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By Noel N. Moebs

Valley Camp No. 3 mine was the scene of an experimental shortwall introduced in 1973 in an attempt to improve the recovery from the Pittsburgh coalbed in the Ohio Valley area where adverse ground conditions have imposed partial extraction methods with only 40 to 55 percent recovery of the valuable resource. The Bureau of Mines, under a cooperative agreement with Valley Camp Coal Co., monitored ground pressures and caving in the shortwall section in an effort to determine whether the roof strata, notably the limestone main roof, will cave to the extent that roof pressures at the face are relieved and whether the powered roof supports can sustain the roof load. The Bureau's efforts included mapping of clay veins, instrumentation of chain pillars and shortwall panels with encapsulated pressure cells, recording hydraulic pressures in the legs of the shortwall chocks, and core drilling underground and from the :surface. The experimental shortwall was a qualified success. Recovery increased 5.4 percent compared with partial extraction. Pressures in chain pillars and the abutment zone were not excessive. Hydraulic pressures in the chock legs did not approach the yielding pressure. Apparently, the limestone strata caved and the roof pressure at the face was relieved.

Jan 1, 1976

The objective of this study was two-fold: 1. To perform a world literature search pertinent to the analysis, selection and design of hoisting systems and their components and to codify the search into a literature compendium. The search resulted in a technical data file of over 1500 hard copy items. The compendium index was also suitable for establishing a comprehensive computer-loaded data base on the subject. 2. To develop a comprehensive system of guidelines to cover salient aspects of analysis, selection and design of electrical, mechanical and structural components of a hoisting system with a view to establish parameters for maximum safety and efficiency of operation, installation and revision of the system. 3. Major mechanical components in the hoist and mechanical drive train are considered. Design and specification criteria based on American standards and practices are developed as they apply to typical mine hoist arrangements.

Jan 1, 1988

By Michael J. Beus, Stephen Iverson

BACKGROUND A mine shaft is the lifeline to underground mines. Mine operators depend on safe, uninterrupted, and efficient movement of workers and materials. The shaft and hoisting system provides access to the network of openings used to recover the underground resource, provides vertical transport of miners and materials, and serves as an escapeway in case of an emergency. Accidents involving hoisting can be catastrophic. Such was the case in 1973 at the Markham Colliery in Derbyshire, UK when the conveyance overwound and fell to the shaft bottom, resulting in 17 deaths. Hoist and elevator machinery must meet the requirements specified in the Code of Federal Regulations (CFR), Parts 57 and 75. According to the Mine Safety and Health Administration (MSHA) data, many shaft-related accidents in the United States are associated with the hoisting cycle. MSHA statistics show that there were about 1500 shaft- related accidents in the 5-year period between 1992-1996. Most of these accidents resulted from the action, motion, or failure of the hoisting equipment or mechanism and involved movement of the conveyance which includes cages, skips, ore buckets, and elevators. A hoisting hazard may be characterized as an "unsafe hoist operating condition caused by insufficient or inaccurate information available to the hoist operator" (authors' quote). Earlier investigators have defined safety features and operating and maintenance standards for hoists, and reported on monitoring and control systems and sensors for hoists and conveyances [Farley, 1983; Ward, 19931. However, despite the considerable technological progress and hoisting control improvements in recent years, safety- related issues that require further investigation still remain. The hoist operator must constantly be aware of two important hoist-operating conditions: the position of the conveyance and the tension in the hoist rope. If this information is not available or is inaccurate, the hoist becomes unsafe. Current technology provides this information indirectly from sensors and indicators in the hoist room. However, unlike a building elevator hoistway, mine shaft hoistway problems often include: 1. poor ground conditions and excessive shaft wall and guide displacement; 2. rock bursts in deep mines (resulting in large rock movements and fragments blocking the hoist way); 3. water, ice, and salt buildup (impeding the smooth flow of the conveyance); 4. severe vibration from hoisting (resulting in loose guide support brackets, broken welds, or other alignment and conveyance mechanism malfunctions). The second issue relates to dynamic rope loads applied during normal winding, particularly during loading, acceleration, and stopping. Safety factors on wire rope are based on static load. They are artificially high to account for all cases of dynamic loads, even though the total load history on the rope (static and dynamic) during service is unknown. Therefore the tension, and thus the compliance with wire rope load safety factors, is unknown to the hoistman.

