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As part of the Phase I study activity, a questionnaire was sent to a representative sampling of mining companies to obtain information on the uses, use conditions, personnel policies and other user concerns associated with front-end loaders. On-site visits to several of the mining companies were also parried out and the questionnaire was used during these visits as well. Five major areas were dealt with in the user questionnaire. These included: 1) Front-End Loader Critique - An open-ended form was employed to permit the mining companies to describe the particular things they liked and disliked about front-end loaders, in general, and/ or specific models in particular. 2) Usage - A form indicating the functions performed by front-end loaders and the numbers, makes and models of front-end loaders being used by mining companies. 3) Environment - A form where the user indicated the various types of conditions encountered in their use of front-end loaders. 4) Personnel - A form for describing factors pertaining to the qualifications of front-end loader operators. 5) Miscellaneous and Comments - A form permitting the user to comment on his feelings toward standardization of front-end loader operator stations.

Jan 1, 1973

By A. Sutton-Pratt

The African continent has been the most prolific producer of gold since mining began. Although most of this gold has come from South Africa, other countries have also been important contributors in the past. There is currently little production outside South Africa, Ghana and Zimbabwe, but the gradual globalisation of the industry over the past decade has resulted in growing interest in the region which bodes well for its future development. An outline is given of prospects and activity (or lack of it) in South Africa, Lesotho, Swaziland, Zimbabwe, Mozambique, Madagascar, Botswana, Namibia, Zaire, Tanzania, Kenya, Uganda, Rwanda, Burundi, Zambia, Malawi, Angola, Congo, Central African Republic, Gabon, Equatorial Guinea, Ethiopia, Eritrea, Djibouti, Somalia, Sudan, Chad, Libya, Tunisia, Egypt, Algeria, Morocco, Ghana, Ivory Coast, Liberia, Sierra Leone, Guinea, Senegal, Guinea-Bissau, Gambia, Mauritania, Mali, Burkina Faso, Togo, Benin, Niger, Nigeria and Cameroun

Apr 1, 1996

By R. A. Pyper, J. L. Hendrix

Laboratory leaching experiments were conducted to ascertain the effectiveness of acidic solutions of thiourea, CS(NH2)2, for dissolving gold from finely disseminated gold ores. The ore tested was from the Chipmunk ore body of the Northumberland mining district in Nye County, Nevada, USA. Extractions of up to 90% were attained from the ore. Extraction was shown to be dependent on thiourea concentration, ferric sulfate oxidant concentration, acid concentration, and leaching time. Optimum conditions were an ambient temperature leach near pH 1.0 utilizing 100 to 200 kg/ton thiourea and 50 kg/ton ferric sulfate for 8 to 24 hours.

Jan 1, 1981

By J. Douglas Causey

In 1987, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied a part of the 21,296-acre Million Hills Wilderness Study Area (NV-050-233) in order to evaluate its identified mineral resources. The study area is located in Clark County, NV, about 46 miles south of Mesquite, NV. The area is on the east edge of the Gold Butte mining district and has had minor production of copper and zinc from the Azure Ridge mine in the early 1900's. Assessment work was being done on the Esperanta claims, which covers the mine workings, in March 1987.

Jan 1, 1988

By E. K. Stanek

The field tests involved ten coal mines in which transients were initiated on the dc system from which the parameters of the dc mine electrical power system could be determined. The data processing involved the use of a Fourier Analyzer to filter noise and fit an exponential curve to the field waveforms. From this data analysis it was possible to find the dc system resistance, inductance and time constant. The survey of nationally recognized laboratories was conducted to establish that the recommended test criteria were practical. The development of test criteria for dc fuses used in mines was based on the measurement of parameters in the field, the survey of testing laboratories, literature searches, laboratory test, etc. A computer program was written to analytically predict the parameters measured in the field. This approach has limitations but reasonable agreement with field results was obtained. A brief laboratory testing program was carried out to verify the practicality of the recommended criteria and establish the accuracy of the conclusions concerning dc fuse performance.

