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By John K. Irwin

Friction hoisting has assumed a major role since its introduction to North America less than ten years ago. Interest was illustrated by a recent visit of the Adirondack Section of AIME to a new friction hoist at Chateaugay mine of Republic Steel Corp. at Lyon Mountain, N. Y. The 80-in. diam, 4-rope machine at Lyon Mountain is typical of modern friction hoists. The hoist is mounted on a structural steel tower without deflection sheaves.

Jan 10, 1963

By D. J. Cox, J. P. Conway, A. E. Gooch

A two-year test conducted by the USBM's Spokane Mining Research Center (SMRC) has proven the feasibility of the yielding rockbolt, a concept which may prove very useful to the mining industry by providing ground support under a variety of conditions. The yielding rockbolt was originally developed in South Africa3 to overcome the limitations of conventional bolting in rock subjected to high-stress or rock burst conditions. The yielding effect is obtained by fitting the bolt prior to thread rolling with a smooth-bore die of internal diameter slightly larger than the shank diameter but smaller than the rolled thread diameter.

Jan 4, 1977

By Y. Akin, M. S. Celik, T. Batar, F. Arslan

Despite its importance in various diverse industries, research on beneficiation strategies of boron minerals has not received enough attention. Boron minerals are primarily upgraded by wet processing methods. However, severe environmental constrains have accelerated the development of dry processing techniques such as calcination. Interestingly, the boron minerals colemanite, ulexite and borax undergo decrepitation, shrinkage and expansion, respectively, upon heat treatment. Each mineral then requires a different beneficiation scheme. In this study, laboratory and pilot-plant studies conducted in our laboratories on the calcination of boron minerals are briefly reviewed and their implications to commercial operations are discussed.

Jan 1, 1999

By Robert W. Bartlett

Heap biooxidation of sulfidic refractory gold ore requires large amounts of oxygen, as shown in Figure 1. Bacteria, Thiobaci/lus ferrooxidans, are donnant at oxygen concentrations below about 3% in air (1 ppm in aqueous solution) because ofmonod kinet­ics. Hence, the maximum possible utilization is only about 75%, and it may be much less than that due to poor air sweep effi­ciency. At the maximum oxygen utilization, an ore containing two percent pyrite requires nearly 100 cubic meters of air per tonne (4,000 cubic feet per ton). The stoichiometric air require­ment to oxidize arsenopyrite is similar to that of pyrite. While the leaching solution percolating through the heap introduces some dissolved oxygen, the amount is insignificant because of the low solubility of oxygen in water, 7 to 8 ppm at atmospheric saturation. There are only three ways to provide oxygen to the heap: either air flow by natural convection, diffusion of oxygen from the surface (through stagnant air in the air-filled void space in the heap), or forced air ventilation of the heap. Each of these processes will be reviewed.

Jan 1, 1996

By William H. Snyer

A relatively inexpensive, very fast response photo-optic/fiberoptic system has been conceived, constructed and employed by Denver Research Institute (DRI) to measure charge breakout uniformity on the surface of a very large ANFO detonation. The new equipment and technique was coined OWL (observation without leads). Its unique design provides the ability to monitor or measure detonation velocities and/or detonation breakout characteristics without fiberoptic or any other direct contact with the explosive. This system has proven to be versatile and has been used to measure surface breakout simultaneity on large ANFO detonations, munition case breakout times and velocity of detonation (VOD).

Jan 1, 1990

By S. Formby, J. Avraamides

Transportation of sodium cyanide from factory to minesite often attracts adverse comment from both the community and government agencies. In Western Australia the transportation of 30% w/w aqueous sodium cyanide solution raised fears in the community concerning the safety of such material in the event of spillage. The Chemistry Centre of Western Australia initiated a study of the effects of such a spill, to determine appropriate short and long term response strategies. Factors which were considered included the rate of hydrogen cyanide gas release under various climatic and soil conditions and the effect of alternative treatments in reducing such emissions. The data collected have been used to plan emergency response procedures.

