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By Ronald C. W. Webber‑Youngman, Philani Larrance Ngwenyama

Entrapments are a huge risk in underground mines. This happens when miners (or any other persons who have entered underground) survive the initial event of an accident, become trapped or lost in unknown and life-threatening locations after evacuation, and remain unaccounted for. At this point, every second counts, and emergency response is highly desired for any chances of saving survivors. The survival chances of the missing persons depend on how quickly they can be located. Rescue teams are often deployed to search for the missing persons underground. However, the rescue teams are forced to search in random and presumed areas of the mine. This is due to the unavailability of information pertaining to the whereabouts of the missing persons. Not only the provision of accurate locations, but various other types of information such as post-accident two-way communication can enhance the survival chances of the missing persons. This information can be provided by a fit-for-purpose missing person locator system. A wide variety of missing person locator systems are already commercially available, some are in testing phases and others in prototype and development phases. This includes tracking, tracing, location detectors and post-accident two-way communication systems. These systems have unique functionalities, capabilities and limitations; making it difficult for mines to select the most effective, applicable and suitable system specific to their mine. In this study, the user requirements for a fit-for-purpose missing person locator system were developed. The purpose of the user requirements was to provide a guideline to facilitate the system selection process. The user requirements can also be used as a tool to measure and evaluate the performance of the selected missing person locator system. The user requirements were also used to predict the success of the selected system under different missing person incident scenarios. The development of the user requirements showed a potential for many other benefits for missing person locator systems.

Nov 2, 2023

By Thomas C. Poulter

Abstract The Poulter seismic method of geophysical exploration is an attempt to obtain an increased efficiency in the conversion of the energy of an m~pl06ion into useful energy which has directive properties and which contains a minimum of random frequency and random phase relations. Very little effort has been made in the past to simplify OT even control the uniformity of the seismic energy being introduced into the ground. The Poulter seismic method is also an attempt to improve the signal-to-noise ratio not merely by trying to complete the impartial filtering done by the earth on ,the continuous spectrum of primarily high-frequency energy radiated from a shot point but by applying a frequency control at the point of origin of the seismic wave. The energy from a shot-hole charge is peaked in a frequency which is much higher than will be transmitted through the ground, and its absorption introduces background interference. Only 10 to 20 per cent of the seismic energy of a shot-hole charge .is directed downward in a 90-degree vertical cone, whereas, from a pattern of charges detonated above the surface of the ground, 85 per cent of the seismic energy is included in a 90-degree cone and in some cases it is even confined to as small as a 30-degree cone. This greatly reduces the horizontally distributed energy, thereby producing a marked improvement in the signal-to-noise ratio. The frequency of the signal energy may be peaked in a rather narrow range by the proper application of two or more impulses upon the surface of the ground controlled as to direction, magnitude, and timing. These impulses may be controlled by the reflection shock wave technique, the pressure pulse technique, and the sequence firing technique, using the primary controls as outlined. The information obtained from the study of directivity of seismic energy in a high velocity, uniform material such as the ice on Taku glacier, in the Juneau ice field in Alaska, has been of great assistance in the application of the method to oilfield and mining problems.

