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By George A. Morgan

Output of mineral products was estimated to be unchanged in 1983 from that of 1982 with the exception of petroleum. The country began production of crude oil from the Seme Oilfield, and all output was exported. Wd and charcoal constituted 72% of Benin's total energy consumption, and imported petroleum products and electric power accounted for the remainder. Cement was produced from imported clinker. The gross domestic product (GDP) was $1,061 million in 1982, the latest year for which information was available.2 COMMODITY REVIEW Gold.-Exploration was underway at Perma by the U.S.S.R. as part of the United Nations development program. Gold had been produced previously at Perma, where a grade of 0.289 troy ounce of gold per ton was reported, An exploitation program for the deposit was to employ about 100 people, and output was targeted to reach 1,600 troy ounces per year. Recoverable reserves were put at 96,000 troy ounces.

Jan 1, 1985

By Kent W. Hawley

An improved visibility system was developed for use on the large (100 ton+) haulage trucks typically operated in open pit and surface mines. The improved visibility system provides the truck driver' with a means of viewing hazardous situations that occur in the extensive blind areas adjacent to his true. The cost effective, reliable, visibility system consists of a closed-circuit television three unique fresnel viewers, and two improved mirrors. This report describes the visibility problems of Large trucks in the surface mining environment, shows the performance of existing mirrors, substantiates concept selection, and describes the prototype improved visibility system.

Jan 1, 1978

By Peter de Bakker

The objective of this contract was to develop a simple, reliable, economical, remote-control roof bolting module for installation of mechanical and resin bolts. It was to be capable of placing longer than seam height bolts, up to 10 ft lengths, from a seam height of 36 to 72 in., while keeping the operator under supported roof. The resulting machine, called REM-Bolter, is a low profile unit that utilizes Foster-Miller Flexible Shaft Roof Drill, a Bendix Roof Bolt Inserter and a newly designed. Roof Bolt Lifter/Torquer. Every effort was made to strike a compromise between complete automation and complete manual control. In a controlled laboratory environment the REM-Bolter remotely installed 1000 bolts. Subsequently the machine was tested in an operating coal mine where 500 holes were drilled (and an equal number of bolts were installed) remotely, over a 4 month period. The results of all tests Live shown that the operator of a machine of this kind can quickly, and repeatedly, install rootbolts remotely from his operator compartment some 8 ft away from the drilling/bolting action. The report includes recommendations for improvements to the present REM-Bolter design that would translate the present test bed into a second generation test bed and a potential first generation production unit.

Jan 1, 1983

By Ray E. Harris

Introduction A resource of more than 122 Gt (134 billion st) of minable trona and mixed trona and halite underlies an area of about 3400 km2 (1300 sq miles) west of Green River, WY (Culbertson, in preparation) (Fig. 1). In 1982, the total domestic consumption of soda ash (refined trona) was 6 Mt (6.7 million st) (Kostick, 1983). About 90% of this came from Wyoming trona. This enormous deposit occurs in the Wilkins Peak Member of the Green River Formation that is of Eocene age. This formation is derived from sediments deposited in a large lake named Gosiute. Lake Gosiute occupied the Green River Basin in southwestern Wyoming some 38 to 54 million years ago. The Wilkins Peak Member represents a restricted, evaporite-rich cycle of deposition when the trona deposits were formed. A total of 42 trona beds are known. Of these, 25 are of sufficient thickness and extent to be considered minable (Culbertson, in preparation). The production of sodium compounds from the trona deposits in the Wilkins Peak Member began in 1896 when wells were drilled within the present boundaries of the town of Green River. The purpose of the drilling was for extraction of sodium carbonate brines. Sodium carbonate (sal soda) was removed from these brines at a plant in Green River. Bedded trona was discovered in 1938 in a core from an oil well drilled south of Westvaco. In 1947, the underground mining of trona began. Production has continued from 1948 to date. Currently, five companies are mining trona and producing soda ash from the Wilkins Peak Member in Wyoming. Additionally, Allied Chemical Co. mines and processes trona for Church and Dwight's sodium bicarbonate (baking soda) operation in Green River. Competition in the soda ash industry depends primarily on the efficiency of mining and refining, allowing for lower-cost production. Newer plants and mine designs should increase efficiency. Solution mining holds promise as an even lower-cost method of mining. Employment in the soda ash industry is declining since the newer mining and refining methods are less labor intensive. Declines in employment, however, may be offset as production increases. Due to the large resource, the availability of minable trona should not be a problem for perhaps hundreds of years. Geology of Wyoming trona deposits Forty-two beds of trona or mixed trona and halite occur in the

