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By G. Jeffrey Taylor

The environment at the lunar surface is drastically different from the one we are used to on Earth. The Moon has one-sixth of Earth's gravity, virtually no atmosphere, a surface bathed in radiation and micrometeorites, large temperature gradients, low seismicity, and a dusty, rubbly surface. To successfully mine and process materials on the Moon and to mitigate degradation effects in the hostile lunar environment, these factors require new designs for equipment and development of new techniques and technologies.

Jan 1, 1990

By S. R. Clifford

Organic contaminants can be removed from river sediment using conventional flotation methods. Organic contamination in sediments is one of the most significant pollution problems facing the Great Lakes region. Using conventional flotation, the majority of the organic contamination can be collected in a concentrate, leaving a "clean" tailings. This provides a cost savings by reducing the amount of material requiring further treatment. The concentrate can then undergo additional flotation stages, or other contamination removal procedures, to further remove the organic contaminants.

Jan 1, 1994

By Steven G. Vick

Not too long ago a mill superintendent, when asked where his tailings were being disposed, could simply shrug his shoulders and point to the open end of the thickener discharge pipe. This “out of sight, out of mind” approach to tailings disposal is a practice of the past. Today there are very few planned hardrock or energy-related mining facilities where tailings disposal has not been identified as the major area of impact and controversy. In fact, development of some ore bodies has been stymied altogether by lack of suitable sites or methods for tailings disposal. The bottom- Iine result is that tailings disposal often controls the permitting lead time and has a significant influence on construction cost (up to 2070 in some cases) of new minemill complexes. The following article, the first in a series of three, explores technical background and historical perspectives on siting and design of tailings impoundment facilities.

Jan 6, 1981

By Wang Dianzuo, Luo Lin, Hu Yuehua, Qiu Guanzhou

This paper introduces a novel classification approach named the flotation classification approach which works by controlling interactions between particles. It differs considerably from the conventional classification processes operating on mechanical forces. In the present test, the micro-bubble flotation technology is grafted onto hydro-classification. Selective aggregation and dispersion of ultrafine particles are achieved through governing the interactions in the classification process. A series of laboratory classification tests for -44 pm kaolin have been conducted on a classification column. As a result, about 92 percent recovery for minus 2 pm size fraction Kaolin in the final product is obtained. In addition, two criteria for the classification are set up. Finally, a principle of classifying and controlling the interactions between particles is discussed in terms of surface thermodynamics and hydrodynamics.

Jan 1, 1995

By M. C. Roberts

The material composition of product is defined as the quantity of metal used per unit of product manufactured during a year. The material composition of product has shown steady and persistent declines over time for most metals and materials. This tendency demonstrates the continued improvements in manufacturing technology resulting from substitutions of other materials and increases in production efficiency. The purpose of this paper is to use the material composition of product to show the impact of advanced materials on the use of traditional metals.

Jan 1, 1992

By Yan. T. Y.

Uranium precipitation from an eluate using hydrogen peroxide has been studied in a laboratory continuous unit. The important process parameters were the dosage of H2O2, reaction pH and chloride ion concentration. In the process, the alkaline eluate is acidified to a pH of 2, then H2O2 at 110%-130% of the stoichiometric requirement is added, and finally NaOH is added to maintain a pH of 4 for one hour to complete the precipitation and settling. The chloride content in the system is controlled to 50g/L or below by rejecting part of the decant solution. The process has been successfully employed in commercial operations. The uranium recovery is complete, while the precipitate settles rapidly and can be processed to high purity yellow cake without filtration.

Jan 1, 1991

By M. R. Paterson, M. K. Suddaby

Operational and economic factors tend to favor the application of continuous processes in preference to batch processes in the majority of mineral processing applications. In this paper, the requirement for a continuous elution process is established and the development of a large-scale pilot plant is described. It is based on a continuous elution apparatus that has a number of special features. These are the subject of various patent applications. The apparatus is suitable for adaptation to the AARL, Zadra, and other methods of elution. The performance of the atmospheric continuous elution system (ACE) is concluded to have significant advantages over the batch process.