Jan 1, 1950

By Xuexin Ding, Weijie Wei, Jinwang Zhang, Yi Chen, Shengli Yang

"Many ultra-thick coal seams exist in Xinjiang and the northern part of the Inner Mongolia. These coal seams are more than 30-40m thick. This kind of the thick coal seam is too difficult to extract in one slice, so the top-coal caving longwall mining method was designed for this purpose. In order to study the movement characteristics of the overburden strata and the development of the ""three zones"" in ultra-thick coal seams, the physical and numerical simulations were carried out based on the in-site condition of Baiyinhua coal mine. The result shows that, when extracting the upper part of the l 5m thick coal seams, the first weighting interval was 50-58m and the periodic weighting interval was I 8-20m. The caving zone, fractured zone and bending and sinking zone were 38m, 92m, and 50m respectively in height. The fractured zone height increased with the advancing distance of the face, but in some localities, a ladder-like distribution due to the periodic weighting existed. When extracting the lower part of the 25m thick coal seams, the roof was extremely broken and the collapse range of overlying strata continued to increase in irregular form.INTRODUCTIONThe thick coal seams occupy 44 percent of coal reserves in China and account for 45 percent of the gross domestic coal production. There are three main methods for extracting the thick coal seams: sublevel mining, large height mining, and longwall top-coal caving (LTCC) (Wang, 2009). Due to the rapid development of LTCC in the past two decades, it has become the most extensively used mining method. It possesses the advantages of high-production, high-efficiency, low development ratio, and low-cost (Yang, Zhang, Chen, and Zhengyang, 2016; Wang and Zhang, 2015). Baiyinhua coal mine's coal reserves are full of uniformly distributed thick coal seams, with the minable thickness of the main coal seam between 25 to 40m, i.e. the main coal seam is an ultra-thick coal seam. Sublevel longwall top-coal caving (SLTCC) which is an efficient method for extracting the ultrathick coal seams has led to multiple disturbances Xie, Chen, and Wang, 1999; Singh and Singh, 1999; Xie, Chang, and Yang, 2009. Therefore, using the case of Baiyinhua coal mine, the movement features of overburden strata and development characteristics of the three zones in ultra-thick coal seams were studied by physical and numerical simulations (Qian, et al, 2003; Qian, 1994)."

Jan 1, 2016

By Gary L. Hundley

The Bureau of Mines has devised a procedure to recover chromium chemicals from low-grade domestic chromites, which contain silicon and aluminum impurity levels that are too high to permit processing by present industrial processes. The Bureau procedure consists of reacting chromite with molten sodium hydroxide (NaOH) under oxidizing conditions to form sodium chromate (Na2Cr04). The reaction product is leached with methanol to remove the majority of the unreacted sodium hydroxide, then with water to remove the sodium chromate and the remainder of the sodium hydroxide. The sodium chromate product is recovered by evaporative crystallization from the aqueous solution. This report presents results of laboratory tests to determine the optimum fusion conditions and the chromium extractions obtained from several domestic chrotdte concentrates. These concentrates are from a variety of sources, including the Stillwater Complex in Montana, Kanuti River-Caribou Mountain, Red Bluff Bay, Kenai Peninsula, and Kodiak Island areas in Alaska, deposits in northern California, and a nickel-cobalt laterite from southern Oregon. All of these concentrates were successfully treated by the Bureau procedure. The best chromium extrac-tions obtained for each of these materials ranged from 69.5 to 98.9 pet.

Jan 1, 1985

By Sung-Ryul Kim, Woong-Jong Park, Juhyung Lee, Si-Hoon Lee

"A bucket foundation has been considered to be a potential foundation technology for offshore wind turbines. In this study, a series of 1-g model tests were performed to analyze the accumulated rotation of suction bucket foundations under long-term cyclic horizontal loads. The model suction buckets were made to have the embedment ratios of 0.5 and 1. The dry model ground was prepared to have two different soil densities by air-pluviation method. A horizontal cyclic load over 104 cycles was applied varying the loading amplitude. Test results showed that the accumulated rotation of the bucket foundation increased with the increase in the number of cycles and load magnitudes. Based on the model test results, a new equation was proposed to evaluate the accumulated rotation of the bucket foundations in sandy ground under long-term cyclic horizontal loads.INTRODUCTIONRecently, a bucket foundation has been considered to be a potential foundation technology for offshore wind turbines. In terms of economy, a bucket foundation has been considered to be an economical foundation type at sea beds where ground condition is clay or medium dense sand.A bucket foundation resembling a bucket is a kind of suction-installed foundation units. It is a skirted steel foundation which is open at the lower end and closed at the upper end by a lid. The embedment depth ratio (L/D) of a bucket foundation is usually less than one. Figure 1 shows an example of a bucket foundation. Offshore wind turbines are subjected to long-term cyclic loading by wind or currents. A bucket foundation is installed in soil grounds, so the long-term cyclic loading may induce the accumulation of soil deformation.In this study, the accumulated rotations of the bucket foundations in sandy ground were investigated under long term cyclic horizontal load. The number of cycles up to 104 cycles was applied varying load magnitude. The accumulated rotations of the bucket foundations in sandy ground were analyzed based on the test results."