Jan 1, 1989

By Charles J. Speake, Dennis R. Haley, Thomas E. Finch

As there exists a strong trend to computer assisted mine design, this twofold presentation will emphasize an examination of the parameters wed to create a mine design computer program. The program results are a first-order engineering design and evaluation of methods wed to handle the parting or inner burden found in thick-seam western surface coal mines. The alternative selections are draglines, backhoes, scrapers, front-end loaders, shovels, and bucket wheel excavators used in direct stow or haul-back techniques. The computer program wed in the design selection will be explained and typical input and output information shown.

Jan 1, 1980

By John Birkinbine

The iron industry of the United States, and, in fact, of the world, was established with charcoal as fuel. Long before the value of mineral coal was recognized, the carbonization of wood was carried on in connection with various metallurgical processes, but at the present time we look upon establishments using charcoal as the remnant of a former greatness, and are apt to sympathize with the operators because they have no other fuel to depend upon. In the iron

Jan 1, 1883

By Rilung Xu, Jerry C. Tien, Jian Liu

As underground mines become deeper and ventilation networs more complex, ventilation data becomes more complicated and voluminous, making timely ventilation planning and necessary changes more difficult. Oftentimes, ventilation engineers have to rely on special techques using graphs and schematic maps to carry out necessary ventilation planning [1, 4, 5, 6, 9, 10, 11, 12]. A different graphical method, similar to that reported by Taminago and Isobe [10], has been developed in China [13]. This method uses a two-dimensional diagram drawn from available ventilation survey results. It combines both the customary pressure-quantity diagram and ventilation schematic map, and can greatly expedite the interpretation of survey results, facilitate ventilation system design, short and long-range planning, and emergency planning.

Jan 1, 1993

By Jonathan J. Owen

We will describe modifications to air-sparged hydrocyclones (ASH) that enhance collisions and reaction of wastewater contaminants with sparged gas. These new ASH-based reaction chambers are combined with flotation tanks that are designed to optimize separation of bubbles and particles from water. In combination, these systems have achieved unprecedented removal of contaminants from industrial wastewater and process water while requiring smaller footprints with lower capital and operating costs. Real-world examples of chemical and nonchemical water treatments that demonstrate the outstanding flexibility and applicability of these systems are shown. Design enhancements that resolve the operational problems of traditional ASH are discussed.

Jan 1, 1999

By Steve Richards

Incorporating a bottleneck analysis into the mine plan can provide a significantly better basis to make economic decisions regarding materials handling systems. Every materials handling system has a bottleneck. The bottleneck at a mine may change over time as a function of location or time. Since a mining reserve is a finite amount and can usually only be mined once, knowing how the bottleneck changes can provide a critical backdrop to capital investment decisions, especially those affecting the materials handling system. A bottleneck analysis can better quantify the expected 'return and also indicate the optimal time to complete tile project.

Jan 1, 2002

The State of Western Australia has a land area of 2 525 000 km2, and is well endowed with minerals and petroleum products. In 1989 - 90 these products were valued at nearly A$10 500 million.

Jan 1, 1992

By Birger Schmidt

The design of underground nuclear waste disposal facilities poses new problems related to the requirement of long term safety against radionuclide migration. The degree and effects of rock disturbance caused by construction and by the long term thermal effects from the hot waste must be predicted with confidence. Computer modeling can, to an extent, be verified by accelerated near-surface tests. Credible extrapolation to deep, long-term conditions requires successful near-surface modeling verification, proper characterization of near-surface and deep rocks, and successful determination of in-situ stresses. Excavation induced disturbance may be assessed primarily by empirical evidence.

Jan 1, 1981

By Brian H. Zelenko, Patricia M. Perry

INTRODUCTION The environmental requirements of the next section of Washington, D.C. METRO subway tunnels present unique challenges to the Contractor. The 14th Street Tunnels contract includes twin 975 m (3200 linear ft) soft ground tunnels. A stringent environmental soil and groundwater monitoring and free product recovery program was specified by the owner. A project-wide dewatering program hinges on satisfactory completion of the environmental requirements. Implementation of the Contractor's environmental program is discussed, including the pros and cons of the program, as they relate to progress of the project. Environmental issues on tunneling projects have become an important part of the urban tunnel construction process. Delays associated with environmental issues can have a major cost impact on tunneling projects. This paper will discuss the first of five Washington Metropolitan Area Transit Authority (WMATA) tunnel and station contracts awarded in 1994. These contracts are part of WMATA's Fast Track Plan to complete the original 166 km (103 mile) system by 2001. As such, stringent environmental requirements have been specified as a part of these contracts to limit delays associated with local regulators in order that the tunnels may be constructed on schedule.

