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By M. Troyer

A coal shuttle car equipped with a pulsed laser optical ranging system to provide guidance for an automatic steering system was tested in production coal mining. Test results are presented for the two mines where testing took place, and some operator's reactions are included. Automatic steering control keeps the car cantered in an entry, and automatic turns are made at intersections as signaled by the operator. All other controls-tram, conveyor, brake, etc, remain manual and require operator control. Complete override of steering while in the automatic mode is retained by the operator, who may grab the steering wheel at any time and turn in opposition to the automatic signal by applying about 10 foot-pounds of torque.

Jan 1, 1976

By G. B. Quaye

The deep level gold mining environment is characterized by high stresses that give rise to intense mining induced fracturing of the rock mass surrounding the stopes. In a geologically disturbed region where the intensity of mining induced stress fracturing is high, the degree of faulting and/or the frequency of other geological features such as joints may pose serious strata control problems. Unfavourable intersection of these discontinuities namely, faults, joints and mining induced stress fractures tend to divide the immediate hangingwall into unstable keyblocks which, if not supported, may result in extensive falls of ground. Effective support strategies therefore demand detailed investigation of the predominant inclinations and orientations of these discontinuities. The orientations and inclinations of these discontinuities surrounding a deep level stope have been measured. The results are projected onto the lower hemisphere of a stereographic net to determine the factors that contribute to the falls of ground in the stope. The analyses reveal that unfavourable intersection of these discontinuities divides the immediate hangingwall into unstable wedges that may become dislodged between support units.

Jan 1, 1998

By Roy T. Sorensen

As part of its mission to maintain an adequate supply of minerals to meet national needs and maximize mineral production from domestic sources, the Bureau of Mines is investigating the recovery of alumina by hydrochloric acid leaching of kaolinitic clay. Most iron impurities are leached from the clay along with the alumina and must be removed before or during crystallization to aluminum chloride hexahydrate. The thermal decomposition step then provides an alumina product of acceptable iron analysis. Miniplant studies of a Bureau-developed solvent extraction technique, using a tertiary amine in kerosene diluent, have demonstrated that the iron content in aluminum chloride leach liquors can be reduced to levels of less than 0.007 wt-pct (7 ppm), expressed as Fe203. Entrained and dissolved organic matter in the purified pregnant leach liquor from the solvent extraction circuit can be reduced to less than 2 ppm by using a fabric-packed coalescer and subsequent activated carbon treatment. Investigators discovered that a steady buildup of zinc accumulated in the solvent phase within the extraction circuit, proportional to the amount of leach liquor treated. The solvent phase zinc analysis increased by 0.01 wt-pct ZnO for each 1,000 gal of pregnant leach liquor purified.

Jan 1, 1981

By Alain Bouchard, Germain Labonté, Jim Barrett

"Mill feed materials that are not run-of-mine ore are often a challenge for mineral processors and tend to accumulate in stockpiles, where they remain unprocessed for many years and become “slow moving inventories”. During a complete re-evaluation of the Clarabelle Mill operation (38,000 ton/day capacity) in 2000, it was concluded that there was an opportunity to assemble a 5,000 ton/day custom circuit to treat such stockpiles in the equipment that remained available during regularly scheduled maintenance shut-downs.This project was part of the larger Mill Redesign Project and involved testing the intended flowsheet under a number of operating scenarios for the first material to be treated: spent refractory bricks. The laboratory focus was on how to maximize returns using the available equipment and reagents.The circuit was successfully commissioned in the fall of 2000. As the brick stockpile was depleted, other potential feeds were evaluated at the laboratory, as well as in the new custom circuit itself. Processing of the spent refractory brick has yielded a significant contribution to the profitability of INCO. Significant opportunities lie ahead for generating more value from other slow moving inventories.INTRODUCTIONIntegrated mining operations tend to have slow moving inventories along the path from the mines to the finished products. Spent refractory bricks from furnaces and converters and furnace bottoms are materials that often end up in long-tern stockpiles. Such stockpiles are a challenge, although they represent small tonnages on an annual basis, because they are unique materials, which cannot be readily brought into the process at a rate anywhere near that at which they are produced, due to the high contents of deleterious components such as chromite or magnesia. Accumulation over years will eventually yield a metal inventory worthy of consideration given the right opportunity, such as availability of spare equipment or peak metal prices."