Jan 1, 2016

By V. Ramachandran

In view of the increasing environmental regulations that have been promulgated in the last 30 years, non-ferrous smelters and refineries have learnt to handle effectively the process waste streams that need to be bled from the system for impurities' control The cations of concern are copper, lead, zinc, cadmium, mercury, thallium, nickel, silver, sodium and potassium. Anionic species of arsenic and selenium also need to be addressed, Sulfates and chlorides-not a major concern at present-have come under scrutiny in the recent past. The current paper reviews several treatment options with reference to a) types of waste streams processed b )process chemistry c)discharge options and recovery of treated water and d) sludge disposal The long term goal of any smelter and/lor refinery should be to achieve zero liquid discharge from the plant. Methods to obtain zero discharge are discussed.

Jan 1, 2003

By Marwa Nabil, Alaa A. Ata

"Recent developments in the analysis of piled rafts has incorporated the load sharing of the raft and the piles to support the superstructure. In the piled-raft system, piles are cast monolithically with the raft and the load is partly transmitted by the raft to the soil directly below it, and partly by the piles to more competent deep soil. While these piles are effective in increasing the bearing capacity and reducing the settlements, they often lead to significant straining actions at the pile head-raft connection which may constitute the weakest link. An attempt to provide a more economical solution, that at the same time overcomes this weak link, is to disconnect the pile heads from the raft and introduce an intermediate cushion of compacted fill. In this case, the piles are considered as reinforcement to the subsoil and will also act as settlement reducers. This paper investigates the load transfers mechanism of the unconnected piled raft with cushion using ABAQUS finite elements Program. The main objective is to provide an in depth analysis of the raft–soil–pile interactions in multi-layered soil under static and seismic loads. The investigated system provides an economical alternative for traditional connected piled raft foundation, where there is no need to reinforce the piles, no need for pile head demolition or expensive waterproofing of the pile head connection. Cost analyses of unconnected versus connected piled raft systems confirmed a cost savings in the construction that may reach from 50 to 70 percent.INTRODUCTIONDesigners around the world have gained more confidence to use the piled-raft as a more realistic system where the raft and the piles share transferring the superstructure loads to shallow and deep soil layers. A further advancement is to use unconnected piled rafts as another practical and economical alternative to the traditional piled rafts. Unconnected piled raft is also synonymous to settlement reducing piles; or simply, soil improvement piles. Liang et al. (2003) has extended the concept of pile-raft-foundation to a new type of foundation called composite piled raft foundation or unconnected piled raft foundation. The foundation is composed of a sand/gravel cushion sandwiched between the raft and piles. The piles group may contain short and long piles. The short piles are constructed of flexible materials such as soil-cement columns or sand-gravel columns, and are used mainly to improve the bearing capacity of shallow soft soil; the long piles, which are made of relatively rigid materials such as concrete, and their main function is to reduce settlements. The cushion plays an important role in mobilizing the bearing capacity of the subsoil and in modifying the load transfer mechanism of the piles. In Shanghai, China, this system of unconnected piled raft has proved to be quite suitable and effective in coastal areas, where deep soft soil deposits exist."

Jan 1, 2016

By Peter N. Calder

The selection of a slope angle for an open pit in rock has often been made without the benefit of a comprehensive engineering study. This is largely due to the fact that the hardware and procedures necessary for such a study have not been available. Recently this situation has been reversed. The application of borehole television and terrestrial photogrammetric devices has made possible the accurate determination of rock joint structure, on which stability calculations can be based. Another important aspect is the evolution of practical methods of conducting in-situ rock joint strength tests.

