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By Theodore L. Turner

This Bureau of Mines report describes calcination of kaolinitic clay in a direct-fired 2-1/2- by 24-ft rotary kiln at 750° and 775° C. Methods for preparing kaolin feed materials and characterization of calcined products are discussed. Approximately 99 pct of the alumina in a typical eastern Georgia kaolin was soluble in HC1 after calcination at either 750° or 775° C.

Jan 1, 1982

By Loren R. Anderson

A probabilistic slope stability computer model was developed at Utah State University and independently evaluated by CH2M Hill Consulting Engineers as a design and analysis tool. Volume I of this report describes the model and Volumes III and IV are users manuals for the computer programs. This volume (Volume II) constitutes the report by the CH2M Hill. It includes a description of a field investigation and stability analysis of an existing tailings dam. Based on the results of the analysis, the tailings dam was evaluated for redesign using probabilistic considerations. Conclusions are made regarding the usefulness of the model as a design tool.

Jan 1, 1982

By G. R. Moulder

A device was developed that measures dynamic stress (ultrasonic energy) transfer through installed rock bolts, a measure that is directly proportional to the degree of grout bonding of the bolt to the mine roof structure and thus the ability of the bolt to bear static stress. The rock bolt bond tester (RBBT) is a hand-held portable device that shows three ranges of bolt bond condition; i.e., one-third (Bad bond), two-thirds (marginal), or fully bonded. These are shown respectively by a red, yellow, or green light that displays for 4 s. RBBT performance was verified with 2 1/2-to 8-ft bolts installed in various types 0f mine roof structures (sands tone, shale, and boney coal-mud), and 15 now being tested by the Bureau of Mines in mines across the United States. The unit is about the size of a five-battery flashlight and contains the transducer electronics, and battery pack. The RBBT is designed for extreme ease of operation, requiring only manual contact with the bolt and signal read-out. The batteries are rechargeable and the package is designed for durability in a mine environment.

Jan 1, 1983

By James C. Barker

The U. S. Bureau of Mines made a reconnaissance In the western Crazy Mountains for cobalt and associated metals as part of the Alaska-wide critical and strategic metals program. The area, located about 75 miles north of Fairbanks in central Alaska, is underlain by complexly faulted, predominantly clastic sedimentary rocks bordering the Tintina Fault system. Above background metal concentrations were found to occur in altered fault zones, tectonic breccias, soils, and ground water seeps and precipitates that either cut or are derived from the faulted clastic sedimentary rocks. Up to 0.115 pct cobalt and more than 2.0 pct zinc were detected in soil samples. Spring precipitates contained up to 1.3 pct zinc, 0.037 pct tungsten, and other metals. Some localities lacked cobalt but contained anomalous amounts of copper, lead, zinc, silver, and other metals. No outcropping of primary metallic minerals was located because of Colluvium and vegetation cover and extensive deep leaching. Therefore, whether the metal values encountered are due to primary deposits with economic development potential or are the results of concentration by ground water from low-grade sources is unknown. The presence of cobalt, nickel and zinc, and the identification of minor tin and tungsten indicate that further investigation is warranted.

Jan 1, 1983

Research by the National Institute for Occupational Safety and Health (NIOSH) on multiple-seam mining has resulted in two new ground control products. Information Circular (IC) 9495 In some U.S. coalfields, particularly in central Appalachia and the West, most mines are operating above and/or beneath previously mined seams. The effects of multiple-seam interactions can include roof falls, rib spalling, and floor heave. These can seriously threaten the safety of miners and disrupt mining operations. Information Circular (IC) 9495 is a proceedings document containing a variety of papers that summarize recent knowledge about multiple-seam mining. A NIOSH study that analyzed case histories collected from 44 U.S. coal mines is described in detail. The study confirmed that overmining is much more difficult than undermining, and isolated remnant pillars cause more problems than gob-solid boundaries. The study's results were the basis for the Analysis of Multiple-Seam Stability (AMSS) software package. The proceedings also contain two papers describing the LaModel family of software. The original three-dimensional version of LaModel is essential for detailed analyses of complex multiple-seam scenarios. LaM2D implements a simplified, two-dimensional model suitable for quick approximations of the multiple-seam stresses and strains. Three papers in the proceedings focus on case histories. One describes the extensive multiple-seam experience at the Harris No. 1 Mine in West Virginia, a second contains examples of "extreme" multiple-seam mining from the central Appalachian coalfields, and a third describes interactions with regard to longwall mine experiences in Pennsylvania, West Virginia, and Utah. The final paper reports on a numerical modeling study that provided some insight into the mechanics of multiple-seam mining. [ ] AMSS Software Package NIOSH has developed a simple, user-friendly computer program called Analysis of Multiple-Seam Stability (AMSS). AMSS can help mine planners to evaluate each potential multiple-seam interaction and take steps to reduce the risk of ground control failure. AMSS begins by evaluating the pillar design. It first calculates the single-seam pillar stability factor (SF)

