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By D. Malhotra

This paper discusses the need for periodic auditing of mineral processing flowsheets and the potential benefits a company can gain from a study of this nature. A carefully designed flowsheet audit can have a significant impact on the metallurgical performance in the plant. Several case studies illustrating the potential benefits that can be attained from flowsheet auditing of mineral processing plants are discussed.

Jan 1, 1988

By W. Swisterski, G. Romaniszyn, S. A. Lukasiewicz

The present paper analyzes the motion of a particle of material in a horizontaly rotating tumbling mill. The sliding of the particle under action of dynamic and friction forces and its free flight fall are analyzed. It was found that mechanism of free-fall occurs at supercritical rotations of the mill.

Jan 1, 1991

By Paul G. Greenhill

The Australian Mineral Industries Research Association (AMIRA) was established by the Australian mineral industry in 1959 to develop and manage collaboratively funded research projects. Owned and managed by industry, it coordinates research that answers questions defined by the sponsoring companies of the projects. Now over 35 years old, the Association is an excellent example of what can be achieved through collaborative research and an industry - backed research organisation.

Jan 1, 2000

By David L. Gefvert

A general review of the role of cationic flotation reagents in the beneficiation of phosphate, iron, and potash ores. The three major types of cationic collectors-amines, ether amines, and condensates will be compared and contrasted. The effect of particle size, water chemistry, and water temperature on the choice of cationic flotation reagents for each industry will be discussed.

Jan 1, 1986

By Vanessa M. Torres, Renato S. Costa

This work presents the experience of Cia. Vale do Rio Doce in using Diagnostic Leaching tests to characterize refractory ores and CIP tailings. With the diagnostic leaching results of the highly refractory gold ore from Maria Preta Mine (Brazil), a process flowsheet was defined for a feasibility study of possible process modification on the existing plant. With CIP tailings from its Fazenda Brasileiro and Caué operations the amount of cyanidable gold was determined to aid plant optimization.

Jan 1, 1995

By Trevor J. Smith, Kevork A. Chouzadjian, Rob S. Burns, Steve J. Roden, Michelle A. Spieth

Investigations were undertaken to improve the recovery of silver from CRA's Hidden Valley gold/silver deposit by the addition of calcium peroxide. The addition of 0.75 to 1.5 kg/mt of calcium peroxide improved silver extraction by 5 - 300 and reduced cyanide consumption by up to 30%. Gold extraction was also marginally improved in some of the tests. The results are of economic interest and plant trials will be initiated once operations are underway.

Jan 1, 1990

By J. Muir

This report focuses on minimum ore block sizes that are economically feasible to mine with the vertical crater retreat (VCR) method. In 1985, Homestake Mining Co. began a program to bring several small block VCR stopes on line. This report examines these experimental stopes, including design parameters, ground control, drill patterns, secondary blasting, and mucking. Cost and scheduling comparisons are made with mechanized cut-and-fill and open cut- and-fill methods.

Jan 1, 1987

By John A. L. Campbell

Are safety concerns justified regarding the potential for a gas explosion due to recirculation when a scrubber is used on a continuous miner? The role of a respirable dust scrubber on a continuous miner section using blowing face ventilation is examined in this paper and the above question answered. Methane control using high efficiency scrubbers coupled with blowing face ventilation is promoted.

Jan 1, 1987

By L. B. Hales

Color video or digital cameras have been installed over flotation cells to monitor color, bubble size, froth movement, and other characteristics. These systems are designed so that the camera provides flotation performance information just as any other sensor might. Factorial tests have been run to monitor and measure the variation in froth characteristics as a function of flotation control settings. Ultimately, it is envisioned that froth image sensors can be used to monitor and control the flotation performance as effectively and for less cost than current analytical systems.

Jan 1, 1999

The American Mining Congress International Coal Show, this year’s largest gathering of coal industry leaders, convened May 5-8 in Chicago. Against a 73 000-m2 backdrop of the coal industry’s most productive equipment,* some 23 000 people heard government and industry executives give guardedly optimistic reports of coal’s near future gains. Although a rocky road lies ahead, operators and suppliers still continue their search to improve efficiency. Among the ideas discussed at the show were better underground communications systems, continuous on-line coal analysis, and recovery of hard-to-float coal.

Jan 7, 1980

By C. Villa Diniz, A. H. Martins, Fiona M. Doyle

It is proposed that battery grade MnO2 can be produced directly from a manganese ore from Azul Mine in Brazil, by leaching with HCI to remove heavy metals selectively. We are working to find a way of selectively separating Cu, Ni, Co, Pb and Fe from the resulting acidic manganese chloride solution, to detoxify it and produce marketable chloride solution. Chelating ion exchange resins are proving more promising for this separation than solvent extraction with commercially available reagents. Results from batch and column ion exchange tests that characterize the behavior of copper, nickel, cobalt, lead and iron are reported.