Jan 1, 1984

The effect of composition on electrical conductivity (resistivity), viscosity and liquidus temperature of the slags encountered in electric smelting of PGM-containing suphide concentrates is reviewed along with the relationsip between slag composition, slag-matte separation and metal losses to slag. Optimization of slag composition at furnace temperature is attempted on the basis of opposite and parabolic trends of the viscosity-conductivity relationships of the slags. The importance of surface tension of slags is emphasized using available and estimated information, which are grouped into a useful correlation. These values are coupled with or incorporated into slag viscosity plots to illustrate the correlation between the two factors which influence slag-matte separation as well as refractory attack. The electrode in the slag-resistance furnace is the central factor in the design and operation of the furnace by its role of conveying the smelting power. The obvious parameters are the size and positioning in the slag bath, which are defined by slag resistivity, furnace resistance, cell constant and power input. The flow of heat generated by the electrode current determines the energy distribution and furnace dimensions creating viscosity profiles, which in turn affect flow conditions. Thus the flow of slag and matte isdiscussed in conjunction with the furnace geometry, stirring action of the electrodes, buoyancy and electromagnetic effects. The action of the electric furnace as a settler is discussed. The rectangular furnace is considered as a channel reactor in this analysis and the action of the electrodes is described to indicate a balanced settling rate in the area of electrode action. Discussion of the design and production capacity of the electric furnace with reference to operating current, power input, furnace dimensions and electrode size are based on considerations derived mainly from slag properties such as its resistivity, viscosity and liquidus temperature.

Jan 1, 2004

By T. C. Green

A two-phase program evaluated commercial proximity warning devices and then served to design and develop an automatic electrostatic field strength measurement device with improved performance. The Phase I program consisted of test and evaluation of three commercial proximity warning devices, all of which operate on the principle of electrostatic field intensity measurement for determining proximity to high voltage power lines. Performance testing of these devices utilized full-scale cranes and power line systems and a scale model facility. The evaluation results were reported in the Phase I report entitled "Evaluation of Proximity Warning Devices" dated 22 February 1980. Under the Phase II program, a microproressor-based data acquisition system was designed and developed to collect and measure field strength at distributed points around the crane boom. This unit (referred to as the Distributed Sensor AC Electrometer) measures the field strength about a crane boom using 17 distributed sensors. Keyboard control is provided for the equipment operator. Measured field strength values are displayed on a line printer and recorded on magnetic tape. Laboratory testing of this unit demonstrated performance characteristics and field strength measurement accuracy within the design goals. A Phase III measurements program is proposed using the AC Electrometer to map the field strength contours about power line configurations.

Jan 1, 1981

Conventional ferronickel smelting has five main steps: Drying, calcination, prereduction, smelting and refining. In the scope of the current work, smelting experiments were conducted using Sivrihisar laterite ores (1.26% Ni) of Turkey. The ore samples previously subjected to drying, calcination and prereduction stages were smelted in alumina crucibles in a laboratoryscale horizontal tube furnace under argon atmosphere. Smelting experiments were performed at 1500, 1550 and 1600 oC. The amount of excess coal used in prereduction step was another variable. Sivrihisar laterite ore is a limonitic one with low MgO composition. Therefore, MgO was added to the smelting charge as a flux. The effects of experimental variables on metal Ni content and slag composition were investigated.

Jan 1, 2012

By Adam H. Zimmerman

Introduction Noranda, like similar businesses, is suffering the pain of previously unheard of currency relationships, a cost structure built in better days, and conditions of gross oversupply possible in almost any commodity. Indeed, it does seem like the worst of all possible worlds is out there before us. To understand a Canadian natural resource company, you must know how the country is organized. So far as natural resources are concerned, Canada is not Canada. Canada is 10 provinces and each own the resources situated therein. Thus, the conditions of extraction, exploitation, and operation are all set by the province, while the conditions of trade and currency are set by the Federal government. This means that what may be the rule in Newfoundland may not be the rule in Manitoba or British Columbia. The second thing is that the Canadian currency has been a satellite of the US dollar for a long time. This means that we hold the unenviable and unjustified position of being the country with the second strongest currency in the world. What this has meant to us is what it has meant to an American operator. Since 1980, a pound of copper fetches 214% more for a Chilean than it does for us and a pound of zinc 115% more for a Belgian. From an American point of view, Canada is favored because its dollar is valued at 25% to 30% less than the U.S. However, because of industrial indiscretions in years past, Canada has a locked in labor cost disadvantage that is very hard to cope with. Canada has a unique situation with its labor unions. Many of the unions are, or have been, internationals and therefore gained undue strength in early days. Canada has a third political party of socialist persuasion. It is entirely funded by dues from laor union members. Thus, we have a politicized workforce. And finally, we have a public service that has the right to strike. This had made the public service unions by far the strongest now in Canada. What this means to the mining industry is that there is somebody out there blazing the trail. The unrelenting power of these public service unions probably creates a climate more conducive to excessive wage settlements in industry than would otherwise be the case. Study, Work, and Pray So what do we do when times get tough? In simple terms, we study a lot, we work harder, and we pray a great deal. We study a lot in terms of learning hitherto unknown strengths and weaknesses of our products, processes, and operations. We work hard in the sense that we do everything possible to improve our productivity. And we pray a lot because, so far, anything else we have done has not been enough. Some years ago, Noranda recognized that its principal base and precious metal operations were diminishing. To provide for the future, we should branch out into other resource type operations. These might be countercyclical and also perhaps a little more permanent. For this reason, Noranda entered the potash, aluminum, and forest products businesses. This, of course, was a 'brilliant' strategy that was much applauded in its early days. We built an excellent potash mine, the smallest inte-