Jan 1, 1988

By S. K. Kawatra, T. C. Rao, J. P. Barnwal, Durga D. Patil

Coal macerals differ widely in their surface properties and in their hydrophobicities. Therefore, it is necessary to study the flotation time dependence of coal macerals using varying concentrations of various frothers and collectors. In the present study, froth flotation is used to explore the possibility of segregating coal macerals based on their relative rates of flotation. Petrographic analysis of the various macerals in the concentrate were carried out, and the results are expressed in terms of the recoveries of various maceral groups and mineral matter. Results show that it is possible to recover a good volume of the reactive macerals without mach loss of calorific value.

Jan 1, 2000

By R. V. Ramani, R. Natarajan, A. Bhattacherjee

Industries in general, and mining in particular, have become safer than ever before. However, there is a need to increase the search for the causes of mining work-related injuries and to contribute to their reduction, as required, through job redesign, work procedures and worker training. Mine accident and hazard control must be practiced in a manner consistent with the overall objectives of the mine management, which include the optimum allocation and effective utilization of the resources. The purposes of this paper are to: • present a set of analytical tools to analyze injury experience data. • apply these tools on a case study example, • discuss the results of the case study, and • identify the application limitations and the future research needs.

Jan 1, 1993

By J. W. Merks

Spreadsheet software is used to convert test results for drill core samples into borehole statistics such as volumes and masses of in-situ ore, metal contents and variances of metal contents. The properties of variances and the sampling variogram play a pivotal role, The additive of property of variances gives a sound scientific basis to the calculation of confidence limits for metal contents and grades as a measure of the risks associated with estimating reserves and resources.

Jan 1, 2000

By Lynn B. Hales, John A. Herbst, Thomas L. Gabardi

A system for a continuous determination of the charge volume of grinding media in ball mills and SAG mills has been developed. The system, comprised of a unique measurement device and a model based Kalman filter algorithm, determines grinding media level within a mill and calculates media and liner wear rates. The signal from an instrumented washer mounted on the exterior of the mill shell is used to provide the measurement that, along with mill power and on-line models for media mechanics, result in estimates of mill parameters that can be used in media addition control strategies. Data are presented for a 12.5 x 15 ft. ball mill.

Jan 1, 1990

By Ronald J. Allain

Water soluble polymers play an important role in many industries. The mining industry is dependent on these materials to help accomplish many solid-liquid (water) separations. Mechanical devices alone are not capable of achieving the degree of separation needed. Mechanical and chemical separations act in concert to accomplish the necessary separation. The history of the use of water soluble polymers has gone through several evolutionary phases and I believe we are facing another of these phases. At first, various natural products were common - starches, gums, and various polysaccharides. These were replaced by the synthetic polymers based on copolymerization of various vinylmonomers mainly in conjunction with acrylamide. The use of these polymers and their needs continues to grow. This paper will cover a brief overview followed by a look at the future of water soluble polymers. A focus will be on applications of water soluble polymers in the mining industry.

Jan 1, 1994

By Yongqin Zhang

A single bubble released into surfactant solution first accelerates, reaching a maximum velocity then decelerates to reach a terminal velocity. Modeling this "velocity profile" is fundamental to understanding the motion of bubbles in flotation systems. This contribution considers the terminal velocity. Modeling is by a combination of the Navier-Stokes equation for flow around the bubble and the Marangoni effect induced by surfactant on the bubble surface. Numerical simulation is shown to agree with experiment for bubbles in pure water and surfactant solutions.

Jan 1, 1999

By Dipak D. Shah, Sajjan K. Jain

An interceptor sewer, 2103 linear meters (6900 Ft), 1.52 meter (5 ft) in nominal diameter, is installed by a direct pipe jacking system utilizing a remotely controlled fully automatic slurry shield machine called "Unclemole". The system involves placement of custom designed fiberglass pipe with Unclemole. The sewer alignment is along a heavily travelled thoroughfare in Staten Island, New York with invert varying from 20 meters (65 ft) to 28 meters (92 ft) beneath the road surface, and passes through soils of Glacial and Cretaceous origin. Dewatering was carried out at the jacking and receiving pits. Details of ground conditions, the pipe jacking system and method, and tunneling experiences are herein described.

