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By Fred V. Carrillo

California was the leading state in industrial mineral production value with an estimated value of nearly $2 billion. In total value of U.S. non-fuel mineral production estimated for 1992 by the U.S; Bureau of Mines, California ranked second; 81 % of California's total production value was derived from industrial minerals. California led all other states in the production of boron minerals, portland cement, diatomite, calcined gypsum and construction sand and gravel, and ranked second in potash and soda ash production. California's five leading industrial minerals in terms of value were portland cement, construction sand and gravel, boron, crushed stone, and soda ash. California had 13 additional industrial minerals production with reported sales of over $1 million including; industrial sand and gravel, magnesium compounds, lime, salt, potash, natural sodium sulfate, clay, feldspar, crude gypsum, pumice, dimension stone, calcium chloride and perlite.

Jan 1, 1995

By S. Pignolet-Brandom, E. Fregeau-Wu, I. Iwasaki

To recycle steelmaking slags for their iron, manganese and lime contents, removal of the phosphorus-bearing dicalcium silicate and calcium phosphate is essential. Slow-cooling of slags was necessary to promote sufficient grain growth to achieve liberation. In situ grain size distribution determination showed that a high soaking temperature, a long soaking time, a very slow cooling rate and the addition of fluorspar promoted grain growth. High gradient magnetic separation on slow-cooled slags removed much of the dicalcium silicate. Liberation modeling was used to discuss the breakage and beneficiation characteristics of the slow-cooled slags.

Jan 1, 1993

By Timothy M. Dyhr, Marie Garrett

The Cannon Mine gold project has been perceived as unique for being developed in an area characterized by orchards and suburban residences. The Cannon Mine was permitted and developed successfully in this setting. However, the ability of companies to permit, develop and operate mines in mated areas is becoming more difficult as a result of opposition by residents and increasingly stringent regulation. The challenge to the mining operator in the future on otherwise economically attractive mineral deposits will be the ability to explore and develop these types of projects successfully and cost- effectively

Jan 1, 1987

By S. Lin, Y. J. Wang

Fan stall is a notorious phenomenon of axial flow fans. When multiple fans of this type serve a ventilation system, their mutual impacts on the stability of the ventilation system are very complicated and not well understood. Results from laboratory experiments indicated that, when a fan is working across its stall zone (i.e., the pronounced trough on the fan characteristic curve), some branches in the system may suffer abrupt and even drastic changes in air quantity and pressure. The quantity range of the fan that causes the abrupt change is called an unstable operating range. The corresponding quantity range of a branch is called a nonachievable quantity range of the branch, because any quantity within this range cannot be achieved without changing some parameters of the ventilation system (e.g., branch resistances). This paper discusses these important characteristics of ventilation systems by using results from tests on laboratory tubing networks.

Jan 1, 1998

By David Royston

Conventional straight-radial SAG mill pulp lifters suffer from incomplete discharge of the rock portion of the charge. The resulting backflow of undischarged rock limits pulp lifter performance and is the major source of wear in pulp lifters. Backflow is increased in pulp discharge cone systems where multiple channels converge towards the central diversion cone. This paper covers recent experience with pulp lifter and discharge cone design supported by a single particle motion model that illustrates the discharge and backflow characteristics of pulp lifters, including the impact of discharge cone configuration.

Jan 1, 2005

By Fred D. Wright

In this paper the principal theories used to design roof bolting systems are presented and discussed. Then the characteristics of various types of roof bolts are presented and finally the interaction between rock and roof bolt characteristics on choice of roof bolts is discussed. Theories can be considered design tools which may or may not be appropriate for a specific situation. It is good for a design engineer to have a number of such tools available and also important that he understand their good features as well as their limitations. Hence, some of the principal theories and classification systems used for design of roof bolting systems are discussed first.

Jan 1, 1982

By A. Maréchal

It has been shown since a few years that the problem of estimating recoverable reserves should be solved by using specialized statistical techniques : whenever the selected blocks are chosen without any other constraint than a cut-off grade criterion, the problem of estimating the corresponding tonnage-grade curve is resolved by estimating the local histogram of block grades. Two major statistical techniques are currently used by geostatisticians to estimate local histograms : the "average conditional distribution" technique (Parker, Journel, Dixon 1979) and the disjunctive kriging technique. (Matheron, 1976, Jackson, Maréchal, 1979). Both have proved to be applicable in practice, with their pros and conconcerning their practibility and versatility.