Jan 1, 1999

By Anthony J. Stewart, Jim W. Rosteck

This paper will discuss some of the equipment used to construct the middle segment of the MetroWest Water Supply Tunnel. The $252 million, seven-year project located in Framingham, Massachusetts consisted of two hard rock TBM drives worked from a single shaft. The 24,407-foot long west heading was constructed at the same time as the 35,006-foot long east heading. Also included was raise bore construction of four, 30-inch diameter steel lined riser shafts, one 12-foot finish and one 10-footfinish shaft as well as two major valve chambers. The main shaft was 400-feet deep and 32-foot diameter.

Jan 1, 2001

By John K. Kellis, Fazley Azhar

Advancements in AC drive technology offer conveyor designers a viable drive alternative for conveyor systems which require accurate load sharing as well as multiple drive systems. Recently developed AC drives have the ability to accurately control the output torque of AC motor. These AC drives, compared to current DC drives, offer superior performance characteristics while enjoying the benefits of an AC motor. Conveyor applications and case studies incorporating this AC drive technology are presented for review.

Jan 1, 1998

By J. A. Herbst, L. B. Hales, R. A. Ynchausti

Industrial application, theoretical discussion and technical research programs continue to stimulate acceptance of column flotation. Numerous authors have published model, parameter and application studies discussing advantages and problems which are associated with this minerals processing technique. This paper dispells the myth of the self-controlling column while focusing on the problems and opportunities which are inherent in the computer control of a column flotation cell.

Jan 1, 1988

By Muammer Kaya, Derya Oz

The main objective of this study was to remove printing ink from waste newspaper and improve the de-inked paper brightness as close as the unprinted paper by bleaching agents. This paper summarizes results of laboratory investigation into the de-inkability of newsprint printed with offset printing. Different chemicals and process parameters were varied to assess the effect on the brightness and cleanliness. The operations involved in de-inking process are briefly described and some of the problems being encountered are discussed.

Jan 1, 1995

By Rajive Ganguli

A control algorithm was developed previously for loading coal trains such that each car met customer specifications (Ganguli, 2001). In developing the algorithm, the effect of the variance of coal was not investigated. This paper explores the effect of the variability of coal on the algorithm using two approaches: theoretical analysis and simulation. Both approaches demonstrate that variance is not an issue when the customer quality specification is close to the mine average quality. However, when they are far apart, the performance of the algorithm improves with variance.

Jan 1, 2002

By Jorge Martinez

The Muck Valley Hydroelectric Project in Northeastern California required construction of a 3.65 meter tunnel through 6,623 meters of mixed volcanic flow deposits within a critical time frame. As Engineer and Construction Manager for the Project, Morrison-Knudsen Engineers invited bids for both Drill and Blast as well as Tunnel Boring Machine methods, selecting a contractor proposing a TBM designed and built specifically for this project which could excavate a wide variety of materials and maintain acceptable progress rates to complete the work within schedule. Tunnel lining as required included shotcrete with metal fibers and full circle concrete.

Jan 1, 1989

By Charles E. Mergentime, J. Marshall Dean

Mergentime/Loram's extension of the Washington, DC Metro Subway System includes construction of dual 1,770-foot tunnels in soft ground, a crossover structure, a fan structure and pumping station, and other related work. This paper describes the overall construction requirements of the Contract, including subsurface conditions; Mergentime's value engineering of the tunneling and compressed air contract requirement; selection of the tunnel boring machine and backup equipment; installation of the compressed air plant; the manufacture, use and evaluation of the tunnel liners; and the tunneling performances during construction of the first tunnel.

Jan 1, 1985

By J. Steven Whisler

Corporate managers are facing increasingly demanding challenges as they seek to ensure compliance with environmental laws. Management also must deal with new liabilities created by environmental laws. These laws provide both private groups and governmental agencies with access to the courts to seek penalties, compliance orders, cleanups, or to forestall developments that could affect ecosystems. Environmental laws and liabilities are also affecting commercial transactions, including the availability of financing. Corporate managers must develop new and innovative methods to address these challenges in order to assure both sustainable industrial growth and stewardship of the environment.

Jan 1, 1991

By R. Krishna, L. A. Kumar

The paper suggests a new empirical model for predicting mining subsidence. The parameters considered are Lithological Factor, which in this context meant percentage of sandstone, Rock Mass Factor (depending upon the RQD value of drill-hole cores), width: depth ratio and percentage extraction of coal. More than 250 drill-hole cores from seven longwall panels and 11 bord-and pillar (room-and-pillar) workings were analyzed from an extensive data bank of Singareni Collieries Company Ltd. (S.C.Co.), Andhra Pradesh, India. Excellent subsidence agreement was found with the suggested model.

Jan 1, 1993