan¬tity of coal produced. In 1940 the amount of labor performed at coal mines was 748 million man-hours, a gain of more than 10 percent over the previous year. The average employee worked 199 days, an increase of 20 workdays per man. Production of coal was nearly 513 million tons, an increase of 14 percent, of which more than 461 million tons was bituminous coal and more than 51 million tons was Pennsylvania anthracite. Accidents to mine workers caused the death of 1,388 employees; in addition, 59,781 employees were injured, and each injury resulted in disability of the employee for more than the remainder of the day on which the accident occurred.

Jan 1, 1942

By J. B. Gayle

Coke-pushing difficulties have been the subject of much controversy but relatively little scientific investigation. Nevertheless, continuing pushing difficulties can greatly decrease the life of a coke oven and should therefore be considered in the selection of the blend and operating conditions used for coke production. The present Federal Bureau of Mines investigation was undertaken to correlate results of previous investigators and to supplement these results to the limited extent practical by us of an experimental slot-type oven. To this end, pushing pressures have been determined routinely for Tuscaloosa oven tests conducted during the past 10 years. Nevertheless, the accumulated information remains incomplete in many respects, and in view of the recognized inadequacies of the data, publication is now undertaken only because of the scarcity of published information on this important problem and the discontinuation of carbonization studies with this oven.

Jan 1, 1961

By Sidney Katell

This report, covering the period January 1967 through December 1967, is a continuation of a series that began with the publication of Information Circular 7516 in October 1949. It is the ninth in a series of reports prepared in cooperation with the American Association of Cost Engineers. The abstracted articles are concerned with all phases of cost engineering in the field of chemical and petroleum plants and related subjects. They are from the following sources: 1. American Association of Cost Engineers Bulletin. 2. Bureau of Mines Information Circulars. 3. Bureau of Mines Reports of Investigations. 4. Chemical Engineering. 5. Chemical Engineering Progress. 6. Chemical Week.

Jan 1, 1968

A preliminary program dated April 25, 1974 was prepared for Development Engineering, Inc. (D.E.I.) on research and development, laboratory; field and other engineering studies for the disposal of retorted oil shale. This program was revised and published as a final document dated December 17, 1974. The document included a discussion on the peculiarity of retorted shale materials to be investigated and a discussion of the various laboratory and field tests which would need to be conducted to define their physical and chemical properties. The proposed research and development program was divided into eight work phases as follows: I - Program Development II - Exploratory Laboratory tests on old U.S.B.M., retored shale III - Laboratory tests on Pilot Plant retorted shale IV - Laboratory tests on retorted shale from Semi-Works Plant, and field and test plots and ponds. V - Field compaction tests

Jan 1, 1975

By Dana C. Reinke

Water well drillers are exposed to high levels of noise while working. NIOSH researchers have found that water well drillers are exposed to levels above 85dB (A) while performing certain tasks during a typical drilling job. Noise levels consistently over 85dB (A) during an 8–hour work shift are hazardous and can lead to hearing loss in workers. Finding ways to reduce noise exposure is difficult because of many factors. The work environment is constantly changing due to the location of jobs and environmental factors. The types of drill rigs required for drilling are expensive. Equipment can range from new to used (10 to 30+ years old). Drillers and owners can work together to prevent noise–induced hearing loss, and measures can be taken to reduce exposure to hazardous noise.[ ] Preventing hearing loss occurs through three stages. The first stage is removing noise from the source (i.e., drill rig). Various parts of a drill rig create noise besides the drilling rod. NIOSH researchers have examined noise levels of drill rigs. Some of the loudest parts of the drill rig include the compressor, engine, and cooling fan (Fig. 1). While removing the noise source from a worksite is ideal, the process would be expensive and difficult.[ ]

Jan 9, 2005

By Dana C. Reinke

Jan 1, 2005

By Gerald T. Homce

Data from the U.S. Bureau of Labor Statistics show that 89 water well drillers died on the job between 1992 and 2002, and 28 of these deaths were electrocutions (Figure 1). In fact, elec­trical accidents are the leading on-the-job killer of water well drillers. The use of electricity is such an integral part of our lives that we usually take it for granted, but if we don?t understand or choose to ignore the hazards associated with electricity, the results can be deadly. Why is electrical shock so dangerous? If the voltage (of a shock) is sufficient to drive electrical current through your body, just 10 milliamps of cur­rent (1000 milliamps = 1 amp) can cause muscles to contract and prevent you from releasing an energized wire or tool in your grip. As little as 30 milliamps of current can paralyze your breathing, and 75 milli­amps can cause your heart to stop pumping blood (ventricular fibrillation). As a comparison, a small bedroom night-light draws about 30 to 60 milliamps. Other factors influence how severely you?ll be shocked if you touch a live electrical circuit, such as the path electrical current takes through your body and how long it flows, as well as your body weight. How much voltage is needed to drive electrical cur­rent through your body? Not much! Generally, any power source at 50 volts AC or higher is considered dangerous.

Jan 1, 2008

By W. N. Hoskins

This report covers the final results of a two-phase contract study conducted between July 1974 and October 1976. A comprehensive summary of the initial phase of the study is included. Phase I of the study involved the investigation and evaluation of all potential candidate underground systems for mining the deeper deposits of oil shale and associated minerals in the Piceance Creek basin of northwestern Colorado. Phase II called for the refinement and the detailed technical and economic analysis of the most promising system, or systems, thus disclosed. Of the several systems initially investigated and evaluated, four showed considerable merit for exploiting the deeper deposits: (1) chamber and pillar mining with spent shale backfill, (2) sublevel stoping with spent shale backfill, (3) sublevel stoping with full subsidence, and (4) block caving mining using LHD's. Final refinement and analysis of these four systems indicated their technical feasibility over at least part of the range of conditions expected in the deeper deposits. Their economic feasibility also was indicated under certain operating and market conditions. A variety of engineering, production, and cost information is provided on each of these systems.

Jan 1, 1976