Jan 1, 1982

By R. E. Wardwell, J. D. Nelson

The design of cover systems for reclamation schemes in tailings requires estimation or determination of tailings materials properties such as compressibility, shear strength, and consolidation characteristics. It is very difficult and expensive to obtain truly undisturbed tailings samples for laboratory testing. In situ testing methods have been developed for economically obtaining large amounts of information. Two of these methods are described, the piezocone and the flat plate dilatometer. Both of these methods provide a rapid means of detailed material identification in a nearly continuous fashion for the entire depth investigated. The equipment is described and typical data from a uranium tailings impoundment is presented. The results are compared and the advantages and disadvantages of these methods are discussed.

Jan 1, 1987

By J. A. Rose, A. S. Atkins

Environmental awareness has become a paramount consideration in the issue of planning and licensing arrangements for the disposal of wastes associated with mining operations. In this con- text the disposal of liquid tailings is a difficult and controversial problem with regard to environmental surface disposal. The paper outlines the use of Information Systems for decision support in the safe and environmental disposal of liquid tailings linked to conventional coarse refuse operations. This offers both an economic and an aesthetic approach to a historical perception of waste tipping in the underground coal extraction industry. The paper will demonstrate a prototype system that incorporates multimedia facilities which include data such as; voice comments, site photography, site plans and fluid flow circuits.

Jan 1, 1996

By M. T. Ityokumbul

Flotation columns and their variations are increasingly replacing conventional cells in mineral-processing circuits. While the operational characteristics of columns differ from those of conventional cells, the same scale-up methodologies are being employed. This practice may be attributed to a poor understanding of the factors that control throughput. The use of tall flotation columns is frequently justified because of the need for an increased particle residence time. However, it is shown that longer particle residence times alone do not translate into increased recoveries. In this paper, throughput data from several industrial flotation-column installations is presented. Also, an attempt is made at using dimensional analysis to provide a scale-up methodology for the factors controlling column throughput.

Jan 1, 1997

Little knowledge is available that considers the effects of continuous miner position on the possible respirable dust exposure of the remote mining-machine operator. Such information could be very useful for increasing the awareness of the remote operator as to those parts of an extended cut that generate higher levels of respirable dust. This data could be used to develop guidelines for positioning the remote operator to reduce his potential exposure. This work details the effects of continuous miner position on dust levels measured on the machine and at the remote continuous miner operator location.

Jan 1, 2000

By W. M. Hart, Q. H. Shen, J. S. Chen, S. S. Peng

The automatic data-acquisition systems that are now available can continuously monitor and record changes in leg pressure and changes in advancing ram stroke in every shield. These systems can record shearer position at any moment during a mining operation. The data obtained can be used to improve production and maintenance management and can be used to provide better roof control at the longwall face. Research now being conducted jointly by West Virginia University and Cyprus Amax Coal Co. is aimed at developing a longwall-management system (LMS) for mine operators. The LMS software package, which works in the Microsoft Windows NT environment, performs data interpretation and analysis, production management, maintenance management and ground-control management for longwall mining.

Jan 1, 1997

By S. W. Clark, R. Meglen

A seismic refraction survey of selected environs of Brewster Phosphate's Lonesome mine near Bradley, FL identified various layers of overburden, minable matrix (ore body) and basement (i.e., bedrock) that correlated with core logs. Bivariate correlation procedures determined that statistical relations existed between mining parameters and seismic velocities. For instance, a correlation of approximately -0.6 was inferred between P wave velocity and ore grade.

Jan 1, 1990

By Paul M. Godlewski, Gerry Millar, Harvey W. Parker

Recently, over 70 railroad tunnels in the western USA have been enlarged and rehabilitated "live track," utilizing modern excavation and lining methods, in most cases to clear the larger double-stack container cars. This paper presents the general conditions of the tunnels and the technical aspects and costs of the rehabilitation of approximately 40 kilometers of tunnels, which range in length from a few hundred meters to 13 kilometers. Concrete-lined tunnels were rehabilitated by grouting and rock bolting, while unlined or timber-supported tunnels were relined with shotcrete and rock bolts. High output lining methods were required because of limited track time. Enlargement has been accomplished primarily by carving notches out of the concrete linings with a roadheader, or occasionally with saws. Unlined tunnels were enlarged by drill-and-blast or roadheader excavation.