Jan 1, 1971

By F. Sillers, R. T. C. Rasmussen

"INTRODUCTION This is the fourth report of investigations dealing with the cooperative tests between the Bureau of Mines and industry on the use of electrolytic manganese in steelmaking. The first report dealt with the use of electrolytic manganese in the manufacture of stainless steel 3/ the second with its use in acid electric steel practice, 4/ and the third with its use in low-carbon basic open-hearth steelmaking. 2/ A résumé of those investigations E7 appeared in the magazine STEEL. 5/ The present report deals with the use of electrolytic manganese in the manufacture of four types of stainless steel and the new Timken 16-25-6 alloy. The Bureau of Mines supplied The Timken Roller Bearing Co. with 62,000 pounds of electrolytic manganese for use in the tests.The electrolytic manganese was produced at the Bureau of Mines pilot plant, Boulder City, Nev., by the process developed by the Bureau and described in Bulletin 463, Operation of Electrolytic Manganese Pilot Plant, Boulder City, Nev., by J. H. Jacobs. J. W. Hunter, W. H. Yarroll, P. E. Churchward, R. G. Knickerbocker, R. W. Lewis, H.A. Heller, and J. H. Linck. The workcarried out under the direction of R. S. Dean, formerly assistant director, Bureau of Mines, and R. G. Knickerbocker, formerly chief, metallurgical branch, as part of a long-range program involving the development, manufacture, and use of manganese from domestic ores. Preliminary arrangements for the plant tests were made by the late A. A. Dow. 7/"

Jun 1, 1947

By L. H. Adami

The heats of formation of anhydrous cadmium sulfate, cobalt sulfate, copper sulfate, nickel sulfate, and zinc sulfate were determined by hydrochloric acid solution calorimetry. The values at 298.15° K for formation from the metal, rhombic sulfur, and oxygen gas follow (cal/mole): CdS04J -222.0 ± 0.3; CoS04, -212.0 ± 0.4; CuS04) -183.4 ± 0.6; NiS04, -208.1 ± 0.2; and ZnS04, -233.1 ± 0.2. Corresponding heats of decomposition to form the metal oxide, sulfur dioxide, and oxygen were derived from these results; heats of decomposition to form the metal oxide and sulfur trioxide were also derived.

Jan 1, 1965

By Fredrick L. Johnson

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied 25,640 acres of the 29,680-acre Devil?s Garden Lava Bed, 21,040 acres of the 28,660-acre Squaw Ridge Lava Bed, and 9,100 acres of the 12,600-acre Four Craters Lava Bed Wilderness Study Areas (OR-D01-D02, OR-001-003, and OR-001-022, respectively) in order to evaluate their identified mineral resources. The study areas are located in Lake County, OR, about 50 air miles southeast of Bend. No mineral resources were identified in the three study areas. The areas are almost entirely underlain by recent lava flows. Cinder cones occur in each of the areas; however, the best cinder occurrences are in the Four Craters Lava Bed study area. Slab lava, of facing stone quality, is scattered throughout the Devil?s Garden Lava Bed study area, and to a lesser extent, in the Squaw Ridge Lava Bed study area.

Jan 1, 1987

By Laird Crocker

This report describes a study of beryllium recovery from sulfate leach liquor by di-2-ethylhexyl phosphate (EHPA) solvent extraction in conjunction with caustic stripping. The work was one phase of Bureau of Mines research on process development for Spor Mountain, Utah, ores. Solution for the solvent extraction studies was prepared by sulfuric acid leaching of ore containing 0.6 pet BeO, Before solvent extraction of beryllium, the leach liquor was treated to prevent coextraetion of iron by either (1) removal of ferric iron by amine solvent extraction or (2) reduction of ferric iron to nonextractable ferrous iron by treatment with sulfur dioxide. Beryllim was extracted from the aqueous leach liquor by countercurrent multistage contacting with a kerosine solution of EHPA. The loaded organic solution was stripped with sodim hydroxide solution. Subsequently, beryllium hydroxide was precipitated by boiling the sodium beryllate strip solution and converted to beryllium oxide of 98 pct BeO-grade by calcining. Material of this grade can be directly processed into beryllium-copper alloy or be used as starting material for further refining to produce high-purity, nuclear-grade beryllium. Over 90 pct of the beryllium contained in the leach liquor was recovered as beryllia.