Jan 10, 1985

By Mandeep Singh

The smelting of lead ores has been carried out in southeast Missouri for centuries, and modern smelting practices have generated a variety of waste products. Lead blast furnace slag is one such product, which typically contains 10% zinc, 25% iron and 2% lead. This slag has often been stockpiled on the producing smelter site and accumulations have now reached several million tonnes. It is possible that in the near future these slags will be classified by the federal Environmental Protection Agency as hazardous, and therefore there is considerable interest in possible treatment processes to render the slags non-hazardous by removing the offending metallic elements. To ensure that the overall slag processing costs are kept to a minimum, it is imperative that lead and zinc be recovered in a form suitable for sale or further processing. There are two generic routes for processing blast furnace slags and they involve hydro-metallurgical or pyrometallurgical techniques. With hydrometallurgy, the slags would be leached directly and the metal values recovered from purified leach solution(s) by electrowinning. One problem with processes of this type is that the zinc and lead grades of the slags are low and the iron content is high, and thus the economics of metal production are often not favorable. For pyrometallurgical processing (1), it has been shown that the slags can be fumed to produce an oxide dust containing all the lead and zinc, and representing only a fraction of the weight of the initial slag. The oxide dust may then be processed hydrometallurgical to recover zinc and lead.

Jan 1, 1992

By Jean-Marie Fecteau

The gold mine sector is presently facing low gold prices as well as technological challenges. Its competitiveness and survival will depend on new mining methods and equipment to improve ore extraction. In 1999, Natural Resources Canada has invested new funds over a period of three years at CANMET?s Experimental Mine to establish the Narrow-Vein Mining Project. A team of engineers and researchers specialised in mining, mechanics and electronics engineering are working to meet the critical need of ore-extraction technology. CANMET?s program in mechanisation and automation for narrow vein mining had, prior to 1999, realised several important achievements, many in co-operation with a consortium of mining companies (Soredem). The investment of new funds in this area will contribute to develop technologies to improve the productivity, as well as health and safety conditions of the narrow vein mining industry. Several important impacts of this project will be monitored. Specifically, a database of methods and equipment used in narrow vein mining is being developed. A key thrust is to identify operators? needs with respect to the development and automation of mining methods and equipment. Based on those needs, research and development projects will be created. The main problems identified following meetings with mine operators are described with a few elements of solution and the Web site created for the broadcast of the results is presented.

Oct 1, 2001

By Jim Wickens, Vince Lofftus, Mark Kravetz

"This paper discusses how Bald Mountain Gold Mine (Ely, NV) dramatically reduced mercury production by treating process solutions with a liquid reagent based on organic sulfide chemistry. Cherokee Chemical Co. Inc. (Vernon, CA) markets this reagent as UNR 81 1A.A summary of the bench tests comparing various reagents is given. The ensuing plant trial is discussed and successful mercury removal results are presented. Data is presented to show that early removal of mercury in the process reduces the amount of mercury collected at retort. Data is also presented to show that use of this reagent does not reduce gold recovery. Plant trial treatment costs are discussed. Finally, the potential of this technology to substantially reduce closure costs as compared to traditional mercury removal options is discussed.INTRODUCTIONBald Mountain Mine produces gold. Mercury is a costly by-product of gold production because no revenue is generated from mercury. Traditionally, mercury leaches out with gold and follows the gold throughout the processing circuit until it is eventually condensed and collected at Retort. Minimizing or eliminating mercury production minimizes worker health and safety risks, minimizes environmental liability, and reduces costs. In the long term, minimizing mercury production will make mine closure easier and less costly.Bald Mountain Mine dramatically reduced mercury production by treating process solutions with liquid reagents called UNR 811 and UNR 811A. Several reagents were bench tested before proceeding with a plant trial. The reagent complexes the mercury to form an insoluble organic sulfide precipitate. In independent tests, the precipitate passed acid mobilization tests and is considered stable."

