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By Gary A. Almeraris, Thomas F. Peyton

This paper describes the innovative procedures employed during the construction of 3 deep shafts within the confines of New York City. The shafts, which varied in diameter from 1.8m (6ft) to 7.3m (24ft) and had an overall depth of 199m (650ft), were excavated by both mechanical and conventional methods. These were subsequently concrete lined, clad steel riser pipes installed and associated surface structures were constructed. Tricky surface rock blasting coupled with the unearthing of unexpected obstructions caused constant uncertainty during the excavation phase. In addition, the necessity of handling men and material in restricted yet deep openings required the development of a safer and more productive shaft construction procedure.

Jan 1, 1989

By Colin C. Harris, Jie Zheng, P. Sornasundaran

Powder surface and polymer structural changes during stirred milling have been studied as a function of grinding time, solid concentration and polymer molecular weight. It was found that specific surface area of limestone particles can be increased over 100% by using polymer additives. Particle surface and polymer structure were also found to change during grinding. Powder surface and polymer properties have been determined using Surface Tension, Fluorescence, TOC and HPLC/GPC analysis, and surface and polymer properties are correlated with operating variables and the mechanisms involved are explored. Particularly, the fragmentation of the polymer molecules was found to occur during long term grinding and this was beneficial for ultrafine grinding.

Jan 1, 1998

By M. Abdi Oskouei

Some believe that Sustainable Mining due to impermanence of mining operation and adverse environmental impacts of mining, is an oxymoronTruly, no one can overlook these environmental impacts; however, a sustainable development is based on three elements Environmental, economical and social sustainability. In order to assess the relation between mining activities and sustainable development, not only environmental but also economical and social sustainability must be considered.Thanks to mine reclamation the adverse impact of mining on the environment can be reduced, meanwhile it will improve the social and economical condition after the mine-closureTo ensure that a mining operation is toward sustainable development goals, specific criteria and indicator frameworks have been established, in addition, for verification of our discussion the suitable selected reclamation plan for Bibishahrbanoo limestone mine of Tehran-Iran and its effect on sustainability of region has been studied.

Jan 1, 2011

By F. -U. Schneider, F. Wellenkamp

Based on previous investigations of ultrafine comminution in planetary ball mills, a new centrifugal mill has been developed which permits similar high stress conditions. Because this new type of mill is equipped with an immobile chamber, devices for measuring energy, for cooling the milling vessel, as well as, in continuous operation, for material feed and discharge can be more easily attached than to planetary ball mills. Observations of particle behaviour have shown that, in the case of dry grinding, most of the material is found on the mill walls even after short grinding times. Due to the fact that energy dissipation takes place mainly in the zone near the wall, a grinding system which reduces the amount of ball filling required is at an advantage.

Jan 1, 1995

By Greg Joachims

Composition of salt in the Permian Flowerpot Shale in northwest Oklahoma suggests that the salt in this formation was deposited in the early phase of solar evaporation. Brine produced through natural dissolution of the subsurface salt has netted very pure brines, with relatively low concentrations of magnesium salts that should result from late-stage precipitation of salt deposits from sea water. Over the last 100 years, extensive studies of sea- water evaporites, in relation to brine density, have been a topic of discussion. The development of evaporation models has facilitated the increased production and purity of solar salt (salt produced through evaporation of brine by the sun's energy). Conversely, this information can be utilized to gain an understanding of how rock-salt formations were precipitated from sea water by analyzing the elemental constituents of the rock salt and of the resulting brine. By evaluation of well-documented, phase-curve tables of sea-water evaporation, a basic theory can be formulated on how the Flowerpot salt unit was formed.

Jan 1, 1999

By W. W. Roepke, B. D. Hanson

A major problem facing the coal mining industry today is the need to meet more stringent dust standards due to quartz. When secondary suppress ion is not adequate, the time-consuming and costly cut-and-try method of modifying the mining machine is used in the hope that it will reduce dust generation. The Coal Cutting Technology Group, at the Bureau of Mines' Twin Cities Research Center, has developed an inter-active computer program for drum- type cutting systems to help identify, in advance, modifications that offer the best potential for reducing dust. The program, Relative Dustiness Indicator (REDI), evaluates machine dimensions, seam characteristics, and operator-controllable variables for dust generaton, energy, forces, and product ion.

