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By K. Duckworth

"AbstractA new electromagnetic depth sounding technique was applied to the measurement of salt thickness above the workings in the Central Canada Potash Mine at Colonsay, Saskatchewan. The initial tests indicate that this new technique can measure salt thickness and that the technique possesses operational feature s which make it possible to monitor trends in salt thickness throughout the mine. The technique can be applied using existing equipment, but the tests do indicate the desirability of developing equipment with features specially suited to the mine environment.IntroductionTESTS were conducted in the Central Canada Potash Mine at Colonsay, Saskatchewan during 1974 and 1975 to determine if a new technique in electromagnetic depth sounding could provide a convenient means of measuring salt thickness above the workings. This new technique, which was described by Duckworth (1975), offers operational features which appear to be advantageous in this particular situation.The problem requires that soundings be made upward from the mine workings to the base of the second red shale. This shale forms an impermeable seal on top of the Prairie Evaporite. A knowledge of this salt thickness is of interest due to the need to avoid any possibility of the workings rising to cut the red shale. Another desirable objective is the detection of any disruptions of the red shale. Ideally, this should be done ahead of the workings in order that such areas of disruption may be avoided."

Jan 1, 1977

By Louise Reber

THE town of Jerome is located in Yavapai County in north central Arizona. It has a population of over 6000 people and the two important mines of the district, the United Verde and the United Verde Extension, lie almost within its limits. Perched high on the southwest side of the Verde Valley, at elevations of 4800 and 5500 ft.. (1463 and 1676 m.), both mines have long tunnels from their lower levels through which ore is hauled to their respective smelters. The two smelter towns of Clarkdale and Verde, out in. the center of the valley and about 2000 ft. (609 m.) below, form part of the wide panorama that meets the eye at Jerome. This panorama and the topographic and surface features and the geologic formations are shown in a separate pamphlet. In the vicinity of Jerome, the great southern escarpment of the Arizona plateau forms the northeast side of the Verde valley. The general level of this escarpment, or "the rim" as it is called, is about 4000 ft. above the Verde River. A corresponding elevation is reached only by the, highest parts of the Black Hills, which bound the valley to the southwest. The two lava-capped mesas, known as Mingus and Woodschute Mountains, form the culmination of the Black Hills. That part of the old Black Hills mining district which lies between their crests -and the Verde River is now known as the Jerome or Verde copper district. However, if the smelters are not included, a strip about 7 mi. long and 3 mi. wide (11 by 5 km.) embraces practically all the properties belonging to the Jerome district. This strip lies parallel to and along the side of the Verde valley from about First View, 2 mi. northwest of Jerome, to the neighborhood of Allen Spring, near the south end of Mingus. Mountain. The rank of the district in copper production, as well as features of peculiar geologic interest in connection with the ore occurrences, entitle the district to much more consideration than it has received in the literature of copper mining. Arizona stands preeminent as a copper-producing state. In 1918, it produced four-tenths of the total amount produced in the United States, and nearly equaled the, combined production of its three chief competitors, Montana, Michigan, and Utah. The production of the Jerome district places it in the sixth place among the copper

Jan 8, 1920

By James G. McKelvey

Owners have seen several major tunnel projects in recent years fall victim to a general reduction in the number of bidders as well as an erratic range of pricing. It should be noted though that this is not a universal trend and some projects have seen good competitive bids. Contractual terms and conditions are an important factor in attracting good competition. The Front End documents of tunnel projects have come under increasing scrutiny as tunneling contractors in the U.S. industry are looking much more closely at their risk exposure in the contract terms and conditions. Considering the amount of tunnel construction work upcoming in North America, it is important that General and Special Conditions are put together in a way that provides a reasonable basis to execute the Contract and also provide a fair, balanced and swift way to resolve disputes.

Jan 1, 2008

Water Balancing in Mineral Processing - Issues and Opportunities

Sep 13, 2010

By M. Nete

Qualitative analysis of three mineral samples from northern Mozambique was accomplished by X-ray diffraction (XRD), microscopy, scintillation, and magnetic determination. Chemical characterization was accomplished using ICP-OES and pressed powder XRF after dissolution using microwave-assisted digestion and flux fusion. The samples consisted of a mixture of minerals with tantalite as the major component, with minor amounts of microlite, quartz, mica, accessory garnet, and tourmaline. Incomplete dissolution was obtained using microwave digestion, with maximum recoveries of 90.25 ± 0.06% and 88.90 ± 0.04% for Nb2O5 and Ta2O5 respectively. Complete dissolution using Li2B4O7 resulted in recoveries of 98.5 ±0.2% Nb2O5 and 100.4 ± 0.3% Ta2O5.