By Kim B. Shedd

An initial evaluation of the flow of cobalt-containing materials in the United States was prepared. The following aspects of materials flow were included: cobalt released as a result of mining and processing other metals and minerals; scrap generation and subsequent recycling or cobalt recovery; and cobalt losses resulting from the generation of wastes, dissipative uses, and disposal of used products. Where possible, estimates were made to quantify the amount of cobalt lost from the materials flow. More than 2,000 metric tons (mt) of cobalt are released annually from mining and mineral processing in the United States, including 480 mt of cobalt in coal produced in the United States. Metallurgical industries examined in this study have well-established recycling or cobalt recovery practices. The petroleum industry recycles spent catalysts, and some chemical catalysts are also recycled. Losses generated during cobalt chemical and powder processing were estimated at 50 to 80 mt of cobalt annually. Losses from alloy processing and the manufacture of parts and products were estimated to be 360 mt. These industrial losses are greatly outweighed by an estimated 2,780 mt of cobalt' consumed in the United States each year to make products that will ultimately be disposed of.

Jan 1, 1992

By C. W. Owings

One phase of Bureau of Mines health and safety work is promotion of the use of safe and effective dust-collecting devices in connection with rock drilling in coal mines. To insure that adequate equipment of this type is available to the coal-mining industry, the Bureau of Mines conducts investigations and issues approvals for dust-collecting equipment that meets the requirements of a schedule established for testing dust collectors intended for use in connection with roof drilling for roof bolting and for other rock drilling. 6/ Performance tests are conducted under the provisions of this schedule by engineers of the Branch of Health Research. This circular describes briefly the requirements and procedure for approval and lists drill-dust collectors that have been granted approval as of January 31, 1956. The addresses of manufacturers of approved devices are listed alphabetically at the end of this circular.

Jan 1, 1956

By L. Douglas Smoot

This research program was a theoretical and experimental study to improve understanding of the mechanisms of flame extinguishment in methane-coal dust-air-suppressant mixtures. This final report is a summary of work conducted during this grant, sponsored by the Bureau of Mines. Work under this new grant closely followed a recently completed contract for the Bureau of Mines that was conducted at this laboratory, and results of the earlier contract are also summarized in this report, as required in the grant work statement. The experimental effort was concentrated on supplementing the limited data available to describe laminar flames in methane-coal-air-suppressant mixtures. The theoretical effort was devoted to developing a comprehensive model that could be used to explain and extrapolate the experimental data. Selected for study were the following flames: Methane-air; methane-air plus KHCO , KNO3, K C204, KBr, Al203 or Monnex; methane-coal dust-air; coal dust-air with size, volatiles content, and concentration as variables, and coal dust-air plus KHCO3, KN03, KBr, NaCl or CaC03.

Jan 1, 1978

By Alla D. Mah

THERMODYNAMIC data for manganese and its inorganic compounds have not been critically surveyed since the work of Maier (31) 3 in 1934. At that time data were lacking or inadequate for many of the important metallurgical compounds. Experimental work, conducted during the intervening years, has supplied so many new thermodynamic values that it is again desirable to examine the available data and compile them into a single publication for handy reference. This paper consists of three main sections. The first summarizes the basic metallurgical thermodynamic data for manganese and its compounds, including heat capacities, entropies, heat contents, temperatures and heats of phase changes, vapor pressures, and heats and free energies of formation. All data available to May 1959 have been considered. The second section contains heats, free energies, equilibrium pressures, and equilibrium constants of reactions of manganese compounds, with special emphasis on metallurgical reactions. The third section supplies basic thermodynamic data for other elements and compounds encountered in metallurgical reactions of manganese, thus making it possible for the reader to conduct thermodynamic calculations without recourse to other literature.