Jan 1, 1991

By Adam Feiler, John Ralston

Optical reflectometry was used to study the attachment and subsequent detachment of silica particles (diameter 25 nm) from the surface of titanium dioxide wafers under well-defined hydro- dynamic conditions. Atomic force microscopy was used to measure the interaction between silica spheres (diameter 7 pm) and titanium dioxide wafers under the same solution conditions. In addition to repulsive electrical double layer forces, adsorbed polyphosphates provide a short-ranged steric layer that reduces the lateral interaction between the surfaces. The use of these two complementary techniques has given valuable insight into the process responsible for fine particle detachment and has particular application to surface cleaning.

Jan 1, 2003

By David Jenkins

Grefco Inc. operates two diatomite mines in the western Santa Ynez Mountains. The larger of the two mines, the Palos Colorados Mine, is located approximately seven miles southeast of Lompoc. The Miguelito Mine is located about two miles south of Lompoc on the west side of the Miguelito Canyon. Diatomite from the Palos Colorados and Miguelito mines is trucked to the Grefco plant at Lompoc for processing (Figure 1). HISTORY Grefco, Inc. evolved from the originating Dicalite Company which in 1929 began operations at the Walteria plant in the Palos Verdes Hills south of Los Angeles. In 1942 Dicalite leased the Palos Colorados mine at Lompoc. In 1944 the Dicalite Company was purchased by Great Lakes Carbon Corporation.

Jan 1, 1995

By Daniel J. Kennedy, George W. Klinowski

A significant portion of each mine is ventilated with the help of auxiliary fans delivering fresh air to the faces of its developing headings via flexible or rigid ducts. Quality and volumes of air delivered to the blind working faces are essential for creation of safe and acceptable conditions for employed crews. Well designed and properly maintained delivery systems are necessary in each mine. The Cape Breton Coal Research Laboratory, part of the Canada Centre for Mineral and Energy Technology located in Sydney, Nova Scotia, Canada, developed a tracer gas based technique which provides fast and accurate evaluation of any auxiliary ventilation system performance. In addition, important information about the system's behaviour is gathered which can be used for designing a similar system in comparable conditions.

Jan 1, 1989

By Cherie M. Tilley

The Stillwater Mining Company has acquired a Tunnel Boring Machine to expedite the mine development operations at its Stillwater Mine. The machine purchased by Stillwater was previously owned by Melbourne Metropolitan Board of Works, Melbourne, Australia. The machine was manufactured by Robbins Co. of Kent, Washington. The Stillwater Mine has an extensive system of footwall laterals which are required by the mine development scheme. The initial mine plan called for in excess of 30,500 linear meters (100,000 linear feet) of footwall lateral drifts at a cross section of approximately 3.0 meters in width by 3.75 meters in height (10 feet x 12 feet). A Tunnel Boring Machine was selected for this work. The Robbins machine number is 146-193. This machine is approximately 4 meters (13 feet 5 inches) in diameter. The machine was modified extensively prior to commencing operation at the Stillwater Mine.

Jan 1, 1989

By Timothy N. Dunne, Joseph M. Gonzalez

This paper presents the case history of a comprehensive geotechnical investigation for the Crosstown Transport Facility, a 10,880 m long, 3.2 m diameter pressure tunnel proposed for construction in San Francisco, California. The proposed tunnel would be part of the City and County of San Francisco's Clean Water Program, and its purpose would be to convey stormwater and sewage from the east side of the City to the Pacific Ocean. Tunneling conditions were defined by surface geologic mapping, 94 exploratory borings, surface and borehole geophysics, aquifer testing, Goodman Jack testing, pressuremeter testing, and laboratory testing. Through the use of advanced coring techniques and a strictly controlled drilling fluid system, core recovery averaged 90 percent in the sheared and fractured rock of the Franciscan Formation. As a result, over 1,400 linear meters of rock core was recovered and is available for examination.

Jan 1, 1983

By R. J. Wesely, A. D. Zunkel, Tracy B. Braun, Philip L. LeHoux

An overview of gold processing operations at Barneys Canyon Mine is presented with particular emphasis on ore agglomerating experience, leaching and metallurgical accounting practices, and carbon column plant operating approach. The mine, located thirty kilometers from downtown Salt Lake City, is just eight kilometers north of the Bingham Canyon copper mine. Mining was initiated in February 1989 and the first gold was poured in September 1989. Through year-end 1992, approximately 7 million tonnes of ore have been processed and 12,000 kg of gold have been produced. Gold recovery is in excess of 85 percent.

Jan 1, 1993