Jan 1, 2012

By Bali. D. D., S. Chattopadhyay

"The planning and construction of prime coking coal beneficiation plants in the nationalized mines in India are reviewed. Flow schemes, construction practice, materials consumption, and costs are detailed.Medium-capacity beneficiation plants with multiple loops are recommended under Indian conditions.IntroductionThe reserve of high-grade and easily washed metallurgical coal in India are quite limited. Prime coking coal constitutes approximately 22% of the total resources and occurs exclusively in the Jharia coalfield in the state of Bihar. Bharat Coking Coal Limited (a subsidiary of Coal India Limited (CIL) the nationalized mining sector of India) owns 80% of the Jharia collieries. The development of Jharia coalfield in the pre-nationalized period before 1971 has been characterized by a large number of small mines with primitive mining methods and low productivity. The production of prime coking coal to meet the demand of the steel industry in India has to increase from the existing level of 11.1 million tonnes to 43.4 million tonnes per annum by 2000 AD, thereby producing 5.61 million tonnes and 22.7 million tonnes of clean coal respectively. An ambitious program has been undertaken for development of bigger mines with an average production of 1 to 3 million tonnes per annum. With the fast dwindling reserves of good quality coking coal, more inferior grade coal seams, having difficult washing characteristics, are now being mined. All the coal from the future mines will have to be beneficiated to make it suitable for consumption of steel plants; the following washeries are being planned for construction by 2000 AD:"

Jan 1, 1986

By Mark A. Williams

"This paper was originally intended to be a presentation of a case study of two surface bituminouscoal mines in the southern Appalachian coal fields located within five miles of each other. These mines were nearly identical in every aspect from geologic setting to equipment application. Althoughrepresentatives from each mine desired to participate in the preparation of this paper through support in providing background information and in review and editing, it was later concluded that, due to the environmental sensitivity associated with each mine, it may not have been a good decision to present this case study in a public forum."

Jan 1, 1994

Study on Treatment of Wastewater Containing Heavy Metal Ions Using Modified Oceanic Cobalt-Rich Crusts

Sep 13, 2010

By J. H. East, R. S. Sanford, W. M. Traver, W. S. Wright

"INTRODUCTION This report describes the results obtained from a diamond-drill exploration project performed by the Bureau of Mines on the nickel deposits of the Yakobi Island, Alaska. The Federal Geological Survey 6/ completed a detailed geologic study and mapped the area during the summer of 1940, and a Bureau of Mines examining engineer 7/ made a preliminary examination of the deposits in June 1941, at which time core drilling was suggested as the logical means of determining the extent and grade of the deposits. Equipment and supplies were unloaded on the beach at Yakobi Island on October 21, 1941. The drills were moved to Bohemia Basin, where actual drilling operations wore begun under the direction of a Bureau of Mines engineer 8/ on November 7, 1941. Two core-drill holes were completed on December 7, 1941. Upon the request of the drilling contractor, operations were recessed owing to severe winter conditions. Work on the project was resumed April 27, 1942, under the direction of another Bureau of Mines engineer 9/ and was completed August 15, 1942. During the 1942 season, 13 core-drill holes were completed, and 10 surface pits and a tunnel were sampled. A total of 5, 191 feet of core-drill hole was drilled in 15 holes during the entire project. The results of drilling and sampling form the basis of this report."

Jan 1, 1948

By Dale Preece, Steven Sobolik, Richard Jensen

Recent events demonstrate that civil and government facilities and structures face an ever-increasing need to be designed for protection against malevolent explosions. Modification of existing public structures and especially design of new ones increasingly includes provisions for explosive protection. ISEE members endorse and promote responsible application of explosives to benefit mankind and deplore any other use. However, our knowledge of explosive behavior and our ability to predict the results of explosive events puts us in a unique position to give guidance to designers of civil and public structures. Recent advances in computational methods have resulted in new computer codes with ALE (arbitrary lagrangian eulerian) simulation capabilities. Historically, lagrangian computational methods have been used for modeling solids because the mesh or discretization moves with the material. Rock breakage resulting from explosively induced shock-waves has been successfully modeled with lagrangian codes. Explosive detonation has traditionally been modeled with eulerian techniques. Eulerian methods have been used to model gases and fluids, tracking the material as it moves through the computational grid. ALE computational technology couples the two methods together in a manner never before possible. An ALE simulation can accurately treat the explosive detonation, interaction of explosive gases with air, and the impact of explosive event on nearby solid structures. ALEGRA (Budge et al. 1997 a & b) is an ALE code developed at Sandia National Laboratories. ALEGRA simulations accurately predict the explosively induced impulse on the structure to be protected. It has been applied to the analysis and design of blastwalls to protect structures and people from explosive events. The impulse calculated can be used by structural engineers to design a blastwall. ALEGRA has also been applied to predict the effect of a blastwall on explosion overpressure some distance behind the blastwall to assess the effect on people present during the event.

