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By P. R. G. Bak

The integration of interactive computer graphics technology with data analysis tools can assist in the evaluation of deposit models: the super- imposition of mine openings on complex geology can be quickly perceived using dynamic visualisation, colour-coding and transparency control while analysis functions assist in quantifying displayed information. To illustrate the functionality of such integration a research prototype system is presented which allows the interactive visualisation and evaluation of deposit models comprising both structural boundaries and the distribution of continuous properties.

Jan 1, 1992

By Maria C. Jaime

Optimization of the rock cutting performance plays a major role in the tunneling operation. For a given set of tool and cutting environment, rock fragments may be chipped away in numerous manners and it is crucial to understand and be able to predict the dynamics at the cutter-rock interface. This paper presents rational and realistic 3D finite element modeling of rock cutting where typical computational issues ?such as contact formulation, appropriate rock material response, mesh distortion, and crack propagation? are overcome. Cutting forces and failure mechanisms in this finite element analysis are successfully validated by laboratory single-cutter scratching tests in sandstone.

Jan 1, 2010

By Mathew B. Revell, Martyn L. Bloss

The paste fill system at BHP Cannington's underground silver-lead-zinc mine is described. The paste fill system has been operational since December 1997 and is the first of its type in Australia. Technical and operational learnings since stope filling commenced are presented. Topics described include plant performance, reticulation system design and construction, pipe wear and failure, rheology, in situ performance and laboratory testing.

Jan 1, 2001

By Vathsala Rajagopal, lwao lwasaki

The grinding media materials for the mining industry require corrosion and abrasion resistance properties not only to minimize the wear but also to improve the flotation recoveries of sulfide minerals. The media wear mechanisms and the factors influencing the grinding ball wear during grinding are discussed with respect to abrasion, corrosion and impact wear of grinding media materials. Interactions between the grinding media and sulfide minerals in a ball mill adversely affect the floatabilities of the ground minerals. The possible galvanic interactions between grinding medium-mineral and their effects on the flotation responses of sulfides are also reviewed. The selection criteria for alloy composition that reduces the overall wear along with adverse effects on flotation are brought out.

Jan 1, 1992

By Andrew Neale

ERIC GUTIERREZ: With that, we'll go ahead with the final speaker of the day, Andrew Neale. Andrew has a master's of science degree in mineral processing from the University of Alberta. He worked at the Falconbridge in Sudbury area, also at Brenda Mines, and then he became part of the Brenda Process Technology group in British Columbia. He joined Freeport in late 1993 in Indonesia, and was involved in process control and automation. He is now the senior manager of metallurgy in New Orleans. He's responsible for designing Freeport's new 100,000-ton-per-day expansion concentrator, which is currently being commissioned. Please welcome Andrew. ANDREW NEALE: With the ongoing explosion in digital computing power, there seems to be no limit to what can be modeled, simulated, and controlled in the mineral processing plant. However, at each stage of development of a control system, it is necessary to complete a cost-benefit analysis for justifying the move to a higher level of control. Incremental improvements in plant performance, while often significant, must be weighed against the costs of implementation and long-term maintenance. This presentation will provide examples of what the author believes are misplaced or misguided process control efforts and make a case for the KISS principle as applied to process control.

Jan 1, 1998

By Jack S. Watson, Rasika Nimkar, Robert M. Counce, BRADLEY BENNETT, Patrick Zhang

The purpose of this work is to develop a conceptual recovery process for thorium dioxide (ThO2) from its primary source, monazite. The study-level design presented in this paper represents an economically viable method for conducting ThO2 extraction from monazite ore while also recovering byproducts that include P2O5 and other rare earth element oxides rather than producing unnecessary waste streams. Three key points to note in the development of this process design are: (1) the process economics relied heavily on recovery of rare earth byproducts, (2) the thorium handling portions of the process could effectively be segregated from the rare earth and phosphate handling portions of the process, and (3) the thorium and uranium content in waste streams should be carefully managed and eliminated where possible.

By A. B. Samaddar

A prototype automated mapping and spatial information management system has been developed, and illustrates how a powerful map manipulation capability and a comprehensive display system can be combined using both raster and vector mapping: The concept of a mapbase and information retrieval mechanism, query language as well as text and graphical menus, is introduced. The Geographic Information System (GIS), which has been built around a system for storage and retrieval of spatial and textual data, allows interaction with geographic space represented on a displayed map. The prototype is demonstrated using maps and information of an open pit mine.

Jan 1, 1989

By P. James, L. J. Steiner, F. Turin

NIOSH researchers and an industry partner conducted an investigation to study the effectiveness of ergonomic interventions in mining. The study required a significant commitment of time and resources from the cooperating site, Bridger Coal Company. This paper focuses on some of the challenges faced by the researchers and their cooperator. Challenges included the need to redesign methods of identifying and prioritizing injuries, and the need to train the workforce in ergonomics while still maintaining progress and interest in the process. The authors discuss some practical interventions implemented by Bridger Coal to date, and discuss future research implications brought about by PacifiCorp’s Generation Business Unit, who monitored the project to determine whether an employee-owned ergonomic process could be implemented throughout their operations.