Jan 1, 1991

By K. N. Han, Y. Guan

The dissolution behavior of silver and copper from silver/copper alloys in ammoniacal solutions was investigated using a rotating disc. Oxygen was used as an oxidant. The effects of the alloy composition, concentration of lixiviants, stirring speed and temperature on the overall dissolution kinetics were studied. Three silver/copper alloys (containing 76.7, 46.9 and 24.1% silver) were used in this study. The rates of dissolution for these alloys were compared to that of pure silver and copper under the same testing conditions. Emphasis was given to the galvanic effect on the overall dissolution rates.

Jan 1, 1995

By Nikolay M. Sirakov, Michael L. Feves, Rumen P. Mironov, Daniel R. Hack

Subsurface investigation of sand and gravel deposits has generally been limited to test pits and borings. These techniques are problematic in terms of the accuracy, usability, and cost of the final data. Innovations in the application of geophysics have been gaining acceptance in the aggregate industry, especially to determine depth to bedrock and the extent of uneconomic inclusions. This paper presents a system to optimize the processing and evaluation of electrical resistivity data. The system uses 3D separation, geometrical reconstruction, and visualization of subsurface objects.

Jan 1, 2002

By Nora M. Hutt, Kevin A. Morin

One technique for controlling ongoing acidic drainage is to relocate and submerge net-acid-generating waste rock in a lake or water-retaining impoundment. This can lead to the overall improvement of water quality and the reduction In short-term environmental liabilities. A case study of this technique is the Eskay Creek Mine in northern British Columbia. Some findings of the study are: (1) the addition of lime to each truckload of rock, based on its rinse pH, neutralized the accumulated acidity and suppressed the accumulated-metal release, (2) only 10-20% of the dump's neutralization potential had been consumed when acidic drainage appeared, (3) water chemistry in the watershed recovered roughly three years after relocation, and (4) environmental liability was reduced due to the cessation of on-land acidic drainage with no degradation of lake chemistry.

Jan 1, 2000

By K. A. Natarajan, Namita Deo

Strains of Bacillus polymyxa, preadapted and grown in the presence of corundum, were found to be capable of the efficient separation of hematite from alumina. Results of tests performed using binary hematite-corundum and ternary he- matite-quartz-corundum mixtures in the presence of cells and metabolic products separated from the adapted bacterial culture indicated that more than 99% of the hematite could be efficiently separated through selective flocculation after desliming. It was found that alumina-specific bioproteins and other nonproteinaceous compounds were secreted by bacterial cells after adaptation to the mineral. The utility of this bioprocessing is demonstrated in the removal of iron from bauxite ores through selective

Jan 1, 2000

By T. Tamagawa, S. H. Tabaian, I. Iwasaki, N. X. Fu, M. Kobayashi

A gaseous chlorination process for the hydrometallurgical treatment of a chalcopyrite concentrate was investigated. The overall process is visualized to consist of low-temperature chlorination -selective oxidation, followed by aqueous chloride leaching and SX-EW for producing electrolytic copper, elemental sulfur and ferric oxide. In this article, the chlorination phase of the process is described. Initially, the chlorination behavior of chalcopyrite concentrate micropellets was investigated using a small batch-type fluidized bed reactor. The optimum conditions thereby established were used in continuous chlorination tests. The chlorinated products thus prepared were used in the selective oxidation phase of the investigation.

Jan 1, 2000

By A. J. Friedrich

Conveyor belts are designed to go unnoticed. When they work well, they attract little attention. When they are not doing the job right, it is noticeable, and they need to be fixed immediately. Vulcanising contractors compete for the maintenance of belts in mining/quarrying and general materials handling worldwide. Damage repair is approached in similar fashion. The damaged section of belting is normally cut out and discarded, and the belt re-spliced using hot vulcanising, Cold splicing, or mechanical fasteners/clip joints. However, there is a cost-effective alternative, alleviating the need to remove damaged sections which are often perfectly recoverable. This is the use of cold-curing repair resins and adhesives.

Jan 1, 2000