Jan 11, 2007

By Sean Gallagher

Humankind's interest in measurement of human physical strength probably dates to the first humans. At that time, life was truly a struggle in which the fittest survived. To a great extent, fittest meant strongest. Interestingly, current interest in human physical strength in the workplace stems from 1970-1980s vintage research demonstrating that persons with adequate physical strength are less likely to be injured on physically demanding jobs. Survival in many modem workplaces may still be a case of survival of the strongest. There is, however, a flip side to this issue - that persons with limited strength are more likely to be injured on "hard" jobs. To address this problem, we can apply what we know about physical strength to job design. "Hard" jobs can be redesigned to be within the physical strength capability of most people. Since physical strength is important to these jobs, we must find ways to quantify it through testing. This publication concerns human physical strength testing. Its purpose is not to recommend any particular type of testing, but rather to describe the types of testing available and their uses. It is up to each individual user of strength testing to decide which testing technique is most appropriate for his or her particular application. This booklet discusses four types of strength testing: isometric, isoinertial, psychophysical, and isokinetic.

Jan 1, 1998

By Bing W. Jong

A bench-scale evaluation of coal and coal waste materials as aggregate materials for use in longwall mine supports was undertaken as part of the Bureau of Mines Health and Safety program on ground control. Performance data were obtained on portland cement concretes (PCC) prepared with coal and coal wastes as aggregate materials. The effects of high-early-strength accelerators on strength and creep and of superplasticizers on strength properties of PCC formulated with coal and coal waste were investigated. Concrete formulated with a high-early-strength accelerator and coal and coal waste has 20 and 40 pet greater compressive strength, respectively, than the control samples without admixture. A concrete formulated with coal waste and the high-early-strength accelerator, using four bags of cement per cubic yard and a water-cement ratio of 1.0, had the lowest creep value of all the coal- and coal-waste-formulated PCC's tested.

Jan 1, 1983

By Noel N. Moebs

The U.S. Bureau of Mines is conducting research on many topics relating to the mineral resources of the United States. This is done to ensure an adequate supply of minerals essential to a viable domestic industry and a sound economy. The United States is almost totally dependent on foreign supplies for a number of minerals such as chromium, niobium, tantalum, and manganese for which there is no available substitute, while many other minerals such as titanium are abundantly distributed throughout the earth but seldom occur in adequate concentrations or useful forms. This report describes an example of a small but high-grade occurrence of titanium are in Nelson County, VA. This occurrence could be exploited under favorable economic conditions with new mining technology such as borehole slurry mining. The report demonstrates that the dikes at titanium ore, a mixture of ilmenite and apatite locally termed nelsonite, can be detected and traced along strike using magnetometer traverses. This information will aid in the selection of appropriate slurry borehole mining test sites in the area.

Jan 1, 1993

By Walter W. Fisher

A study of copper cementation on iron was initiated to determine the effect that deposited copper has upon subsequent cementation. A microscopic investigation of cementation on an iron surface showed that cupric ion precipitates predominately on a growing copper deposit attached to the iron surface. A kinetic study of the cementation process in a revolving drum showed that the cementation rate is enhanced by the copper deposit attached to the iron surface and by the discrete copper particles of a cement copper slurry. The kinetic study also indicated that the character of the deposit is affected by the major anion in the solution. The cementation process is visualized to occur as a series of electrochemical cells in which cupric ion precipitates on copper dendrites attached to the iron surface.

Jan 1, 1973

By John F. Elliott

Six major trends that have had and are continuing to have major effects on the use and supplies of pig iron and scrap in the United States are (a) gradual replacement of the basic open hearth furnace (OH) by the basic oxygen furnace(BOF); (b) use of the electric furnaces for the production of plain-carbon steels, a trend which is closely related to the first; (c) United States changing from being a net exporter to a net importer of steel; (d) replacement of ingot casting by strand casting; (e) increased exportation of scrap; and (f) the lack of growth of the capacity of the U. S. steel industry to produce pig iron in the last 5 to 8 years. This report gives an analysis of the relationships between these trends and the use of processes for the production of raw steel in solidified form.