Jan 1, 1963

By Nick Derick

The continued growth of steel production in the Western States is contingent upon the development of new iron ore sources. Recent development of economical techniques for concentrating and agglomerating taconites has focused attention on the low-grade magnetite deposits near Atlantic City, Wyo., as potentially important sources of iron ore for blast furnace smelting. Therefore, the Federal Bureau of Mines has made comparative evaluations of blast furnace burdens that incorporate pellets produced from Atlantic City concentrates. The Bureau also has evaluated the relative effect of Utah coke on blast furnace performance, using a high-quality Eastern coke as a basis for comparison. This work was done in the Bureau's experimental blast furnace at Bruceton, Pa. Tests determined the maximum wind rate that could be used while a continuous stock movement was maintained in the furnace. The furnace was operated at wind rates ranging from 800 to 1,400 std. c.f.m., them maximum limit of the blowers for the 1.75 in.-diameter tuyeres used. Using a normal Utah ore burden and Utah coke, the furnace went into a tight hanging condition with a wind rate above 950 std, c.f.m. Using the experimental pellet burden again with Utah coke, the wind rate could be increased to 1,000 std, c.f.m. and probably to 1,050 std. c.f.m, before tight hanging occurs. This represents an increase of 5 to 10 pct. in the wind rate. The experimental results indicate an accompanying increase of iron production, as much as 8 pct.

Jan 1, 1961

By Mark Jolly

"Over the last ten years or so many man hours have been dedicated to developing methods for simulating shape casting processes. The majority of the methods developed have been devised by a combination of computer, mathematics and materials specialists often with limited knowledge of foundries and foundrymen. As a result of this it would appear that although there are many software packages for the foundryman to use there still exist fundamental misunderstandings as to their usefulness and suitability within the foundry.The paper aims to identify how well current software packages perform. The relationships between physical phenomena, practical defects and software capabilities are presented. Some discussion of the use of criteria functions is also presented. Finally issues arising from the postprocessing of results are discussed as the presentation of the results to the lay-person in simulation techniques is possibly one of the most important aspects in influencing the adoption of this type of software in the foundry community."

Jan 1, 1999

By J. J. Burns

Disasters such as occurred at Oppau, Germany, in 1921, at Tessenderloo, Belgium, in 1942, and in this country at Texas City, Tex., in 1947 clearly indicate the explosive hazard associated with the manufacture, storage, and transport at ion of ammonium nit rate The importance and extent of the hazard may be Judged from the large amount of ammonium nitrate produced and transported annually in this country. Between July 1, 1947, and June 30, 1948, it was estimated that the United States produced 461,528 tons of ammonium nitrate commercially for agricultural purposes alone .5/ In addition, U. S. Army Ordnance plants have manufactured and shipped 779,730 tons of ammonium nitrate fertilizer to Germany, Japan, and Korea.6/

Jan 1, 1953

By Raymond E. Healy

Circuit samples from the HBMS concentrator were assayed for l5elements, and image analysis was done to determine the modal quantities, grain size distributions and liberations of the minerals. Material balancing was done on these data to determine distributions of the minerals in each concentrator stream. The ore was mined during the waning phase of mining and is diluted with backfilled copper smelter slag. The mill feed grades 1.0 wt% Cu and 1.8 wt% Zn. The slag silicate phases contain approximately 1.5 wt% Cu and 6.5 wt% Zn; therefore the Cu and Zn head grades due to chalcopyrite and sphalerite, are only 0.9 wt% Cu and 1.2 wt% Zn, respectively. The recovery of Cu in the Cu-concentrate (Cu-conc.) is only 77.5 %, whereas that of chalcopyrite is 89.2 %. Similarly, the recovery of Zn in the Zn-concentrate (Zn-conc.) is only 40.2 %, whereas that of sphalerite is 71.0 %. The slag accounts for approximately 60 % of the Cu, and 85 % of the Zn in the tailings. The main loss of chalcopyrite is as unliberated grains to the tailings, and the main loss of sphalerite is as free grains to the Cu-concentrate and as unliberated grains to the Cu-concentrate and tailings. Approximately 85 % of the chalcopyrite and sphalerite lost to the tailings. accounting for 8 % and 10 % of the respective minerals in the concentrator feed, occur as middling and sub-middling grains. Extremely fine regrinding would be required to liberate these minerals.