Jan 1, 2002

By Dale Lens, W. S. (Wayne) Cusitar

"The use of continuous loading and conveying technology for mining is currently practiced in relatively few mining environments and, even in these cases, on a non-exclusive basis. For the most part, and particularly in hard rock mining, appropriate equipment technology has only recently been developed for continuous loaders, mobile low profile crushers and flexible face conveyors. Mining R&D work by Inco Limited has promoted the development and proving of a loader suited to hard rock conditions and capable of sustained loading rates of500 tonnes per hour. Current R&D work at Inco will test the production capabilities of a low profile mobile crusher by CMS/Eagle and a flexible/ mobile face conveyor system by DME. This follows successful production testing of the Belt Bender concepts in potash mining in Saskatchewan and the development of enhanced extensible conveyor equipment features by DME. Numerous applications are seen for variations of the LCC technology in soft rock, hard rock and surface mining environments. Introduction In some respects, this paper is an announcement of new technology which has the potential to bring revolutionary change to the mining industry. It is also the story of technology transfer, in which mining concepts that have developed independently in underground soft rock and hard rock mines and in surface mining operations are being brought together for a common benefit. It is also the story of key developments in equipment technology which 'complete the cycle' of cooperating technical capabilities to enable the revolution to begin. The phrase ""technological revolution"" requires some defmition: an equipment innovation, or invention, or improvement, will only be revolutionary if its use gives rise to a significant new mining practice."

Jan 1, 1987

By S. Vorberg, J. Preussner, B. Fischer, U. Glatzel, R. Völkl, M. Wenderoth

Pt-Al-X alloys have shown good mechanical properties and adequate oxidation resistance. Starting from a promising Pt-Al-Cr alloy, the influence of Ni additions was investigated. After ageing finely dispersed precipitates are observed. Nb, Ta, Ti and Re increase strength when added as partial substitute for Al. Minor additions of B increase creep resistance and rupture time remarkably, owing to strengthening of the grain boundaries. The evolution of the alloy development programme as well as selected properties of the multi-component Pt-base alloys are presented.

Jan 1, 2006

By Sir Robert Hadfield

SINCE the writer has been intimately connected with the development of manganese steel for many years, some remarks upon the early work with regard to the rolling and forging of this material might he of interest, and particularly as to the question of rails of special quality and of superior wearing qualities. In a paper on Iron Alloys, with Special Deference to Manganese Steel, read before this Institute at the International Engineering Congress in Chicago in 1893,1 the writer mentioned that, about 20 years ago, his firm in Sheffield produced railroad material, such as tires and axles, of forged and rolled manganese steel, thus showing that this product could be manipulated and worked up into the various required forms. The tires illustrated in the paper referred to above formed a particularly difficult class of work to produce in a special steel, but no special obstacles were met with Although there was no difficulty at that time in making and producing manganese steel in various forms, forged, rolled or pressed; nevertheless, on account of its higher expense, sufficient encouragement

Jan 2, 1914

By Herman O. Ankenbruck

Analyses of statistical data indicate that haulage accidents are one of the largest sources of injuries and fatalities in underground coal mines, and that the rate of accidents in transportation has been increasing during the past few years. These previous analyses were performed by correlating accident or fatality data at a rather high level of miner activity. In this present investigation, underground surveys were made by observing conditions and activities in some detail at a rather low level of activity in an attempt to understand factors contributing to hazards in the specific situations observed. The aim of the current study was to derive preventive measures that might obviate the hazardous conditions and unsafe acts observed; and, following this, to provide recommendations for additional research and development to reduce accident potential in underground transportation. The major project tasks are diagrammed together with the task outputs in figure 1-1. Initially, a preliminary study of ell underground haulage operations was performed in order to establish the kinds of data needed and to provide the rationale leading to the data requirement. At the same time, the various types of haulage equipment used for each operation were defined. A preliminary analysis of each type of haulage operation was performed in order to establish the sequence of tasks required to operate haulage equipment. These tasks were transferred directly onto observation forms, and were used in developing interview forms. In parallel with the task analysis, a review was made of accidents and hazards that might occur during each type of operation.