Jan 1, 1975

By R. N. Hambright

Gaseous and particulate exhaust emissions are characterized for a 1200 Bhp two-stroke cycle diesel, a 1000 Bhp four-stroke cycle pre-combustion chamber diesel, and a 900 Blip four-stroke cycle, direct injection diesel using steady-state modal testing and a versatile exhaust dilution-collection system. In addition, a 1.50 Bhp four-stroke cycle, pre-combustion chamber, turbocharged diesel was characterized for use in experimental water injection evaluations. Water injection downstream of the turbocharger compressor and upstream of the turbocharger exhaust turbine are evaluated for their particulate removal effectiveness on the small turbocharged diesel engine. The water droplets are inertially separated using cyclone separators designed for minimum pressure drop and outsize, lip to 50 percent of the total particulate mass generated was removed using a combination of both inlet and exhaust water injection techniques.

Jan 1, 1981

By P. M. Johnson

A design for a laser-powered optical interferometer, using a specimen whose thermal expansion is to be measured as part of the optical system, was conceived and applied in a prototype dilatometer. The object of thin work was the development of an absolute dilatometer capable of use at elevated temperature, particularly above 1,000° C. The prototype has been operated at temperatures exceeding 1,510° C. Results obtained with this device agree within 2.5 percent with the published data for the coefficient of expansion of columbium.

Jan 1, 1968

By Michael M. Hamilton

U.S. Bureau of Mines personnel examined mines, prospects, and mineralized areas to determine mineral resources and resource potential in and adjacent to the North fork Smith RARE II study area. Most mineral resources identified in this area are in laterites, highly-weathered residual soil zones. In the RARE II area, resources of nickel, cobalt, chromium, and magnesium were identified at 15 laterite properties and chromium resources at one chromite mine. Other commodities include copper, gold, silver, and mercury (fig. 1). Approximately 1,100 lode and 1,200 placer claims have been located in or adjacent to the area. Most placer claims are for literites. There are no patented claims or mineral leases. Forty laterite deposits on 15 ,properties within the RARE II area (fig. 2) contain about 16 million tons of identified marginal reserves and subeconomic resources containing nickel, cobalt, chromium, an magnesium (table 1). Most deposits have keen explored and are currently claimed. California Nickel Corporation is developing laterites on Gasguet Mountain, within and adjacent to the southeastern and western parts of the study area. If this project proceeds to production, a laterite processing plant on Gasquet Mountain would enhance the minability of other deposits in the study area. The Climax, PFM, DF, and Stone Corral properties (fig. 1, nos. 1, 6, 9, and 23) have deposits of sufficient tonnage and grade to attract mining interest; resources at these properties are in and adjacent to the RARE II area.

Jan 1, 1983

The Menominee Range of northern Michigan was a major producer of direct shipping iron ore for nearly a century. When the last underground mine on the Range ceased operation in 1978, it marked the end of an era. For since the start of mining in the early 1880's the district has gone through a Lull cycle from the start-up of mining through close-down. During this period over 200 million long tons of iron ore were produced and shipped from nearly 100 mining operations. This development and production spanned the time from when the United States advanced from an essentially rural-agriculatural society through the industrial revolution and into the beginnings of the computer and space age. There are many lessons that can be learned from such a rich history. This report attempts to provide ouch a lesson. Through the use of case histories, deficiencies in past mining practices and mine closure procedures that have resulted in current mine related problems are documented. These problems -an be grouped into three areas; 1) subsidence 2) hydrological or drainage problems and 3) problems related to inadequate mine shaft sealing and capping practices.

Jan 1, 1983

By Daniel G. Di Canio

Reference information and user instructions for Version 3.0 of the Accident Cost Indicator Model (ACIM) software package are presented. ACIM estimates the tangible costs of occupational injuries, illnesses, and fatalities in the United States mining industry.

Jan 1, 1983

By David D. Rabb

A report on location, sampling, assays, mineral examination, amenability leach tests, and evaluation of certain mine dumps in Mohave County, Arizona. Extractions of greater than 30 percent of the gold and silver were achieved during simulated heap leaching of selected mine dump material. Consumption of reagents was relatively low and results suggest leaching of prepared heaps is technically viable and could be economically attractive.

