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By F. E. Kottlowski

Widespread high-calcium limestones in New Mexico region are low -in magnesium, but some units include shale interbeds deleterious for sulfur removal usage. Thick limestones in Mississippian Escabrosa, Lake Valley, and Leadville, Pennsylvanian Madera and Hermosa, Pennsylvanian-Permian Horquilla, Permian Hueco and Capitan, Cretaceous U-Bar, and some Cenozoic travertines are high-calcium units. Significant outcrops are in mountains of southwestern, south-central, central, southeastern and north-central New Mexico, southeastern Arizona, southwestern Colorado, and northwestern Chihuahua. Coal-fired powerplants are mainly in northwestern New Mexico and eastern Arizona, thus transport is mainly by railroad.

Jan 1, 1994

By John W. Harshbarger

The Upper Santa Cruz Groundwater Basin lies in the drainage area of the Santa Cruz River in Arizona, and extends upstream from the community of Rillito to the international boundary, see Figure 1. The principal water use area lies between and includes the cities of Tucson and Nogales. A subsurface geologic barrier near Rillito provides a reasonable dividing line between the groundwaters of the Upper and Lower Santa Cruz Basins. The Upper Basin contains the Tucson and Sahuarita-Continental critical ground- water areas. The Tucson Water Use Area encompasses the Tucson metropolitan area and extends from the northern boundary of the Basin south to the boundary between the Tucson and Sahuarita- Continental critical groundwater areas near San Xavier. The San Xavier Use Area is the San Xavier Indian Reservation. The north and south boundaries of the Continental Use Area coincide with the limits of the Sahuarita-Continental critical groundwater area. The first study of groundwater in this valley was initiated by Dr. G. E. P. Smith in 1905 and the results were published in 1910, followed by a series of bulletins of the Arizona Agricultural Experiment Station, University of Arizona, covering the general field of groundwater development and utilization. Beginning in 1939, the Ground Water Branch of the United States Geologic Survey, in cooperation with the Arizona State Land Department and the Arizona Water Commission (AWC), have published a series of bulletins concerning groundwater occurrence and utilization in various areas of the state. In 1975 and 1977, the AWC published the "Arizona State Water Plan" (1), comprising a detailed inventory of water availability and use in the State of Arizona, and a study of alternative futures.

Jan 1, 1979

By Steven M. Bishoff

The reclamation of surface land areas disturbed during the course of coal recovery became a major, universal consideration upon the implementation of the Surface Mining Control and Reclamation Act of 1977. This legislation not only established reclamation as an absolute requirement, but also presented guidelines for reclamation standards and required bond-posting procedures to assure completion of the reclamation process. The Office of Surface Mining was established to enforce the provisions of the Congressional mandate by promulgating specifically detailed regulations and supervising the State participation in this regulatory process. The major operational consequences of the reclamation-related provisions of the Act and the OSM regulations are the increased costs and complex procedures necessary to accommodate the regulatory authorities. It is anticipated that many of these costs and procedures have not been adequately evaluated by either the coal operators or the regulatory bodies. It is, therefore, necessary to proceed with an examination of the general reclamation processes, the effect of these processes on product costs, and the methods, if any, which may be utilized to minimize their impact on the overall operation.

Jan 1, 1981

By K. N. Han, X. Xie

The dissolution behavior of palladium powder in thiourea solutions was investigated. The variables studied were temperature, stirring speed and the concentrations of thiourea, acid and ferric ion. Palladium was found to be soluble in thiourea solutions in the presence of an oxidant such as ferric ion. The dissolution of palladium in thiourea solutions was believed to be chemical-reaction controlled, with an apparent activation energy of about 25.3 kJ/mol.

Jan 1, 1997

By Richard A. Bideaux

During 1977 and 1978, a comprehensive study was made of the drill-hole data obtained by Urangesellschaft, USA, from their Juniper Ridge, WY, uranium deposits. This included uranium grade data acquisition, application of a variety of mineral deposit modeling techniques, and estimates of minable reserves, which pointed towards a possible production decision.

Jan 1, 1979

By K. A. Natarajan, K. S. N. Murthy

Growth of Thiobacillus ferrooxidans on pyrite mineral surfaces and in 9K leach media was studied through estimation of bacterial protein in the different phases. Bacterial attachment was found to be governed by particle size of the mineral, period of incubation and by stationary or agitation conditions used during incubation. Increased bacterial growth in the liquid as well as on the solid phase was observed with decreasing particle size and increasing incubation periods. Increased bacterial attachment to pyrite mineral surfaces was observed to promote iron dissolution.