Jan 1, 1986

By William J. Gregg

Mechanical testing results on oriented Devonian gas shale core throughout the Appalachian basin show a preferred fracture direction perpendicular to bedding. The preferred direction is generally parallel to the Allegheny Front, but is only coincidentally parallel with in-situ stresses in some areas of the basin. The strength of the preferred orientation of induced fractures decreases with distance from the Front. It is suggested that strain related to Paleozoic deformation is responsible for this mechanical fabric and thus the direction of induced fractures in laboratory tests may not be of use as indicators of in-situ stress orientations as previously suggested.

Jan 1, 1986

By Alain A. Sonntag

This paper presents the most recent developments in KREBS technology directed towards treating higher throughputs, increasing efficiencies and providing further improvement in SX technology with a new concept: the submerged launder. Industrial plants built in the last past few years and using these improvements are described.

Jan 1, 1989

By Michel Grenier, David A. Young, Brent Rubeli, Mahe Gangal

This work forms part of a study being conducted into the feasibility of constructing a prototype Load Haul Dump (LHD) vehicle for operation in underground Canadian mines. A series of in-laboratory assessments were performed to determine the relative contributions of a Deutz F4L912W (54 HP- conventional vehicle engine) and a Deutz F2L 2011 (31 HP hybrid vehicle engine) to diesel emissions concentration during mine transient duty cycles and steady-state operating modes respectively. Results indicate significant reductions in the quantity of gaseous and particulate emissions with the application of the hybrid system and a high-efficiency ceramic element filter. This paper describes the engine test protocols and the results of this laboratory study.

Jan 1, 2006

By W. A. Cincilla, Z. T. Bieniawski, E. Unal

Although coal mine tunnels such as the main haulageways or roadways are the lifelines of coal mines, little attention has been paid to them in terms of pre-construction planning and design. This paper presents the results of research aimed at improving design methods for coal mine tunnels. Studies of the current practice and design needs in the United States were performed for coal mine development entries. A design approach evolved for coal mine tunnels is presented. It is based on field investigations and laboratory model studies aimed at integrating into reinforcement guidelines for coal tunnels. An up-to-date bibliography on coal mine tunnels is provided.

Jan 1, 1981

By Fathi Habashi

At the Duisburger Kupferhütte plant in Germany, pyrite cinder is collected from the sulfuric acid manufacturers in that country and processed to recover the nonferrous metals contained in the cinder, before charging it to the blast furnace for iron recovery. A typical analysis of the cinder is given in Table 9-1. The pyrite cinder is mixed with NaCl and treated continuously in a multiple hearth furnace. The evolved gases are scrubbed with water to form a weak acid which is used for the leaching process. Each batch requires about 2 days for leaching. The concentrated leaching solution obtained in the first 15 to 20 hr is sent for copper recovery, while that subsequently obtained, being poor ill metal content, is recycled. The residue, called purple ore, now a high-grade iron ore (61-63 % Fe); is sintered and delivered to the blast furnace.

Jan 1, 1970

By Guillermo Chong Díaz

A brief overview of industrial mineral exploration and exploitation in Chile is given. World class deposits of salt, lithium, nitrate, and iodine are present in northern Chile. The potential for further exploration and exploitation of these deposits, as well as the substantial reserves of other mineral commodities such as gypsum, anhydrite, volcanic rocks, and borates are discussed. In conclusion, industrial minerals mining in Chile has considerable potential, particularly as joint ventures between foreign and domestic companies. This has been demonstrated in the extraction of nitrates, lithium, iodine, and diatomites. However, as outlined in this paper, a number of factors need to be overcome before the true potential of the Chilean industrial minerals industry can be realized.

Jan 1, 2001

By D. I. Phillips, P. J. Bethell

This paper focuses on the -1/2 mm cleaning at Elk Run Coal. The original circuitry incorporated desliming cyclones. Problems with slimes entrainment in the cyclone underflow (froth cell feed) resulted in poor froth cell selectivity. Laboratory test work led to the installation of high frequency desliming screens. Consequently, great improvement in cell performance was brought about by enhanced desliming with the ability to use split flotation. The modifications resulted in significant improvement in total plant performance and overall yield while maintaining clean coal quality.