Jan 1, 1995

By Tim O’Neil

Many mining companies try to fight their way up from small operator and exploration company to major producer. Not many companies make it. Cambior Inc., formed in 1986, is one company well on its way to making it as a major operating company. In 1993, Cambior surpassed 15.5 t (500,000 oz) of gold production and began operations at its world class Omai gold mine in Guyana. At the same time, the company has embarked on a program of geographic and minerals diversification. Cambior, a Canadian company, now has interests in eight mines, three development projects and more than 100 exploration properties in North and South America. The company’s goal is to derive 70% of its income from gold and 30% from base metals and other minerals. Cambior’s moderate diversification into base metals gives protection against negative gold price fluctuations. It also balances the typically short term gold mines and the longer term base metal mines.

Jan 1, 1994

By Mason K. Banks

A process has been developed which produces spodumene concentrates assaying 6.0 pct Li20 and 0.45 pct Fe203, with 70 to 75 pct recovery of spodumene. Two flotation separations are required: the simultaneous removal of mica, feldspar, and quartz as a froth product using a cationic collector, and the subsequent removal of iron-bearing minerals as a froth product while spodumene is depressed as a tailing.

Jan 2, 1953

By H. I. Ashby

INITIAL development of the south orebody at San Manuel is being carried out from the No. 1 and No. 2 shafts. The haulage and grizzly levels are being driven to develop the upper one third of the massive hydrothermally altered and fractured monzonite orebody. This first haulage level has been placed at the 1475-ft level with a grizzly level 60 ft above. The grizzly level will be connected to all service shafts so that men and supplies can come down to the grizzly level and go to working places without congesting the haulage level. These connections are also a vital part of the ventilation plan. The haulage level is being advanced along the north and south fringes of the orebody and connections are being driven to the three shafts now under construction. The No. 1 and No. 2 shafts will serve the development work with supplies, skip hoisting, and ventilation at each shaft and the two shafts are connected on both the grizzly and haulage level.

Jan 7, 1954

By Prasannarao Dontula, Kal V. S. Sastry

Advances are made in the field of mineral processing on a continuing basis both in the industry and the academia. These advances do not always get used fully because of the inherent difficulties in the transfer of knowledge and reduction to practice. In recent years, knowledge engineering is being increasingly employed in other fields to overcome some of these difficulties. This paper presents a vision of how knowledge engineering can be applied to the benefit of the mineral processing industry and includes a discussion of associated principles, techniques, and advantages.

Jan 1, 1993

By Y. C. Kim

To generate a most profitable, ultimate pit limit is generally the first step in mine design. This paper presents a new graph theory oriented, optimum ultimate pit limit design algorithm which will maximize the total undiscounted net profit. This algorithm performs much better than the well known Lerchs-Grossmann algorithm, in terms of the reduction in computation time and computer memory requirements. This algorithm operates on many directed trees in a graph, where each vertex in a tree represents a block in the mine model. The formation of each directed tree is based more on the ore-waste support concept than the geometry constraints alone. The general procedures of the algorithm, programming considerations and two case study results are discussed in the paper.

Jan 1, 1992

By Tom C. Palanglo, Norbert Maerz

Control of crushing and grinding circuits ideally requires continuous particle size measurements on both in- and outgoing streams. Until recently, size distributions could only be obtained by screening methods, which were neither cost effective, frequent enough, nor timely. Input streams are often composed of large fragments, making screening prohibitive. Optical image processing systems, such as the WipFrag System, have been developed to the point that they are an extremely valuable tool to characterize, control, and fine-tune the comminution process. Although accuracy is less than that of screening, measurements are precise enough to detect relatively small changes in size distributions.

Jan 1, 2000