Jan 1, 1993

By W. G. Cornwall

The mining field, inclusive of the treatment plant is located in the foothills, five miles inland from the northern coast of Viti Levu, the largest and most important island of the Fiji Group. Gold and silver occur as tellurides, associated with the sulphides, and as minor occurrences of electrum.

Jan 1, 1975

By K. A. Natarajan, M. K. Yelloji Rao

Significance of grinding media wear and its effect on chalcopyrite flotation are discussed. Laboratory marked ball wear tests were conducted grinding chalcopyrite ore and quartzite dry, wet, and with collector added during grinding. The effects of oxygen and nitrogen on ball wear were evaluated by the addition of chalcopyrite mineral while grinding quartzite. The effect of dry and wet grinding on chalcopyrite flotation was also studied. Results show abrasive wear is greater in quartzite grinding than in grinding chalcopyrite. Oxygen increases the corrosive wear of high carbon low alloy steel balls in the presence of chalcopyrite ore. Chalcopyrite flotation was retarded due to wet grinding in the presence of oxygen. Though collector reagent increased the media wear, it improved the flotation of chalcopyrite. Probable electrochemical reactions encountered in a grinding mill are outlined.

Jan 1, 1991

By R. K. Singhal, R. Kolada

A variety of equipment is wed to surface mine oil sands, including bucket wheel excavators/conveyors, draglines, hydraulic shovels, and off-highway trucks. This paper examines the existing mining schemes and equipment wed. Several proposals to improve mine productivity have been presented.

Jan 1, 1988

By Shiro Ishii

When construction sites are in a densely- populated area or near roads, railroad or river, restrictions upon the ways of handling and using explosives such as dynamite and large demolition equipment are being increasingly stringent, in consideration of environmental pollution such as noise, vibration, dust, flyrocks etc., and safety precaution. In view of this, the development of safe and pollution-free technology for demolishing rocks at mines and reinforced concrete structure at building sites is strongly required. To meet such requirements, the demolition by means of expantion of mineral substances has been considered long before. Recently with the demolition technique using non-explosive demolition agent developed by ONODA CEMENT CO., LTD., holes are drilled into substances to be demolished, such as rocks and concrete before-hand. Then, slurry of such agent mixed with an appropriate quantity of water is poured into the holes. It hardens and expands with the passage of time, and the expansive stress reaches more than 3m/m2 in 10 to 24 hours. This expansive stress causes the material to crack. In this article, descriptions of the non- explosive demolition agent, BRISTAR manufactured by ONODA CEMENT CO., LTD., TOKYO, JAPAN, are given briefly with regard to its physical and chemical properties and its method of use; and the way it is used at an actual construction site is reported.

Jan 1, 1982

By Viktor Tokle, C. W. Dawson

The Devico directional core drilling system and its capabilities are described, with reference to other directional drilling technologies and the advantages and disadvantages of these systems. The advantages and disadvantages of a number of borehole navigation systems are also presented. A discussion of the applications of the technology follows, illustrated by case histories. Finally, the environmental impacts and benefits of the technology, in comparison to more conventional systems, are presented.

Jan 1, 1999

By A. M. Tunstall

Blasting is commonly viewed separately from mechanical handling and crushing. This view is misleading because the degree of fragmentation achieved by blasting can have a significant effect on the efficiency of these processes and, hence, on the overall cost of the mining operation. In this paper, aspects of blasting and crushing and their interaction are examined. A case study is also presented that dramatically illustrates the influence of blast fragmentation on subsequent processing and on the financial implications involved

Jan 1, 1997

By T. R. Raponi, D. Barnes

The Williams Mine mines and mills 6000 t/d (6600 stp’d) of gold ore using SAG/ball milling, leaching and CIP, electrowinning and refining. Electrowinning, high-pressure cathode washing, filtering, retorting and refining are based around the use of knitted stainless steel mesh cathodes. Their primary advantage over conventional steel wool cathodes is that electrowon gold can be washed off and the cathode can then be reused. Typically, the knitted cathodes have a useful life of up to 15 months. Gold production of up to15 t/month (50,000 oz/month) is easily processed with this system. Presented is a description of this operation, including a review of the equipment and performance data.

Jan 1, 1992

By J. F. Abel, R. J. Spengler

Convergence measurement across the 17.4-m (57-ft) high shaft station/loading pocket at Mt. Taylor provided continuing verification of stability and safety. Three levels of instrumentation, consisting of three lines each, were installed and monitored. The instrumentation showed that the flexible lining restrained the adjacent rock. The flexible lining consisted of pea gravel with neat cement between rock and liner plate, wooden crush blocks between liner plate and steel ring beams. The loading pocket is elliptical, 11.6 x 9.6 m (38 x 31.5 ft) inside diameter. The crush blocks were designed to allow 15 cm (6 in.) of convergence. Maximum predicted convergence was 7.0 cm (2.75 in.), and 5.7 cm (2.25 in.) was measured. Convergence measurements also demonstrated decreasing deformation with respect to elapsed time and distance from the measurement station to the temporary bottom of the shaft excavation.