Jan 1, 2000

By Nicholas Adrian Barcza

"What affects and influences one’s perspective of the mining and metallurgical industries?One’s perspective of the industry we work in changes over time as a function of our experience as well as from the interaction we have with colleagues locally and probably even more so with those internationally. Furthermore, the ever-changing environment continues to impact the context in which one sees things. Living mostly in South Africa through its changes in the past fi fty years but also having the opportunity to travel extensively and work on projects abroad adds an invaluable richness to this more global perspective. One of the greatest challenges is how best to use this experience to endeavour to support the many potential opportunities in southern as well as sub-Saharan Africa. However, one has also to face the realities of how the best interests of the country and its peoples are sadly often not well served for various unfortunate reasons. Investment, education, regional stability, and good governance are some of the most critical considerations for the prosperity and survival of the region.The mining and metallurgical industry in southern and sub-Saharan Africa changed significantly during the post-colonial and apartheid eras as a result of global and regional developments that have impacted the ownership of businesses, the technologies used, and products produced in a manner that was not envisaged even fi fty years ago. Southern Africa’s mining and metallurgical industry has progressed from one based mostly on diamonds and gold in the late 19th century to a much more diverse one that involves the production of a variety of other precious, base, and ferrous metals and minerals as well as coal and industrial minerals. The infrastructure and manufacturing capacity was largely developed to meet the needs of this industry during its growth phases, but even though the dynamics have changed there is still a need for more efficient and effective support systems in the region."

Jul 1, 2019

By L. R. Herrmann

The research described in this report is the first phase of a comprehensive program for the development of a characterization for the structural properties of rock masses. The mathematical expression of the characterization is especial' tailored for use in conjunction with modern structural analysis procedures. The objective of the first phase of the project is to determine the feasibility of representing the structural properties of rock masses in terms of the analysis of an appropriate "representative volume" the results of this investigation are described in detail in the body of the report. The current state-of-the-art concerning the understanding and description of the fundamental mechanisms of rock behavior are determined from a survey of existing literature. The development of a representative volume that captures the most important of these mechanisms is described, In order not to unduly obscure the fundamental aspects of this development, the mathematical analysis of the representative volume is limited to plane strain conditions. A subroutine for the numerical evaluation of the proposed model (i.e., the analysis of the representative volume) is presented. The steps necessary for the incorporation of the subroutine directly into existing two-dimensional finite element structural analysis programs are described. Comparisons between the predictions of the proposed characterization and published results of simple laboratory tests are presented and discussed. Finally recommendations are given concerning suggested improvements of the model and the extension of it to the general three-dimensional case.

Jan 1, 1974

By Albert Musschoot

The expanding applications of vibrating feeders for controlling the flow of bulk materials, and their adaptation for processing requirements, have developed considerable interest in stockpiling and reclaim systems. The general design of these units consists of a material transporting trough, or platform, driven by a vibratory force system. Design flexibility and variety is limited only by engineering ingenuity. The basic motion of the vibratory trough, or work member, is a controlled directional linear vibration that produces a material tossing or hopping action. Material travel speeds vary from 0 to about 30 m/min, depending on the combination of frequency, amplitude, and slope vibration angle.