Jan 1, 1975

By J. M. Kuchta

Bench-scale test methods were developed by the Bureau of Mines for use by the Department of Transportation in the classification of solid and liquid oxidizers. A burning rate test is recommended for evaluating the fire hazard of solid inorganic oxidizers when mixed with a red oak sawdust as the reference combustible. A spontaneous ignition test is proposed for evaluating liquid and solid inorganic oxidizers which may decompose violently or ignite spontaneously when unmixed or mixed with the wood sawdust under unconfined conditions. Test results are compared for various representative oxidizers and a classification system is proposed for use in the government transportation regulations.

Jan 1, 1972

There has been a substantial increase in the use of rubber-tired front-end loaders in the mining industry in recent years. Concurrent with this increased usage, in the period of 1966 to 1970, there were at least 74 mining industry fatalities involving front-end loaders, or (on the average) in excess of one fatality per month. When the usage of front-end loaders by the construction industry and other industries, organizations, and agencies, such as the Government (i.e., Department of Defense), along with the uncounted numbers of serious, but non-fatal accidents, are included in the picture, the safety record for front-end loaders, of necessity, becomes a serious subject for study. There is an urgent need for attempts to be made to eliminate or reduce the number of safety hazards; to decrease the confusing diversity of controls designs found on present front-end loaders; to improve the maintenance and operating procedures; to formulate better personnel policies; to increase management and official awareness of the extent of the problem, in both industry and the Government; etc.; in order to decrease the number of accidents. Part of the problem may be traced to the fact that the operator of a front-end loader is frequently designated a "heavy equipment operator." This implies that he is automatically qualified to operate any model, of any manufacturer's, wheeled or tracked, front-end loader as well as many other types and classes of heavy equipment. Contrary to automotive practice, the complement of primary operating and emergency controls varies widely from model to model, as well as from manufacturer to manufacturer. Not only are certain controls present on one front-end loader model and absent on others, but there are significant differences in the modes of control operation, in the functions performed by superficially similar controls, in the location of the various controls, etc.

Jan 1, 1973

By Brenda M. Dixon

A matrix analysis of the differences between the camps and communities associated with the Britannia Mine is used to develop an analytical tool. The tool is intended to assist the mining industry as it embraces the many facets of sustainable development. A case study is used to support the identification of key factors that may predict the sustainability of a new mine town. Sustainable communities, like Britannia Beach, are discussed in the context of three pillars of sustainability: value of mining products to society; creating wealth; and, environmental integrity. A sustainable mine town may be viewed as a socio-economic asset as well as an asset to the mining industry.

May 1, 2006

By L. A. Cornish, L. H. Chown, M. Matema, R. Süss, L. Glaner, A. Douglas

Mintek has been developing Pt-based alloys for high temperature applications in aggressive environments, for example, land-based turbine engines, to replace the currently used nickel-based superalloys (NBSAs). The Pt-based alloys have a similar structure to the NBSAs, and since Pt is more chemically inert and has a higher melting point, the Pt-based alloys can potentially be used at higher temperatures. The greater chemical inertness of the Pt-based alloys compared to the NBSAs means that coatings can be simpler, or perhaps not even used at all, depending on the environment. TEM work was done at NIMS, Japan, to investigate the changes in the microstructure o f Pt-Al and Pt-Al-Ir alloys at elevated temperatures using in-situheating up to1100°C. Initial casting trials showed that work needs to be done to optimise casting parameters before commercialisation can take place. Room temperature tensile tests were performed and results were variable mainly due to microstructural differences. The alloy hardnesses were in the order of 300-350HV with ultimate tensile strengths of ~800 MPa and elongations of less than 10%. These results are comparable to other alloys used at high temperatures, which is very encouraging. Keywords: platinum, super alloys, hardness, tensile