Jan 1, 1960

By Mark I. Copeland

A study was conducted to determine if commonly used alloying additions or coating materials can prevent the formation of a liquid-copper phase during the reheating of copper-containing steels. If so, the tendency of such steels to surface-crack during hot-working might be eliminated. Steel specimens were scaled by heating them either isothermally or in a programed manner that simulated industrial furnace practice. Metallographic examination of the heated specimens showed that molten fayalite (Fe2Si04) completely prevented the formation of liquid copper at the surface. Fayalite, which melts at 2,200° F (1,205° C), was formed by internal oxidation of the silicon contained in the steel. By forming complex molten oxides, coatings of borax glass were also effective in preventing the occurrence of liquid copper at the steel surface.

Jan 1, 1972

By G. A. Wancheck

Shear tests were performed on several prepared samples of granular and powdery bulk materials to investigate the following parameters: Particle size and distribution, particle movement, moisture content, consolidation of material, bulk density, void ratio, porosity, volume change, and strain rate. A series of shear tests was performed with weight-percent-ratios of minus 0.185-inch tertiary sand and 1-1/2-by l/2-inch tertiary gravel mixtures, and weight-percent-ratios of minus 200-mesh limestone (rock dust) and minus 200-mesh bituminous float coal dust. A comparison was made for shear test results obtained with rectangular and circular shear cells utilizing the large and small direct shear testers. Specifically, the shear results obtained include the angle of internal friction or shear strength of the tested material under known consolidating pressures, and the kinematic angle of friction or coefficient of friction between the interface of a bulk material and a sample wall material. The experimental procedure, tests, and results are given for each parameter investigated.

Jan 1, 1973

By J. W. Howland

A demonstration of dozer blades, designed for recontouring area-mined spoil and shown effective at Kansas and East Texas surface mine sites, was conducted at a Northeast Arizona surface coal mine to determine their effectiveness in different climate and soil conditions. The specialized tools were: 48-ft angle blade (on side-by-side tractor), 24-ft grading bar, modified 24-ft "U" blade (on side-by-side tractor), and a 13-ft deep "U" blade. Interest in the increased dirt-handling capacity of a previously built 22-ft blade, resulted in the design of a new Centerflow Blade of good versatility, able to maintain increased flow in otherwise difficult-to-move spoil. The demonstration involved 263 acres and showed a reduction of 50% in reclamation costs and 20% in fuel requirements for this mine site over conventional equipment. This savings resulted from improved technology, trained operators, and rigorous application of supervisory and monitoring techniques. Procedures and results of the demonstration are presented and analyzed here, along with guidelines for application of findings.

Jan 1, 1982

By Robert W. Waytulonis

This publication contains 1,000 citations of technical and semi-technical literature treating diesel-powered equipment usage underground both generally and specifically. These citations were gathered by U.S. Bureau of Mines personnel over the period of 1978-1983. The citations concern diesel engines as powerplants for underground mining use; their design, emission characteristics and control, maintenance, usage; and health and safety aspects. All citations have been abstracted and arranged 1n a subject classification system with extensive cross-referencing.

Jan 1, 1983

By Terry J. Close

A mineral resource survey of the 940-square-mile (2,434 km2) Hells Canyon study area, which includes Hells Canyon Wilderness, Snake and Rapid Wild and Scenic River's, and adjoining roadless lands in Oregon and Idaho, indicates the area is highly mineralized. Thirty-four lode deposits within the study area have resources totaling about 31 million tons (28 million t) containing copper, silver, zinc, gold, and lead; another 42 lodes, not sufficiently exposed to allow resource estimates, are believed to have mineral potential. The most important deposits are copper-, silver-, zinc-, gold-, and lead-bearing volcanogenic occurrences, followed by silver-and copper-bearing contact replacement (tactite) deposits; other lode occurrences are relatively unimportant. The most important placer deposits occur at Dry Diggins; placers along the Snake River are small and scattered. The study area has extensive deposits of limestone and sand and gravel; it has little potential for energy resources.