Jan 1, 1987

By S. Eugene Sankey, Geoffrey L. Payne

Fundamental choices in flocculant selection often come down to the lower cost of solid grade products versus the convenience of liquids. The ideal product would be a low cost solid grade flocculant which requires minimal handling and no sophisticated dissolving equipment. Recent polymer developments have lead to the commercialization of a limited range of dry polymers that can be screw fed at controlled rates directly to process streams without the need for predissolving. Other developments include dry polymers that can be directly added to mix tanks without the need for sophisticated wetting systems. The latter will make dry flocculants especially attractive for smaller users. Examples of these new products and their application in industrial and municipal waste treatment will be provided.

Jan 1, 1994

By R. B. Inturi, R. G. Reddy

Solid-state reduction of roast Movat chromite ore with carbon was carried out as a function of the C/FeO ratio at temperatures ranging from 800°C to 900°C. The reduction was studied using thermogravimetric analysis (TGA). A two¬stage mechanism consisting of the reduction of FeO with carbon monoxide and the regeneration of CO by the oxida¬tion of carbon with CO2 was proposed. The rate-controlling step is the carbon oxidation reaction. A kinetic equation, that of random nucleation, was proposed. The activation energy for the reduction was determined to be 55,800 J/mole and is compared to those activation energies determined for other chromite ores.

Jan 1, 2000

By D. E. Ranta, M. W. Springett

During the 1970's geostatisticians were often accused of not paying sufficient attention to geologic features in the computerized generation of ore reserves. Unfortunately this charge was all-too-often justified and the results of such studies tended to be oversimplified and failed to reveal the full potential of computerized reserve estimation and geostatistical methods. There were some notable exceptions to this trend. Techniques were described that paid a great deal of respect to the geologic characteristics peculiar to certain deposits (Rendu J-M, 1984; Barnes T. E., 1982). At Gold Fields several techniques have been developed for handling the geologic characteristics of orebodies for reserve estimation purposes. These have developed over time and the evolution of their adoption has been a reflection of our own learning experience from the practical application of computerised reserve estimation on many precious metals deposits.

Jan 1, 1992

By R. Debkowski

The current underground infrastructure of an old monumental salt mine along with using it as a tourist, museum, nature, resort, conference and cultural events place is presented in the paper. At present, mainly in the monumental part of mine, only a small part of the historical chambers, which together with galleries form a tourist route available to visitors. Moreover, the essential activities aimed to make the tourist route more attractive and to change the decor of the underground sites are discussed.

Jan 1, 2006

By Peter Keppler, Stephen D. Bundy

"Due diligence" is a review or audit of a facility or business to assess and quantify risks and operating status before an acquisition. Due diligence findings can be used to negotiate the price, general terms, and indemnification provisions in the purchase and sales agreement. In addition to assessing out- standing liabilities, necessary capital improvements, and the adequacy of operating budgets, due diligence should include "nontechnical" considerations, such as local community acceptance and relations, and the effect on the company's public image and operations. This paper will discuss how these considerations can be addressed in the due diligence process and factored into the transaction. Also, innovative means for risk reduction and risk transfer, during and after the transaction, will be discussed.

Jan 1, 2001

By R. Llerena, P. Dunstan, R. L. Amelunxen

A single four feet diameter cell, treating a Cu/Mo rougher concentrate, has been fully instrumented and linked to a Distributed Control System. This has enabled the writers to further understand the mechanics of operation of the cell, particularly that of the "TRANSITION ZONE". This is the volume between the feed port and the pulp-froth inter- face. The results have shown a need for the re-designing the control loops whereby the Transition Zone volume (or pulp level ) becomes the single most important control parameter to achieve the de- sired recovery. Air consumption, previously thought to have played this role, is now kept at precoalescence level s for maximum efficiency.

Jan 1, 1988

By R. K. Mehta, U. Cetin

The Nevada Test Site is located approximately 100 km (65 miles) northwest of Las Vegas, NV. The site was primarily used by the Department of Energy for the field testing of nuclear weapons and has been contaminated by several million cubic feet of low-level radioactive wastes, heavy metals, explosive materials, and volatile and nonvolatile organics. The transportation and leaching of these contaminants are creating serious environmental problems. The purpose of this study is to examine pozzolan, a natural alumina-silicate mineral, as a possible replacement for the existing impermeable clay barriers. In the first phase of this study, radionuclide sorption characteristics of pozzolan were investigated. This paper presents the results of the adsorption tests for the target radionuclides.

Jan 1, 2000