Jan 6, 1981

Study on Mineral Processing of Refractory Copper-Nickel Ore

Sep 13, 2010

By S. S. Makgato

In this study, coke oven tar additions over a range of 0?8 wt.% were evaluated as a possible substitute for imported coal fractions. The coke oven tar used was collected from tar decanters in the byproducts section of the coking plant. The moisture content in the tar varied depending on the residence time and water carryover from the coke oven tar separators to the storage tanks. Moisture contents of 1 wt.%, 3 wt.%, and 6 wt.% were investigated in order to evaluate the effect on coal blend, carbonization, and coke properties. At 6 wt.% moisture content with 6 wt.% coke oven tar, although the coke quality improved the yield showed a 4% decrease. On the other hand, 1 wt.% moisture content with coke oven tar of 6 wt.%, increased the yield by 1% and the coke quality improved. However, the latter process was characterized by an excessive increase in wall pressure and pushing energy, both of which are detrimental to the oven walls. The optimum moisture content in coke oven tar was found to be 3 wt.% with a coke oven tar addition of 6 wt.% in the coal blend. With these conditions, the coke properties improved and wall pressure and pushing energy were acceptable. However, a decrease in coke yield of up to 2% was observed. Despite this, coke oven tar addition is considered to be a viable option based upon economic factors of a reduction in the quantity and cost of imported coking coals that is required to achieve the same optimum final coke product. Keywords coal substitution, coke oven tar, tar moisture, coal blend, coke, coke quality.

Nov 1, 2013

By J. Z. Cui

In this paper a statistical multi-scale method for the mechanics parameter prediction of the rock mass with random distribution of multi-scale cracks/joints is presented. First the micro-structure of the rock mass with random distribution of multi-scale cracks/joints is represented. Then the statistical second-order two-scale method for the mechanics performance predictions of the rock mass structure with random cracks/joints distribution is presented, including the statistical second-order two-scale expression on the vector-valued displacement, strain tensor and stress tensor, and the algorithm procedure of statistical multi-sale computation for the mechanics parameters. Finally some numerical results for mechanical parameters for the rock mass with random distributions of multi-scale joints/cracks by statistical multi-scale method are shown.

May 1, 2009

By W. A. Calhoun

A method for treating high-iron Arkansas bauxites for recovering both abrasive and metal-grade bauxite has been developed by the Bureau of Mines. Present practice usually produces a reject containing appreciable quantities of metal-grade bauxite; however, the processing renders the alumina in the reject unsuitable for the Bayer extraction treatment. Thus the Arkansas abrasive bauxite industry has, in the past, produced little or no metal-grade bauxite. The present investigation was made to determine the possibilities of batter utilization of those particular bauxites through recovery of the wasted metal-grade portion. The large expansion of aluminum-production facilities planned for 1951-53 makes recovery of metal-grade bauxite from presently treated abrasive and marginal abrasive ores en especially timely objective and a welcome addition to our aluminum potential. The quality of the Arkansas bauxites and the inherently associated titania content have made this material particularly attractive to the abrasives industry. however, the gradual depletion of natural abrasive-grade bauxite reserves in this area, the comparative scarcity of high-grade ore, and the difficulty of maintaining adequate reserves have necessitated blending different grades of bauxite calculated to meet specifications. Production of abrasive-grade bauxite from tile, high-iron reserves 13 becoming, increasingly necessary. In one commercial operation, producing abrasive-grade from ores averaging slightly less than 10 percent Fe2O3, approximately 2.7 tons of ore are required to produce 1 ton of abrasive-grade bauxite. The reserves of ore of this grade, however, have been considered inadequate for a long-range production, and ultimately ores averaging 12 to 15 percent Fe2O3 will have to be treated to moot the continued demands of the abrasive industry.

Jan 1, 1952

By Randy Wheeler

One of the more difficult topics to address concerns the effects of vibration on historic structures. Not only blast induced vibration, but also vibration from other transient and semi-continuous sources like, traffic, human activity, and environment forces. A common question might be, “What level of blast-re l a ted PPV is considered safe?” A review of some of the papers available from the ISEE Explosives Reference Database on CD ROM shows that 0.50 inch per second was often used. It was not clear on what basis this value was selected except that it represents the low frequency limit for plaster developed by the United States Bureau of Mines in RI 8507. In another case, a limit of 0.20 inch per second was mentioned, apparently simply because it was ten times less than 2.00 inches per second.

Jan 1, 2004

According to the data provided by the most recent European Survey on Working Conditions, roughly 25 per cent of the European working population is exposed to mechanical vibrations for no less than one quarter of the work shift duration, while around ten per cent are exposed for the entire work shift. The occupational exposure to whole-body vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European Directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacturer). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace; actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253.

Dec 6, 2010

By James W. Harrower, Gerald S. Ball

This paper discusses the installation of steel linings in vertical, raisebored openings. Design criteria used to evaluate the applicability of liner type and design are presented as well as a brief description of installation procedures. Specific projects completed by J. S. Redpath Corporation are then outlined noting special considerations and techniques.

Jan 1, 1985