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By Frank Matter

Production of ultrafine powders of industrial minerals has been a problem in the past. In recent years new wet and dry grinding stirred ball mill systems have emerged which have been commercialized Two such systems are the TRZK mill with double step air classifier for dry grinding and the NRZK mill for wet grinding The primary features of these mills are feed entering from top and the product along with the grinding media leaving from the bottom, and a media separation and recycle system A detailed description of the NRZK mill for grinding coal is presented

Jan 1, 1983

By James R. Aggson, Verne E. Hooker, Dennis R. Dolinar

The stability of underground openings and mining systems is closely related to the in situ stress field. This paper presents a short discussion of the three-component borehole deformation gage and overcoring technique which the Bureau of Mines uses to measure in situ stresses, and a summary of stress data that the Bureau has gathered in the process of evaluating ground control problems. Specific ground control problems and stress distributions are discussed as examples.

Jan 1, 1982

By Boris V. Vlasenko, Vadim P. Potapov, Gennady I. Gritsko

In this paper we consider the elements of an information geomechanic monitoring system which is used in computerized mine planning and mining operations control. The automated sys tem is a technical means of geomechanic monitoring, as a complex system of regulated observations, estimation and prediction of changes in geomechanic state of rock mass and workings during underground mining of coal deposits. Geomechanic monitoring at coal mines and the automated system execute data collection, analysis and calculations of geomechanic situation in the panel during planning, development and carrying-out of mining operations for ensuring geotechnical stability of underground mining.

Jan 1, 1996

By J. Stachurski, N. A. Abdel-Khalek

Flotation tests were carried out on six coal samples of different rank as well as their oxidized samples. A mixture of diesel oil and alcohols was used in these tests. Surface oxidation caused a distinct decrease during flotation recovery with some improvement in the grade. The reduction in the recovery increased with increasing concentration of the oxidizing agent. The floatability of low rank coals was affected by oxidation to a higher degree than the floatability of medium and high rank coals. The recovery-size curves of oxidized samples were similar in shape to the recovery-size curves of non-oxidized coals.

Jan 1, 1991

By M. Stefanakis

Respect for the people is one of the main values of S&B. Such respect needs to be manifested by actions ensuring the bodily and spiritual integrity of personnel in pursuing their work. The ultimate target is to achieve zero accidents by developing the culture and infrastructure required to support it. Within this framework, the following proactive safety practices were introduced in 2004 and are implemented at S&B Greek sites: (a.) Management Safety Visits (MSVs) of shop floor operations to address safety attributes of work guidelines, (b.) Monitoring compliance with critical work guidelines, using a ?safety barometer? tool. The proactive nature of both above systems, facilitates communication with employees on safety behaviors and their adoption in our facilities at Milos and Fokis, has been successful. Above all, these practices corroborate the management?s concern for the people and its commitment to continuously improve the working environment.

Jan 1, 2007

By Ch. Arvanitidis

This work concentrates on investigating the development of a geotechnical classification method for the Greek soils, which can readily provide a rough but usable estimate of the main strength parameters of the soil. It is expected that such a system will be useful to the structural engineer for either checking the laboratory results or for providing a direct estimate in cases where no tests have been conducted. The method provides strength parameter values by relating classification or physical parameters of various types of soils and/or in situ observations of geological and physiographical nature to the strength parameters, such as, cohesion, angle of internal friction, compressibility, modulus of elasticity, etc, by means of a statistical approach and the extraction of empirical formulae.

Jan 1, 2006

By S. Behl, Pradip

Selective-flocculation process development generally involves single-mineral flocculation tests to identify the appropriate polymer experimental conditions for achieving the desired selectivity. Invariably the selectivity predicted on the basis of such tests is not realized when mixed-mineral tests are conducted. A systematic experimental investigation revealed that adsorption of the polymer on various substrates is critical to selecting the suitable flocculant. Simultaneously, a mathematical model was developed to predict the overall process of efficiency with a given polymer. In this paper, the results of these efforts to scientifically design a suitable selective flocculation process are presented.

Jan 1, 1994

By Lewis Gordon, Alan Morrow, Aundra Nix

At the ASARCO Mission Mill, a multivariable, predictive controller was used to optimize parallel grinding circuits, improving throughput and product size. Using a dynamic model of the grinding circuit developed from on-line testing the software manipulates 4 variables to control 14 quality and constraint variables in each circuit. Traditionally, model-based control in grinding is difficult due to ore changes. This is addressed via a novel method to predict mill overload and automatic model switching.

Jan 1, 2000

By Dan Kump

This paper provides an overview of Barrick Gold's Bullfrog underground mine backfill program. The Bullfrog underground mine was a gold mine that primarily used the underhand cut-and-fill mining method. The first portal was established June 18, 1991, and mining continued until Dec. 29, 1998. This paper begins with a discussion of the events that took place to reach about 1.8 kt/d (2,000 stpd) of backfill. It ends with a commentary of what was learned. The Bullfrog experience suggests that there are two essential factors to a successful backfill program: a well-graded aggregate supply and proper placing procedures.

Jan 1, 2002

By Jim Armbrust

JAMIE DAVIS: Our next speaker is Jim Armbrust, maintenance manager at Phelps Dodge, Morenci. Jim's presentation is titled "We Need More Training-How to Get the Biggest Bang for the Buck." We've talked a lot about preventative maintenance and we've heard several people talk about training. How do we train to use all these systems? How do we educate people? This will be a nice little wrap-up for us. JIM ARMBRUST: One common theme from this morning's talk is that we need more training. That's exactly what we'll be talking about for the next few minutes.