Jan 1, 2006

By M. F. van der Merwe

Anglogold Ashanti?s Kopanang Gold Plant (previously No. 9 Gold Plant) treats ore from Kopanang and Tau Lekoa shafts. The plant is twin streamed and has dedicated treatment circuits, from milling to final product, for each shaft. Waste rock material is used to compensate for the mill gap on both streams. Each stream consists of three 4.85 m x9.15 m ROM mills in closed circuit with a single stage hydrocyclone, milling an average of 7 000 t per day. The liner configuration in each mill consists of six rows of 30 grid liners along with rectangular lifter bars. The topic of gold lock-up is not new and has been investigated and reported on many times, both within Anglogold Ashanti and the broader mining industry. Although the lock-up mechanism is understood, its measurement is neither practical nor precise. The initial lock-up in a new liner and the release as the liner wears down cannot be accurately quantified. Previous test work carried out on Kopanang Gold Plant (with a ?gold scanner?) measured the natural gamma radiation emitted by uranium. This radiation is in proportion to the mass of concentrate locked up in the grid liner pockets, as well as between the cast-on backing plate and the shell. The ratio of concentrate lock-up was estimated as 35% behind the liners and65% in the pockets. Mill gravity concentrates are recovered during routine relining operations from behind the grid liners at Kopanang Gold Plant. Prior to relining, the liners tend to release the concentrate from the pockets as the liners wear. Historical Kopanang data from actual ?mill gold? smelted indicates that an average of 29 kg gold is recovered from behind each row. This indicates a total lock-up of 250kg gold per mill. This locked-up gold should preferably be minimizedor eliminated for the following reasons: ?The cyclic build-up and release of gold in mills complicates accounting ?Gold concentrate arising from liners is a security risk and creates a major mechanism for gold theft ?Loss of interest on the value of 250 kg fine gold is significant and was a major driver for the project. These factors led to the need to develop techniques to eliminate or at least minimize the gold lock-up in the mills. Wave liners, with rubber inserts, have been successful in eliminating lock-up, and were tested at Kopanang Gold Plant in November 2000. However, due to increased load-slip and high wear rates associated with these liners, this option proved less economical in terms of liner wear. Grid liners, with rubber-filled pockets, demonstrated a very high wear life and eliminated pocket lock-up. This system was successfully trialed in January 2003, but unfortunately did not prevent lock-up behind the liners. Current developments have resulted in a system that eliminates both pocket and backing plate lock-up. The conventional grid liner design has been modified to remove its steel backing plate. Rubber inserts that are integrated onto a rubber backing plate, have been designed to be used with the newly modified grid. The backing plate and grid pockets are now completely occupied by rubber, thus completely eliminating concentrate build-up around the new grid liner system installed in November 2003. Results to date are promising and liner life is expected to exceed conventional performance.

Jan 1, 2005

By L. T. Stanley

A method is described whereby the behavior of the front is approximated when gas is injected into a thick reservoir having reasonably homogeneous properties. The method is applied to the Abqaiq field of Saudi Arabia. The producing member is the Arab-D, a high-permeability calcarenite which has no continuous betlding planes. Field performance indicates the injected gas to be partially miscible with the reservoir oil because gas volume factors experienced are lower than those predicted by the gas law. Eqlrilibril~m calculations confirnz ihis and also show that the volume factor may vary appreciably, depending on the relative quantities of oil and gas in contact in the reservoir; consequently, volutnetric balances are made for the purpose of determining the behavior of the gas volume factor during injection history. The effect of gravity segregation on position and shape of the gas front is approximated by dividing the producing section into three zones vertically and tracing the movement of the average interface in each zone, with counterflow of oil and gas taking place betweell zones behind the front. This results in a gas front that advances more rapidly along the top of [he formation than along the base, producing an "umbrella" effect in cross section that becomes more pronounced as the front progresses. The calculations cover the gas-injection period of Abqaiq field history through 1958, and the position of the gas front is plotted at one-year intervals. Finally, some comparisotls between the calcrlated fronial position and the gas-oil contact as Measured by neutron logs are made. INTRODUCTION Fig. 1 is a structure contour map of the Abqaiq field. For analytical purpcses, the field has been divided into two areas designated A and B, as shown on the map. Gas injection into Area A was begun in early 1954 into two wells located near the crest of the structure on the north-south axis of the anticline. During the period covered by this paper, the average injection rate has been 122 MMscf/D with a maximum sustained rate of 160 MMscf/D. The reservoir pressure has been maintained at 2,450 psig since start of gas injection. The reservoir originally was undersaturated but, prior to pressure maintenance, the pressure was drawn below the bubble point in most of the Area A section, creating an in-place free-gas saturation of 8 per cent at the crest of the structure. The average critical gas saturation is 13 per cent established by laboratcry core tests. That the entire reservoir remained below critical gas saturation prior to gas injection is borne out by the fact that none of the crestal wells have exhibited high gas-oil ratios during production history. The Area A reservoir is a carbonate section about 200-ft thick having average porosity and permeability of the order of 22 per cent and 500 md, respectively. The productive horizon is the Arab-D member of Jurassic age and is encountered at an average depth of