Jan 1, 2001

By Dale Bartholomae, David Harrison, Edward J. Walter

Methods that involve the use of signature blast holes in order to identify the particular frequency characteristics of a geographical area are widely available. Information acquired can be used to determine optimum blast hole timings to produce the desired constructive and destructive inference. However, these types of analyses can be both complicated and expensive. This study will investigate the use and practicality of signature hole and/or shift and sum analysis software and their application to small diameter construction utility blasting operations in Pennsylvania and faster moving projects in general. A determination will then be made as to whether this technology can be utilized by today’s blaster, from both a functional and a cost effective basis. Single hole blasts will be detonated on various smaller construction projects and will be monitored with an array of seismographs. The collected data will be analyzed in order to determine the optimum timing between holes to produce the preferred frequency content while keeping in mind the explosives user’s current inventory of blasting supplies.

Jan 1, 2005

By F. S. A. de Frey

The author would like to refer to his contribution to the paper `Design of pillar systems in South Africa' by Ozbay et al. 1. The authors agreed `wholeheartedly that further research, together with carefully planned field trials, in pursuit of this potentially highly rewarding concept' of the small span small pillar method is warranted. On 30 September 2010 the author went underground at the Kroondal Chrome Mine to observe how the concept of smaller spans was being applied. He was pleasantly surprised to find that the typical coal mine bord and pillar sytem was being used very successfully. Although the deepest mining was taking place at a depth of only 450 metres, Kroondal would be an ideal mine to do further research together with carefully planned field trials. At Crown Mines Gold Mine, where the author worked, he was informed that the first recorded rockburst took place at a depth of 635 metres below surface. The depth of the platinum and chrome mines is increasing, with the risk of an excalation in injuries and fatalities due to 'backbreaks' and siesmic activity. The rock engineer at Kroondal was not aware of backbreaks occuring on the mine. It is important that the rock engineers of the base mineral and gold mines get together and give more serious attention to the host rock environment in which the pillars are situated.

Jan 1, 2011

By L. A. Cornish, S. N. Prins, R. Süss

The work is being done using the Thermo-CalcTM software, and the database is being built up by obtaining good thermodynamic descriptions of all of the possible phases in the system. The database supplied did not cover all of the phases, and these had to be gleaned from literature, or modelled using experimental data. Similarly, not all of the experimental data were known, and where there were gaps or inconsistencies, experiments had to be undertaken. A preliminary version of the database was constructed from assessed thermodynamic data-sets for the binary systems only. The binary descriptions were combined allowing extrapolation into the ternary systems, and experimental phase equilibrium data were compared with calculated results. Very good agreement was obtained for the Pt-Al-Ru and Pt-Cr-Ru systems, which was encouraging and confirmed that the higher-order systems could be calculated from the binary systems with confidence. Since some of the phase models in databases were different, these phases had to be remodelled. However, more work is ongoing for information concerning the ternary phases present in the Al-Cr-Ru, Pt-Al-Ru (two ternary compounds in each) and Pt-Al-Cr (possibly more than three ternary compounds) systems. At later stage of the work, problems with the thermodynamic descriptions of the Cr-Ru and Pt-Cr binary systems were found. A programme of experimental work to overcome these has been devised, and is being undertaken. Keywords: Pt-based alloys, phase diagram calculations.

Jan 1, 2006

By S. O?Connor

When one looks back and does assessments of what has been the key ingredient in achieving success in our safety efforts, there are many issues that spring to mind and cover a wide array of elements. One does not know which has the ultimate maximum effect. In his presentation yesterday, Alan Peers, our SHEQ leader, covered a lot of detail with the way we are managing safety at Modikwa. I have attempted to identify some of the key essentials in making the mine safe. Passion Safety is addressed with a passion that is unbelievable at times. When I get phoned because an incident has occurred and in reporting the incident, there are already action plans being put in place to prevent re-occurrences, you understand the commitment to put employees? safety first. You hear the disappointment in your subordinates? voices when they have to share the fact that an incident or accident has occurred.