Jan 1, 1998

By S. Stewart

The topic of sustainability in the mining and minerals industries focusing on economic development, ecological integrity and responsible stewardship of the environment together with community well being are vital issues for our industries at a crucial time in our history. Many of the priorities of the Greek Presidency of the European Community ? Sharing the Future in a Community of Values ? encourage our industry to continue to innovate and develop many of the environmental and social initiatives already underway. Sustainable development is here to stay and has been placed strategically at the heart of all European public policy. The future of the minerals industry here in Europe as well as elsewhere depends on how well professional mining people, both as individuals and through their associations and others, have to present their case for a sustainable mining and minerals industry to a critical world. And, Greece with its strong and expanding mining, minerals and metals base has more to win or lose from this endeavor than many others.

Jan 1, 2003

By J. W. Oberholzer

Problems with gravimetric sampling have led to the establishing of a computer linked tyndallometer dust measuring system. Preliminary tests conducted with the system indicate that the system can be used to do correlative exercises between mining activities and dust levels. The system also allows occurrence characteristics of dust levels to be determined. Use of this equipment will enable dust allaying methods to be tailored to the specific underground situation.

Jan 1, 1987

By Margaret Armstrong, Arne Berckmans

The longterm aim of this research project is to find fast ways of simulating the recoverable reserves of a deposit for input into financial Monte Carlo simulations without having to conditionally simulate the whole orebody many times. The first step in this re- search is to visualize and quantify the ore tonnage T and the metal quantity Q above an arbitrary cutoff z. This paper presents detailed results for one specific distribution, the lognormal. These lead to a suggestion of a fast way of simulating QTz curves.

Jan 1, 1996

By Li Honggui, Liu Maosheng, Zhao Zhongwei, Sun Peimci, Li Yunjiao

Leaching of Shizhuyuan low-grade refractory tungsten ore was carried out in a mechanically activating reactor. The effect of experimental parameters-temperature, amount of Na2C03, addition of NaOH, ratio of liquid to solid and leaching time - on the recovery of WO3 was studied. The WO3 recovery up to 96.99% have been achieved when the tungsten ore was digested by soda not more than three times the stoichiometric amount at 185-195°C for 1 .O-2.0 hours. Iso-extraction countour diagrams were drawn to illustrate the effect of various parameters on leaching. The WO3 recovery could be expected to increase 10-15% compared to that of conventional soda autoclave process.

Jan 1, 1995

By Jack G. Pippenger

This report focuses on the procedures required to review, prepare specifications, bid, and purchase a fully integrated computer system for utilization by engineering personnel in all phases of mine engineering. The presentation is based on the experiences encountered in 1984 in procuring an engineering computer system at The North American Coal Corporation's Western Divi- sion. A two-phase report detailing the purchasing process and subsequent utilization of the engineering computer system will be given. Special detail is also provided on the final system hardware and software setup.

Jan 1, 1989

By J. Searls

The potash review arrived too late to appear in the June issue. Potash is a general term that includes several water soluble potassium salts: potassium chloride (muriate of potash), potassium sulfate (sulfate of potash), potassium magnesium sulfate (sulfate of potash-magnesia), potassium nitrate (niter) and sometimes potassium carbonate. Potassium carbonate was the original potash when it was leached from wood ashes and dried in large, cast iron pots to black-to-gray crystals (ash) to form "pot ash." "Pearlash" was potash roasted to white crystals. In modern terminology, the great preponderance of "potash" is the mined forms. It is estimated that 95% of the potash mined around the world is used as fertilizer. In 1840, Justus von Liebig demonstrated to the scientific community the importance of potassium to the growth of plants. But there was no low-priced source of potash available at that time. In the winter of 1851-1852, minable potash was discovered near Stassfurt,

Jan 1, 1991

By Lee Herold Storey

Groundwater remediation is growing in occurrence in the western United States. Groundwater remediation programs are regulated by state water quality statutes. The remedial action plans implemented under these statutes may conflict with well-established existing rights to withdraw groundwater for beneficial use. This paper discusses how the states of Arizona, Colorado and New Mexico administer conflicts between the need to withdraw and remediate groundwater with the existing rights of others to withdraw groundwater for beneficial purposes.

Jan 1, 1991

By Charles H. Arnold, Timothy Fallara, David A. Day, Paul H. Marshall

The Upper Scioto West Interceptor Sewer (USWIS), Parts 1 and 2, consists of approximately 7,128 meters (23,385 ft) of 328 cm (129 in.) diameter tunnel. The project ex-tends from the City of Dublin to Griggs Dam in the City of Columbus. The majority of the tunnel was designed for excavation in rock by TBM. The remaining portions span pre-glaciation formed valleys in-filled with glacially-derived sediments. Tunnel construction in one of the glacial till filled sections includes excavation by drilling and controlled blasting. The other section will be constructed by ground consolidation followed by excavation by TBM. This paper describes the methods employed to mine the glacial till filled valleys.

Jan 1, 1997

By Karen L. Menna

At Digital Equipment Corporation, increasing demands on executive secretaries to share, track, and retrieve information prompted development of ALL-IN-1 System for Executive Services. Executive secretaries asked engineers to combine word processing and electronic mail with utilities for managing time; logging and tracking telephone calls, letters, and inquires; creating presentations; compiling directories; and archiving. The system, two years in development, now automates the president's and senior vice presidents? offices at Digital. It allows secretaries to interrupt any task with two keystrokes, and return later to the original task. The system has speeded customer response, enabled online information sharing, and increased professionalism and customer satisfaction.

Jan 1, 1989

By George Verley

A new and important task in assisting developing countries is the transfer of microcomputer technology applied to mineral exploration and mining. With this objective in mind, three micro- computers have been introduced in Niger and a training program has been put into place. The core of the program consists of two seminars in Niamey, Niger, after which the attendants will be able to operate a microcomputer and use a small library of application software.

Jan 1, 1987