By Unal Artan

It is well known in the robotics community that the ability to determine the position of vehicles in real time is a key enabling technology required for automation, traffic management, and to ensure safety in the presence of multiple vehicles. Because of this, the introduction of global positioning systems (GPS) has had a remarkable impact on the surface mining industry, enabling real-time tracking of mobile assets, improved safety, and production optimization. Unfortunately, satellite-based GPS is not available underground. This paper reports on the preliminary results of a study to develop a robust method for globally consistent mapping of large-scale underground mine environments. We believe that this may additionally become the first step towards the development of a novel underground positioning technology. Presented are preliminary results from data collected at two underground mines using an Atlas Copco ST14 LHD machine.

Oct 1, 2009

Lower greenschist quartzo-feldspathic schists within the N-S trending Earnslaw Synform of the Upper Wakatipu area are pervaded by late-stage quartz filled extensional and extensional shear fractures, with quartz-scheelite lodes infilling normal faults. Exposed veins/lodes mapped over at least 1000 km2 define a paleoflow system developed during late metamorphic exhumation of the schist. Both veins and lodes have consistent angular relationships to the schist foliation independent of their location on the Earnslaw synform. Unfolding the synform leads to a regional subhorizontal foliation and a systematic set of subvertical quartz veins striking NNW extending over a depth interval >5 km, striking parallel to a set of normal faults hosting the quartz-scheelite lodes. The structures define an extensional regime with s1 sub-vertical, s3 oriented WSW-ENE, a low differential stress, and suprahydrostatic fluid pressures.   The quartz-scheelite lodes (<2 m thick) occupy faults which cross-cut the quartz veins, and are traceable for a few hundred metres, at most. The lodes consist of laminated and/or massive quartz, slivers of crushed and folded schist, random and discontinuous lenses of scheelite with clay selvages separating the lode from relatively undisturbed wallrock schist. Textural evidence suggests that slip developed incrementally with total displacement on faults during lode formation on the order of a few ten's of metres.   The distribution of Glenorchy veins demonstrates broad scale hydrothermal flow through low-permeability schist, channelled within dilatant mesh style structures comprising interconnected shear and extension fractures. Flow through the lodes was likely derived from the greater surrounding area via the interlinked network of fractures and focused into the low displacement shears. Available evidence suggests the system developed together in a uniform extensional stress regime toward the bottom half of the seismogenic regime.