Jan 1, 1980

By R. V. Ramani, J. M. Mutmansky, P. C. Luna, V. A. Marple, Honglin He, B. A. Olson

The development of a sampling instrument for the assessment of an underground coal miner’s exposure to airborne respirable coal mine dust on a continuous and real-time basis has been long identified as essential for timely initiation of control actions. A respirable dust dosimeter (RDD) which operates on the principle of increasing pressure across a filter media with increasing dust mass on the filter has been developed by the National Institute for Occupational Safety and Health. Comparisons of the performance of the RDD with an U.S. approved gravimetric respirable dust sampler (GRD) have shown that the RDD may meet the requirements for measuring miners’ exposures on a cumulative, near real-time basis such as mid-shift and end of shift exposures. Recently, the performances of the RDD and GRD were compared by conducting side-by-side area sampling experiments in a controlled experimental environment in the laboratory and in underground coal mines under normal operating conditions. In this paper, the results from the in-mine study are presented and discussed. The experimental design for the in-mine study included two mines in different coal seams in different geographic coal regions. To ensure a wide range of concentrations, the experiments were conducted in a continuous miner section in Mine 1, and a longwall face in Mine 2. Airborne dust sampling was conducted for four different shifts at each mine. In each shift, two samples of different exposure durations were collected from two different locations. Each sample consisted of the readings of three dosimeters and the exposed filters from the three paired GRD samplers. As a result, a total of 96 comparative samples were obtained, 48 for each mine. The data were analyzed for the precision of the RDD and GRD measurements and for the relationships between the differential pressure of the RDD and the mass of dust on the paired GRD filter. The analyses indicate that, on the average, the RDD and the GRD track the airborne respirable dust concentrations well, exhibiting both a high correlation between the two measurements and a reliable predictive relationship of one from the other. Details of the experimental design, data analyses procedures, results, conclusions and recommendations of the underground experiments are presented in this paper.

By Loren R. Anderson

Traditionally, an evaluation of the safety of slopes has been based on computing a safety factor against failure. In computing the safety factor, the geometry of the slope, the soil parameters and the pore pressures are treated as deterministic quantities even though they are known to be random variables. A pseudo-three-dimensional probabilistic slope stability model has been developed that treats shear strength as a random variable. The model uses the probability of a slope failure as an assessment of slope reliability. The model can accommodate zoned embankments of soil in which the strength is described by the Mohr-Coulomb strength envelope. Autocorrelation functions are used to describe the spatial correlation of the strength parameters, c and tan ø. Model error can also be included in the analysis. The model has been applied to an existing tailings dam and to several hypothetical examples. These examples are presented to illustrate the influence of the choice of the soil strength variability parameters on the probability of failure. The results show that the critical failure surface based on the minimum safety factor is not necessarily the failure surface that will yield the maximum probability of failure. The analysis of the tailings dam shows that variance reduction can be large and that the model error is the dominant source of uncertainty for the embankment analyzed.

Jan 1, 1982

"INTRODUCTION Industrial utilization of the present submarginal domestic manganese resources of the United States is wholely dependent at this time on the electrolytic manganese process established as the result of 4 years of continuous operation of the Bureau of Mines pilot plant at Boulder City and 7 years' operations of the Electro Manganese Corporation commercial plant at Knoxville, Tenn.Three Kids ore provided the feed for the Boulder City pilot plant during 3 years of operation. Hence, the electrowinning characteristics of the ore have been thoroughly established, making possible accurate estimates for commercial operations.Before the Defense Plant Corporation constructed the leaching plant, the Bureau of Mines conducted an exploration project to determine the extent and grade of the ore reserves. Additional exploration, development, and mining by the Manganese Ore Cc, have accurately determined the tonnage and grade of ore. A large tonnage of stock piled ore is now available for immediate processing, and a considerable tonnage of openpit ore has been stripped of overburden preparatory to mining. Numerous facilities, such as power, water, and housing, needed for an electrolytic manganese plant are already available.All of these factors, as well as plans for installation of scale electrolytic manganese plant facilities, are presented in detail in the chapter entitled, ""Mining and. Electrolytic Reduction of use from Three Kids Manganese Mine."" The Manganese Ore Co. kindly provided information on the present ore reserves and state of development of the mine."

Jun 1, 1945

By G. F. Kuncir

The time-cost-risk analysis described herein was performed as part of an evaluation of the Advancing Oil Shale Mining Technology Program performed by The Aerospace Corporation. The objectives of this analysis are to assess the feasibility of the program relative' to time and cost constraints, and to determine the probabilities of achieving various technological goals. A combination of standard program planning and analysis techniques were used to achieve these objectives. These included a critical path analysis, a resource allocation analysis, and a risk analysis.

Jan 1, 1977