Jan 1, 2011

By R. L. Pienaar

Paper written on project work carried out in partial fulfilment of B Eng (Min. Eng.) degree A study was conducted to investigated and compare the feasibility of two single level extraction layouts for an intact part of theorebody of the De Beers diamond mine, Koffiefontein. Two layouts were chosen and the tonnage profile, development schedule and production ring blast layouts were calculated by applying the information acquired through a literature study. Current principles used on the mine were also applied. The first layout chosen is described as a simple straightforward layout with 6 production tunnels spaced 15 m apart, and is referred to as Layout A. The second layout, named Layout B, is described as a complex chevron layout with 9 production tunnels spaced 15 m apart. This layout has a rim tunnel situated in the kimberlite ground, which is called a chevron and this made the layout more complex than Layout A. By comparing the financial results of the two layouts, it was found that Layout B is a more feasible option than Layout A. Sensitivity analyses show that both layouts are extremely sensitive to the revenue of the projects. Therefore it is recommended that Layout B can prove to be a source of additional tonnage to add to the total tonnage profile of the mine and to extend the life of mine by 20 months, only if certain financial/economic factors improve. There is, however, still some areas of the project that need to be investigated.

Jan 1, 2006

By M. Javier

Mining is an industry of experimentation throughout human history. Recently, societies are giving a clear message about mining because many projects are being rejected around the world. These refusals are a generational reaction to the activity of mining. In practice, it generates the perception that mining is using the same methodology without attending to the gradual initiation of conflicts. This is in spite of the best engineering and technology of the time that are put in place at the presentation of those mining projects. Some of these rejected projects are geographically distant from each other, but the communities? rejection occurred during many cases under similar characteristics. This concern shows that the current model of mining projects needs to be replaced with a new one: A new Design, one within which the socio-environmental values of this millennium are inherent. This paper describes Mining Project 101 to help the industry to set the highest and cleanest standards for mining. It also presents its aspects to sustainability and nature, which provides the principles and procedures for designing, planning, and operating mining projects with sensitivity to nature. It offers methods of diagnostic, remediation, and extraction while at the same time preventing and preserving a physical, chemical, and biological equilibrium of nature. This emerging process will be a step up from having a mining industry unaccountable to the socio-environmental conflicts it perpetrates and will abandon the ?cosmetic? repair on the caducity of traditional models in today?s practice. In conclusion, we have the opportunity to change this model. KEYWORDS: Equilibrium in Nature, Geomímic, Deproduction, mine design.

Feb 27, 2013

By J. G. Henning

Following completion of planned mining operations at the Goldcorp Dome Open Pit Mine, a high-grade Shaft Pillar located in the pit highwall was recovered. Mining of this Shaft pillar faced numerous rock engineering design and implementation challenges due to its remote position on the highwall and the presence of mine workings within the wall. The case example presented in this paper discusses the geotechnical investigation performed at the site, novel measures undertaken for installation of ground support required for rockmass reinforcement and for worker protection, as well as operational challenges to successful mining of the Shaft Pillar.

May 1, 2009

By J. M. Ekenes

New approaches that increase hydrometallurgical recovery from refractory minerals in below-mill-cut-off-grade sulfide copper ore can add significant value, improve profitability and increase ore reserves. This paper describes the development and implementation of an engineered heap (EH) approach to leaching low-grade, chalcopyrite-bearing ore at Freeport-McMoRan?s mine in Morenci, Arizona. The technical evolution of the engineered heap concept is described together with the challenges and benefits following implementation.