Jan 1, 1987

By Fathi Habashi

THE UNIT process of adsorption involves two steps: 1) Loading of the adsorbent. 2) Recovery of metal values from the adsorbent. Charcoal is the adsorbent commonly used in extractive metallurgy. The discovery of the adsorptive power of charcoal from solutions is generally accredited to Lowitz (1785), who observed that several dissolved organic substances were precipitated on charcoal. Graham was the first to demonstrate that inorganic substances were also adsorbed on charcoal. In 1830, he reported that iodine dissolved in KI solution was adsorbed on charcoal. Also calcium ions were adsorbed from limewater, as were lead ions from lead nitrate solution. The use of charcoal in metallurgy was first applied

Jan 1, 1970

By W. C. Smith

Even with conservative mine planning, rib instability can progress from a nuisance to a major safety hazard. This Bureau of Mines paper examines the mechanisms of progressive rib failure in high mine openings and discusses techniques to control rib slabbing. A field test site in a longwall mine was instrumented to investigate rib behavior during mining. While data analysis showed minor pillar dilation. sporadic zones of progressive rib instability were detected that culminated in eventual rib failure. The failure occurred despite conservative pillar dimensions and shallow depth. Models were used to demonstrate the mechanisms of rib failure and then evaluate the influence of support and other mine-related parameters on rib behavior.

Jan 1, 1991

By D. C. McDonald, P. R. Whincup, H. Duke

Due to grade, overburden depth and stability and the presence of groundwater it was considered impractical to recover gold contained in unconsolidated palaeochannel sediments by conventional mining, dredging or borehole mining techniques. A series of field experiments was conducted to determine the feasibility of recovery of gold by in situ leaching from sediments located at a depth of about 80 metres. The test wellfield site and plant are described together with field test procedures, results and wellfield rehabilitation procedures. Choice of sodium cyanide as leachant and laboratory testing are discussed in relation to groundwater and sediment chemistry and problems encountered in field tests.

Jan 1, 1989

By C. A. Roberts

What are the benefits and limitations of financial analysis software as a decision making tool in the mining industry? Traditionally, the assumptions and simplifications imposed by complex and uncertain information have been viewed as the main obstacle to reaching an optimum decision. Recently, however, phenomena such as corporate culture and power structure have received increasing attention as significant influences on organizational decision making processes. Studies of these phenomena have suggested an alternative way of understanding decision making processes and an alternative view of the role played by computer analysis in such processes. This paper presents these two views of decision making, and examines what each implies about the role of financial analysis software as a decision making tool in the mining industry.

Jan 1, 1992

By G. T. Adel

The flotation behavior of a -28 mesh Pittsburgh No. 8 coal sample is investigated through the use of Scanning Electron Microscopy in conjunction with Image Analysis. Release analysis is used to generate the flotation products, which are then characterized to provide the particulate composition in terms of pyrite, mineral matter and carbonaceous material. The results of this investigation indicate that the material recovered in the first stage of release analysis tends to be well-liberated carbonaceous material. This is followed by an increase in the recovery of middlings and fines in the later stages of the process. Any free carbonaceous material remaining in the tailings from the release analysis test tends to be associated with the very fine sizes (-400 mesh). Pyrite recovery is attributed to the hydrophobicity provided by small inclusions of carbonaceous material, since the amount of truly liberated pyrite particles (i.e., 100% pyrite) present in the sample is found to be negligible.

Jan 1, 1994

By J. P. Golightly

The structure and occurrence of nickeliferous laterite profiles are described and explained in terms of mineral solubility and drainage conditions. Complete profiles, from top to bottom, include: limonite zone; nontronite or silica zone; and saprolite zone. The middle zone is present only where drainage is sufficiently slow to allow saturation conditions to build up with resulting quartz or smectite precipitation. This precipitation may occur in any climate at a water table or in tropical climates with a long dry season. The degree of serpentinization of the laterite parent rock is important in determining the nature of the saprolite zone. Unserpentinized peridotite produces saprolite ores with hard residual rock cores, nontronitic or amorphous saprolitic rims, and fracture fillings of garnierite and quartz. Ser-pentinites yield relatively homogeneous serpentine saprolite, with minimal quartz or garnierite.

Jan 1, 1979