Jan 1, 2001

By H. H. Wade, N. F. Schulz

The large quantities of iron-bearing materials, including taconite, semi-taconite,* and other low-grade ferruginous materials occurring in Minnesota and elsewhere, constitute an important potential source of iron. Satisfactory grade and recovery of iron ore concentrate cannot ordinarily be obtained from these ferruginous materials by simple methods of beneficiation. Iron is distinctive in that the free metal and two of its oxides [magnetite (Fe2O3) and maghemite (gamma-Fe2O3) ] are strongly ferromagnetic. The successful magnetic separation of natural magnetite from taconite has already been established on a commercial scale. The iron in semi-taconite, however, occurs largely as goethite (Fe2O3-H4O) and hematite (Fe2O3) which do not respond to ordinary magnetic separation methods. Magnetic roasting converts these iron oxides to magnetite, which can, after liberation, be magnetically concentrated. MAGNETIC ROASTING Hematite undergoes a stepwise reduction when exposed at moderately elevated temperatures to a reducing atmosphere containing hydrogen or carbon monoxide: Fe2O3? Fe3O4 ? FeO ? Fe Since the desirable product in magnetic roasting is Fe3O4, the conversion is halted after the first stage by controlling the reduction potential of the gas mixture with water vapor or carbon dioxide. The reducing gas mixture must be such that the oxygen partial pressure at the solid-gas reaction interface will be maintained intermediately between the oxygen partial pressures in equilibrium with Fe2O3 and Fe3O4 at the prevailing temperature. Because of the rapid increase in decomposition pressure of Fe3O4 with increase in temperature, the practical upper limit of useful reaction temperature is about 1400°F, above which over-reduction usually occurs in atmospheres containing hydrogen or carbon monoxide. On the other hand, useful reaction rates usually occur only above 800°F. Goethite reacts similarly except that the combined water probably has to be driven off thermally before the reduction to magnetite occurs. Iron carbonate must also be decomposed thermally to an oxide before conversion to magnetite. Iron silicates are apparently not amenable to magnetic roasting. The rate of penetration of the reaction toward the interior of a given ore fragment is dependent on the chemical composition and physical structure of the solid. Most ore fragments tested here reduced satisfactorily to 1/4-in. depth in less than 14 min at 1200°F. Some very dense fragments, however, were reduced to less than 1/32-in. depth under the same conditions. Determination of the optimum temperature, gas composition, ore fragment size, or time of exposure

Jan 1, 1961

By H. K. Lin

Deepwater discharges of sulfide flotation tailings have been practiced for several decades. Oxygen penetration and organic matter content in such environments are the two major factors that determine their reduction-oxidation condition and hence the rate of sulfide mineral dissolution under such discharge environments. In this study, the effects of solution redox potential and pH on the dissolution of some heavy metals from sulfide flotation tailings were examined. Zn, Pb and Cu concentrations in solution were all higher at a higher redox potential and lower pH. Dissolved Zn concentrations reached 100 ppm even at a low redox potential of 105 mV and near neutral pH after 33 days. Pb concentrations were below 2 ppm at 105 mV and near neutral pH after 165 days. At 105 mV, the Cu concentrations were below 0.2 ppm at near neutral pH after 165 days. At pH 2.3, the Fe concentrations were higher at 420 mV than at 105 mV. But at pH 6.8, the Fe concentrations were lower at 420 mV than at 105 mV, due to the oxidation of Fe2+ to Fe3+ and the subsequent precipitation of ferric hydroxide. Arsenic concentrations in solution were all less than 0.002 ppm. For Zn, Cu and Fe, no significant differences were observed between the tests in solutions prepared using seawater and those using distilled water. However, Pb concentrations reached higher levels in solutions prepared using seawater.

Jan 1, 2009

By Paul H. Lu

This Bureau of Mines report summarizes the analysis and eveluation of the field measurement results of a comprehensive ground control study conducted in a mechanized longwall coal mine in West Virginia. Emphasis is placed on the three basic ground control parameters: ground pressure, ground movement, and geomechanical properties. Specific topics include premining ground pressures, front-abutment pressure in the longwall panel, histories of pillar loading, differential roof-strata movement and bed separation, differential floor strata movement, entry roof-to-floor convergence, in situ moduli of rigidity of coal seam and roof and floor strata, and mechanical properties of coal and coal measures rocks.

Jan 1, 1985

By L. H. DeWald

During the examination of various commercial brands of copper wire bars, which had exhibited different degrees of adaptability for being drawn into fine gages of wire by the present-day high speed machine, it was found that each brand had a more or less characteristic crystal macrostructure. The extremes of these macrostructures are similar FIG. 1.-EFFECT OF METAL TEMPERATURE IN CASTING ON CRYSTAL MACROSTRUCTURE OF BAR. Reading from left to right, metal temperatures were 1166" C., 1149" C., 1132" C.. 1121" C., 1093" C. to the maximum variation shown in the photomacrographs reproduced in Fig. 1. As the various brands did not differ materially in chemical composition, it was concluded that the differences in structure were the result of variations in casting technique.

Jan 1, 1931