Jan 6, 1985

The wealth of a nation may be measured in many ways, but one of the most important is its natural resources, particularly its minerals. Minerals create the wealth upon which economic prosperity and defense preparedness rest. Managing mineral resources for the benefit of all Americans continues to be an important national goal. In its 78-year history the U.S. Bureau of Mines has established itself as the world's premier mineral information and research agency. Its authoritative, comprehensive data and pioneering research have contributed significantly to a strong U. S. mineral position in the world.

Jan 1, 1988

By Donald O. Capstick

A mineral survey of the approximately 144,000-acre Borah Peak study area was conducted by the U.S. Bureau of Mines in 1985 at the request of the U.S. Forest Service. The area studied included the Borah Peak RARE II roadless areas (No. 14210, 119,864 acres of land recommended for wilderness designation; and No. X4210, 18,440 acres of land recommended as non-wilderness) and other contiguous Forest Service administered land. The study area is in Challis National Forest in southeast Idaho about 30 miles south-southeast of Challis, ID. Burnt Creek, a conterminous study area to the northeast, on lands administered by the U.S. Bureau of Land Managment, was examined concurrently. Dolomite and limestone inferred reserve bases exceed 1 billion tons each within the Borah Peak study area. The material is widespread and of high quality. Extensive sampling and more detailed mapping are required to better define the resources; however, ample dolomite and limestone occur nearby, outside the study area. Dolomite is the main constituent of several geologic formations within the study area. Sample analyses indicate that the more than 1,000-ft-thick Jefferson Formation dolomite is the most pure and is equivalent to material being mined at a dolomite-to-magnesium processing plant near Addy, WA. Analyses from limestone-bearing formations underlying much of the study area indicate that large quantities of the limestone may be suitable for a variety of uses.

Jan 1, 1987

By J. Vance Batty

The Permian Red Bed copper deposits of the South Central States are a potentially important resource. Only the higher grade, near-surface ores are now exploited because conventional froth flotation does not recover oxidized copper minerals which comprise 10 to 15 percent or more of the copper content of typical ore. Laboratory-scale beneficiation studies were initiated to devise a method capable of recovering both sulfide and oxidized copper mineral. Testing established that the high clay and gypsum content of typical ore prevented effective flotation of the oxide mineral using sulfidizing, fatty-acid, or oil emulsion techniques. A modified leach-precipitation-flotation (L-P-F) procedure recovered over 90 percent of the copper, compared to a recovery of 77 percent obtained by conventional sulfide flotation. The higher costs of the L-P-F method would reduce the increased revenue from higher copper recovery. An increase in copper price and/or an increase in oxide copper content of the ore would make the L-P-F process comparatively more attractive.

Jan 1, 1970

? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 2002

By T. Bertke

This document assesses the environmental aspects of a preliminary design for processing kaolin clay as the domestic resource for recovery of alumina by a hydrochloric acid leach-HCl gas induced crystallization process. The report covers waste sources, control measures, and potential environmental and health effects applicable to the process technology.

Jan 1, 1980

By D. J. MacDonald

Wettability measurements and laboratory waterflood tests were compared under a wide variety of conditions. Experiments were conducted with synthetic and natural crude oils, treated and untreated outcrop and oilfield sandstone cores, and synthetic brines with and without caustic, detergent, or phosphate additives. Measurements were made on equilibrated and unequilibrated systems at 77° and 150° F. Wettability was evaluated by the Bureau of Mines method from capillary pressure curves determined with a centrifuge. The waterflood data were fitted by empirical curves; the parameters of the curves characterize primary and subordinate production and also give the ultimate oil recovery. Results showed that wettability measurements at 77° F were useful predictors of recovery efficiency in waterflood tests run at both temperatures. Oil recovery in the early stages of waterflooding increased with increasing water wettability; however, the ultimate recovery was highest at a slightly oil-wet condition. The oil displaced at highest speed in the centrifuge was correlated with ultimate recovery in waterflood tests. Chemical additives to the brine sometimes lowered wettability and also sometimes improved waterflood recovery, but wettability and recovery were not correlated with additives present. The effect of additives on recovery in waterflooding was best seen in water-oil ratio curves.