Jan 1, 1982

By Mark S. Redfern, Kim M. Corneliusa, Christopher A. Hamrick, Sean Gallaghera

Coal miners often handle heavy electrical power cables, weighing up to 10 kg per meter. These cables are manually lifted and attached to the mine roof to prevent damage from mobile underground equipment. Data suggest that workers who commonly perform cable handling tasks experience a high rate of lost time back injuries. In this study, six male underground miners performed a total of 12 cable-hanging tasks in standing, stooping, and kneeling postures, during which kinematic and ground reaction force data were collected. Reductions in vertical work space were found to result in a linear increase in the peak moment experienced by the lumbarspine (p<0.05). In restricted postures, peak moments were not significantly different in stooping vs. kneeling postures (p>0.05). Average lumbopelvic flexion during the tasks was highest in stooping conditions, followed by standing and kneeling exertions (p<0.05). Implications of this data with respect to design of cable handling tasks are presented and discussed. Keywords: Biomechanics, posture, low back pain, restricted workspace, mining

By Kevin Connor

There was little change during 1988 in the production of minerals in Burundi. The Government of Burundi, which banned all commercial mining operations in the country in 1979, lifted the ban on mining of alluvial gold deposits and started a program of small-scale artisan gold mining in October. Along with the legal mining of gold, licensed gold trading counters were established. Other mineral commodities produced were kaolin clay, lime, and peat. In compliance with the Government ban, the only mineral wealth exploited for commercial sale and export was alluvial gold. Through financial assistance from the International Bank for Reconstruction and Development (World Bank) and the United Nations Development Program (UNDP), a study to inventory the country&apos;s mineral resources continued throughout the year. As part of this study, during the year, a West German company undertook a drilling program to further outline the nickel reserves of the Musongati area in central Burundi. Results of the work as of yearend were disappointing, with only 12 million tons of ore identified with better than 2% nickel content proven. Investigations also continued during the year regarding the centrally located deposits of vanadium-bearing titaniferous magnetite. A Norwegian company contracted to prepare a prefeasibility study for developing the deposit. The British Sulphur Corp. Ltd. was nearing completion of its $1.2 million2 study of the phosphatic limestone deposit at Matongo-Bandaga at yearend. Ore reserves of about 17 million tons grading 11% phosphorus pentoxide (P2O3) had been identified. The phosphate zone overlies a carbonatite rock, which could provide the basis for a cement industry. Additional drilling was planned for 1984. Exploration for gold was underway in 19S3 in northern Burundi through UNDP funding. Several primary deposits of shallow semimassive sulfides with gold values ranging from traces to 11 grams per ton had been discovered. With assistance from the Federal Republic of Germany, bastnasite reserves of 5,400 tons, with associated high europium oxide and cerium content, were verified, and the prospects for finding

Jan 1, 1985

By M. E. Volin

The Smuggler is one of the mines in the Aspen district, located the central part of Pitkin County, Colo. It was first examined in July 1943 by C. R. Wilfloy, former mining engineer of the Bureau of Mines at Salt Lake City, Utah, in, company with the lessees, R. D. Rohlfing of Aspen and J. W. Vanderwilt of Denver. The purpose of this examination was to sample a mineralized breccia zone that appeared continuous along the contact between the Leadville and Weber formations. These preliminary samples showed that the zone contains low but significant amounts of lead and zinc and that the minerals are partly oxidized and thus not easily concentrated. The mine was examined again in May 1946 by the senior author and William Herron, one of the present lessees of the property. This examination reviewed the previous sampling and recommended investigations by the Bureau of Mines. Sampling and drilling investigations were conducted by the Bureau from October 1946 to February 1947 and again from August 1947 to April 1948. Aspen is the center of a famous mining district that produced over $102,000,000 in silver and lead ores from 1880 to 1918, when a dispute closed down the mines (fig. 1). All of the workings below the Cowenhoven tunnel in Smuggler Mountain and the lower Durant tunnel in Aspen Mountain have been flooded since that time. The Cowenhoven portal now is caved, and Smuggler Nos. 1 and 2 tunnels are the only accessible workings in Smuggler Mountain. The only operating mine is the Midnight, situated 4 miles south of town at an altitude of 9,700 feet.

Jan 1, 1950

By Robert L. de Beauchamp

The Bureau of Mines designed a chlorination apparatus to prepare CrCl2 free of CrCl3 by the direct reaction of chlorine and chromium. Equipment and procedures were developed for routine preparation of 25-pound batch quantities of anhydrous CrCl2. Calcium, iron, nickel, and silicon impurities were in the 0.01 to 0.05 percent range, and all other impurities were below 0.01 percent.