Jan 1, 1989

By B. Qiu, Y. Luo

Longwall and/or room-and-pillar mining operations in multiple coal seams may not only induce subsurface and surface subsidence but also cause interactions between these mined coal seams. The interaction might destabilize underground mine structures and subsequently induce additional strata movements. Mathematical models to use the predicted subsurface deformations to assess the interactions and the consequences have been developed. The models are incorporated into a computer program, CISPM-MS, for predicting the final surface movements and deformations, as well as the mining interactions associated with multiseam coal mining operations. It predicts final surface movements and deformations caused by the individual mining operations and by the interactive effects. The program can also be used to assess mine structural stability in multiseam mining operations. The paper presents the developed interaction models and their application in surface subsidence prediction caused by multiseam mining operations. A case study involving mining in two coal seams, using longwall and room-and-pillar mining methods, respectively, will be used to validate the program.

Jan 1, 2013

By Ari I. Kogut

Impurity minerals in fluorspar ores and concentrates from a deposit in Southern Africa have been studied by reflected light, transmitted light, and cathodoluminescence microscopy. The principal impurities are quartz, calcite, aegirine, apatite, ankerite, magnetite, goethite, and synchysite [Ca(La,Ce,Nd)(C03l2Fj. Cathodoluminescence microscopy was found to be very useful in studying the character of the fluorite and especially for recognizing the presence of apatite and calcite impurities. Fluorite exhibits blue, calcite shows yellow, and apatite has white, light purple, and pink cathodoluminescence. The cathodoluminescent character of apatite varies with its geological environment and position in the orebody. The results of this microscopic study show that phosphorus present in flUorite concentrates occurs principally in binary locked apatite-fluorite particles. Successive fluorite cleaner concentrates contain progressively smaller amounts of locked apatite-fluorite particles. Free apatite has been effectively partitioned to the final tailings.

Jan 1, 1995

By Parry. V. F.

"INTRODUCTION Coal is a compressed mass of heterogeneous, macerated, metamorphosed plant remains that have collected in the earth's crust. Probably no two beds of coal have identical properties, and different parts of the same bed may vary considerably when measured by some of the many empirical tests that have been developed to classify or differentiate the properties of coal. Because of this great variability in properties, the commercial processing of coal to produce coke and byproducts has developed largely as an art based on experience, rather than as a science. Much empirical chemical research, however, has been and is being conducted on coal carbonization, and this work is of practical value in obtaining larger yields of gas and byproducts and in the improvement of the physical properties of the coke.Both ultimate and proximate analyses have been used for correlating purposes. 3/ In the United States the proximate analysis is used for the classification of coal according to rank and grade. The proximate analysis can be employed usefully in the coal—carbonization industry because separation of the combustible matter of coal into volatile matter and fixed carbon is, in fact, a small carbonization test conducted on 1 gram of coal heated in a platinum crucible.Small—Scale Laboratory Coking Tests,Many empirical tests have been devised for determining the coking properties and measuring the yield and quality of gas and byproducts obtainable from various coals. These tests, made on samples ranging from 25 grams (about 1 ounce) to 5 kilograms (11 pounds), furnish information that is roughly proportional in practical value to the size of the sample carbonized. However, the cost of the carbonization test also increases with the amount of the sample, so that for preliminary surveys of a number of coals, samples of 25 to 1,000 grams usually are employed."

Dec 1, 1939

By Stanko Nikolic

The Top Submerged Lance (TSL) technology, developed in the 1970s, is now widely used for the processing of a range of materials. TSL technology for continuous converting was first patented in the 1990s. The process is based on the use of calcium ferrite slag. Although this slag system had been applied elsewhere the phase equilibria had not been thoroughly investigated. This lead to a collaboration between the Process Technology group of Mount Isa Mines, now part of Glencore, and the Pyrometallurgy Innovation Centre (PYROSEARCH) at The University of Queensland. Through multiple research programs this complex system was successfully investigated. The results were then implemented within thermodynamic modelling tools. This combined new knowledge was then applied to the design and industrial implementation of the TSL continuous converting technology, ISACONVERT™. This paper describes the key findings of the research and how this was applied to the industrial implementation of the technology.