Jan 1, 1974

By R. A. Vik

The influence of thermal treatments on the grindability of low-grade hematitic iron ores from Michigan and Minnesota was examined in bench-scale tests. Treatment factors were roasting temperature, roasting atmosphere, and ore cooling conditions. Bond ball mill grindability and work indices were used as response indicators in evaluating the condition of the ore. Of the three treatment factors evaluated, roasting atmosphere, which brought about the con version of iron oxides to magnetite, had the most significant effect; roasting temperature had the next most important effect; and cooling condition had the least effect. Optimum grindability was obtained with reduced-quenched products of both ores at 650° C, near the alpha-beta phase transformation of quartz.

Jan 1, 1971

By B Miles, D J. Williams, J Ahn, T A. Vangsness

The flooding of open strip coal mines in the Bowen Basin and Hunter Valley Coalfields of Eastern Australia has the potential to soften the spoil and floor materials to produce “mud”. This mud can act as a slip plane or weak zone when spoil is dumped into it, resulting in geotechnical instabilities. It is therefore important to understand the mechanisms and degree of degradation likely to occur within coal mine spoil of different qualities.To investigate this, five clay mineral-rich coal mine spoil samples were collected from the Bowen Basin, and each sample was subjected to wetting and drying cycles to simulate degradation that could be expected on wetting-up in situ, with their particle size distribution analysed both before and after degradation. These results were compared with the results of a modified slake durability test, in which the entire sample was tested.The paper presents the results of the accelerated degradation and modified slake durability tests on each of the five spoil samples. These results were related to the physical and geochemical characteristics of the samples, which highlighted their importance. The modified slake durability test may be used to rapidly simulate the expected in situ degradation of coal mine spoil on wetting-up, enabling susceptible spoil materials to readily be identified.CITATION:Vangsness, T A, Williams, D J, Ahn, J and Miles, B, 2018. Accelerated degradation and modified slake durability testing of clay mineral-rich coal mine spoil, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 83–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Brianna M. Eiter, Jennica L. Bellanca

Mineworkers face a challenging and dynamic work environment every workday. To maintain a safe workplace, mineworkers must be able to recognize worksite hazards while they perform their jobs. Though hazard recognition is a critical skill, recent research from the National Institute for Occupational Safety and Health (NIOSH) indicates that mineworkers fail to identify a significant number of hazards. To further the understanding of mineworkers’ hazard recognition ability and to begin to address hazard recognition performance, NIOSH researchers analyzed data collected during a laboratory research study to determine the effect of individual mineworker factors including risk attitude, work experience, and safety training on hazard recognition accuracy. The results of this study show that mineworker risk attitude and safety-specific work experience affect hazard recognition performance while hazard-specific safety training does not. These results suggest that some of these individual factors can be overcome through experience and training. Potential strategies that can be used to address these factors are also discussed.

Aug 31, 2020

By C. L. Schneider, C. O. Gomes, R. P. King, J. A. Finch, D. Lin

Discussion is presented by Prof. King and Dr. Schneider of the paper by Lin, Gomez and Finch published in Trans.IMM C, vol.104, 1995, p.C155-C161. They conclude that the correction procedures used for simulated observations of simulated capped spheres are not reliable when applied to mineralogical data and that their relative ranking should not be extrapolated to other situations. Properly regularised solutions obtained with the use of appropriate kernels can be safely used for routine mineral liberation work and can be calibrated accurately against real mineralogical samples in the laboratory

Jun 19, 1905

By Y. Y. Jiao, J. G. Cai

To investigate the dimensional effect on shock wave propagation in jointed rock masses, a 2-D and a 3-D calculation of a site test are performed respectively by using Discrete Element Method, the simulated results are compared with test data. It shows that, in modelling shock wave propagation and attenuation in jointed rock masses, when the explosive along explosion chamber is long enough and the joints are dense enough or uniformly distributed, the model can be considered as plane-strain problem, 2-D results are good enough to fit with test data. 2-D modelling, with much more details of rock masses taken into account, can be applied to make critical engineering judgements instead of 3-D modelling in some cases.

Jan 1, 2003