Jan 1, 1968

By F. N. Kissell

The machine-mounted continuous respirable dust monitor (MMCRDM) is a fixed-location area sampling device developed for possible use at the working face of an underground coal mine. This device, based on proprietary technology known as the tapered element oscillating microbalance, has evolved over the past eight years through a cooperative effort of the former Bureau of Mines, MSHA, and the Rupprecht & Patashnick Company in Albany, NY. The capability to measure respirable coal mine dust levels on a continuous basis, rather than depending solely on periodic samples obtained from the traditional coal mine dust samplers, has been a goal in the mining industry for nearly two decades. Recently, an extensive series of laboratory and underground tests was conducted by NIOSH with the cooperation of MSHA and coal operators to test the performance of the MMCRDM In preliminary laboratory testing, the MMCRDM seemed to work well. However, in every underground test, when compared to reference samplers placed close to the inlet, the MMCRDM failed to meet the 25% accuracy criterion specified in the contract under which it was developed. Two reasons explain this failure: First, in most tests the bias (the relative discrepancy between the average MMCRDM concentration and the average reference sampler concentration) was too great. Second, the variability of the samplers used for reference comparison was too large. Finally, the underground testing of the MMCRDMs showed that they are quite unreliable at this stage of development. In the majority of mine tests, no more than 10 shifts of data were taken before the MMCRDM failed to function properly. Major breakdowns, requiring the return of the MMCRDM to the factory for repairs, occurred on average every 28 days. To be considered mine-worthy, MMCRDM reliability must be substantially improved. KEYWORDS Dust, coal dust, dust instrumentation, dust sampling, dust monitoring, black lung, pneumoconiosis

By J. L. Howell, D. E. Pollock, A. B. Cecala, A. D. O’Brien

Dust from worker,s clothes has been shown to be a problematic source of personal dust exposure. A recently completed effort between NIOSH and the Unimin Corporation has resulted in a quick and effective way to clean worker clothing. The process involves a booth under negative pressure with an air spray manifold to supply compressed air to blow off the dust from the clothing. The overall system is designed to meet MSHA and OSHA requirements. Results of field testing indicated that the manifold cleaned the clothes 10 times faster and removed 50% more dust than cleaning methods used by workers today.

By H. V. Makar

Laboratory tests were performed to obtain a quantitative description of the effectiveness of sodium sulfate (Na2SO4) for removing copper from molten iron and to determine the effectiveness of Na2SO4 on actual auto scrap. The tests were conducted on induction melted heats of iron averaging 0.58 and 1.50 percent initial copper and on cupola-melted auto scrap containing 0.45 percent initial copper. The Na2SO4 was added in powder form in amounts ranging from 2.9 to 43.8 percent of the weight of iron being treated. The data showed that copper removal for the various Na2SO4 treatments followed a similar trend, regardless of the iron composition that was tested. The equation Y = 1 - e-3.23x approximately reflects the relationship between copper removal and amount of Na2SO4 added, where Y is the fraction of copper removed and x is the ratio of the weight of Na2SO4 added to the weight of metal treated. Copper removals ranged from 3.3 to 74.5 percent and reductions down to less than 0.10 percent final copper were achieved in the auto scrap. Copper removals were generally accompanied by sulfur removal, and initial sulfur contents ranging from 0.10 to 0.20 percent were reduced to as low as 0.02 percent. High temperatures and long slag reaction times tended to induce copper and sulfur reversion from the slag, but, generally, the Na2SO4 treat¬ments were effective up to approximately 2,820° F with reaction times not exceeding 7 minutes.

Jan 1, 1968

By J. J. Forbes

This publication is a revision of the first of a series of four Miners&apos; Circulars originally prepared and issued in 19&apos;29 for use in a course of training designed to prepare mine officials to organize men for rescue and recovery operations. These circulars were revised in 1937 and 1938 and again in 1948. This circular (Miners&apos; Circular 33) discusses mine gases and methods for detecting them. The second of this series (Miners&apos; Circular 34) gives instruction in Bureau of Mines methods of sampling and analysis of mine gases; the third (Miners&apos; Circular 35) describes methods and equipment used for protection against mine gases; and the fourth (Miners&apos; Circular 36) explains procedures used in sealing and unsealing mine fires and in recovery operations after mine fires or mine explosions.

Jan 1, 1954