Jan 1, 2012

By Joseph Grumer

An instrumented spherical vessel has been used for many years to study laminar combustion waves. Concurrent measurements of flame speed and pressure-rise rates have led to evaluations of burning velocities, the pressure dependence of the burning velocity, and the expansion ratios of the gases passing through the combustion wave. For the most part, these studies have involved flames initially at atmospheric or subatmospheric pressure. The old spherical vessel used by the Bureau of Mines was not designed for use at elevated pressures. Moreover, being made of wrought iron, it was susceptible enough to corrosion to prohibit its use with many combustible mixtures that figure in industrial research. In mid-1956, under sponsorship of the Office of Naval Research, the Bureau undertook the development of a stainless steel spherical vessel capable of withstanding explosions of gaseous mixtures at initial pressures as high as 20 atm. and initial temperatures as high as 250° C. The design called for a double array (cross) of closely spaced small windows for observation of the flame as it traversed the vessel and a piezoelectric transducer to measure concurrently pressure-rise rates. Because no commercial contractor was willing to bid on the construction of such a vessel, it was built at the Bureau's Bruceton machine shop.7

Jan 1, 1961

By Charles Findlay

As one of its projects for degasification of major panels of coal prior to mining within them, the Bureau of Mines conducted methane emission studies during development of a set of three headings 1,800 feet in a major coal panel (2,700 by 3,500 feet) which had been completely isolated by sets of main headings for 12 months in the Federal No. 2 mine (Pittsburgh coalbed) in northern West Virginia. Similar emission studies were conducted in the development of two sets of main headings in virgin coal areas nearby. Comparing the two sets of data indicated that the isolated coal panel had been degasified by approximately 70 percent.

Jan 1, 1973

By Bill Cain, David F. Tsztoo, R. John Caulfield, D. Scott Kieffer

In 1994, the East Bay Municipal Utility District (EBMUD) commenced a system-wide Seismic Improvement Program to protect their facilities from catastrophic damage. A primary focus of this program has been on retrofitting the 75-year old Claremont Tunnel, which crosses the active Hayward Fault zone. A large earthquake on the Hayward Fault could generate enough right-lateral fault slip to effectively sever this important lifeline. The retrofit project involves construction of a new bypass tunnel through the Hayward Fault zone, together with systematic contact grouting and localized structural repair of the existing concrete liner. Several innovative design measures have been incorporated into the seismic retrofit design, including an oversized tunnel cross section, backfill concrete side drifts, seismic isolation of an internal structural pipe, and shear fuses in the final lining.

Jan 1, 2005

By Dan L'Heureux, Joe Haid, Stephen H. Chung

Most coal deposits in Western Canada involve steeply dipping multiple seams. An efficient way to recover coal seams would be to drill through the seams and blast both the overlying and underlying waste material in one shot without disrupting the coal seams while fragmenting the waste rock for easy removal. This requires special blasting techniques as reported by Chung and Jorgenson in 1985.

Jan 1, 1998

Pese a tener cajas sólidas en su estructura, algunas vetas desarrollan un relleno frágil, ocasionando problemas futuros de sostenimiento para el "corte y relleno" de los mismos. Por ello, se utilizó el método de los "Square Sets", donde además de ser costoso, implicaba eliminar una proporción de la roca encajonante y diluía el contenido metálico de los filones. En ese sentido, el objetivo del texto es señalar la viabilidad del "método Cornish"como método alternativo, económico, de rendimiento óptimo y que no presenta riesgos para el personal o la labor realizada. Este método es aplicable en aquellas vetas uniformes no falladas, que tengan desde una potencia pequeña hasta aquella que sea posible apuntalar, así como en aquellas que requieran sostenimiento del techo en la veta mima o donde se realizen Shrinkages. El proceso del método se basa en la preparación de los tajeos, luego en la explotación(perforación y disparos), enmaderado, relleno del tajeo, recuperación de madera, las variantes en la preparación del tajeo y la recuperación del mineral. La única desventaja que ofrece este método es su peligrosidad, dado que si se aplica en zonas inadecuadas o sin la supervisión que garantice el cumplimiento de las normas preventivas, es preferible el uso de los "Square Sets". Sin embargo, la aplicación del método resulta mucho más productiva en rendimiento teórico puesto que alcanza de 7 a 10 toneladas por tarea de 8 horas y responde satisfactoriamente siempre y cuando las condiciones de las vetas lo permita.

Jul 20, 1957