Jan 1, 2003

By M. A. Pipke, C. M. Brown

The semiautogemus grinding circuit at the Utah Mines Ltd., Island Copper operation, located on Vancouver Island, British Columbia, is described. Since startup of the operation in 1971, grinding circuit throughput has been progressively increased from the initial design rate of 90 000 (99,000) to the current average 45 000 t/d (49,600 stpd) of porphyry copper ore. Key developments ad modifications in operating and maintenance practice that have contributed to this increase are reviewed.

Jan 1, 1987

By E. Woodburn, R. Putman, A. L. Mular

Optimization strategies of possible interest to mineral processing are reviewed and typical strategies initiated in processing plants to date are discussed. Both On-Line and Off- Line optimization procedures have been employed by industry, assisted either by operators or by digital computers. In every case, dollar benefits have accrued.

Jan 1, 1976

By Curtis A. Pledger, H. Lee Wimmer, I. Michael Gowring

The Upper Diamond Fork Project, as part of the Central Utah Project Completion Act, conveys water six miles from the existing Sixth Water Aqueduct to the Diamond Fork Pipeline. During design, a Value Engineering team proposed a single-tunnel alignment that would be less destructive on the environment and might have a lower life cycle cost than the proposed design of two tunnels connected by two pipelines on steep hillsides. A decision was made to include this option in the bid process as a design-build alternative. The bid for this option was the lowest and a contract was awarded. During the TBM excavation a segment of tunnel wall caved in containing large quantities of water saturated with extremely high levels of hydrogen sul?de (H2S)gas (measured at 380 to 520 ppm in the air). The Central Utah Water Conservancy District (District) in consultation with Obayashi/Clyde (Contractor) quickly developed anew plan to finish the system by incorporating parts of the original tunnel/pipeline concept and re-bid the remainder of the project as a Phase 2 Design-Build contract.

Jan 1, 2003

By George D. Coumoulos

The following aspects of diasporic bauxite are discussed: The importance of world reserves of diasporic bauxites; the geological, chemical and mineralogical characteristics of the Greek diasporic bauxite; the uniformity of bauxite deliveries; the significance of the absence of organics; the excellent settling properties of the red mud; the production of sandy alumina from diasporic bauxites; the advantages of applying tube digestion systems in processing diasporic bauxites; the conditions for introducing diasporic bauxite in the existing European refineries.

Jan 1, 1984

By Andrew T. MacKenzie, Paul A. Rantala

Predictive pastefill rheology (flow characteristic), models have long challenged pastefill practitioners. While the methodology and practicality of recipe formulation is attainable in most locals, the remaining challenge has been to devise a predictive mathematical or empirical model of paste flow characteristics. Flow phenomenon can now be assigned mathematical and physical basis. The authors herein disclose physical and mathematical methods that demonstrate how operators could proceed when designing reliable pastefill systems. Knowledge presented will allow users flexibility in adjusting flow-rates. Laboratory data shows stiff pastefill delivery design can be derived through mathematical relationships of particle size, material characteristics and pipe diameter.

Jan 1, 2001

By K. L. Myers, R. Espell, C. Deringer

Construction of the AA Pad reclamation was completed in the fall of 2000. Seeding of the ET cover began in the late fall of 2000 and continued through May of 2001. On Saturday afternoon, June 1, 2002, a large, very localized thunderstorm struck the reclaimed AA Pad site. Eyewitnesses present at the time described a dark storm cloud parked above the site for less than half an hour. Average rainfall intensity was measured to be 122 mm (4.8 inches) per hour and peak rainfall intensity was estimated to be 213 mm (8.4 inches) to 259 mm(10.2 inches) per hour. At the time of the storm, the construction was less than two (2) years old and the vegetation had only a single season of growth. The entire period from the end of construction until the date of the storm was a drought period with below normal precipitation. Other than a few small snowmelt events, there was no precipitation event large enough to produce any significant flow in the channel network. Therefore, the very first significant runoff event was the extreme event of June 1, 2002. The storm essentially represents a large-scale field test of the design concepts used at the AA Pad site. Shortly after the storm, data was collected and analyzed with the intent of learning as much as possible about the performance of the cover system design with the expectation that the newly acquired knowledge might be utilized in future designs to further improve the performance of similar cover systems during extreme events.

Jan 1, 2003

By Ernst Langer

INTRODUCTION Morro do Niquel is located near the small town of Pratdáolis in the southwest part of the State of Minas Gerais, Brazil, about 300 km in a straight line north of São Paulo and 300 krn west of Belo Horizonte. The deposit is known since 1935. Systematic exploration started, however, only in 1957 and production with one furnace in 1962. Since 1969, after the installation of a second furnace, the mine produces about 2 500 tons of nickel, contained in ferronickel, per year. This production is now consumed totally by the Brazilian steel industry. The "Morro do Niquel" is a serpentinite stock of 900 by 400 m which rises 200 m high above the surrounding metamorphic rocks of Algokian age (see Figure 1). On top of the hill there is a leached barren zone of about 200 by 400 m, generally 20-30 m deep, which consists practically only of a boxwork of quartz colored brown by limonite. Surrounding this zone on the sides of the hill is weathered, decomposed serpentinite which contains about 213 of the economic nickel mineralization. Roughly 113 of the ore reserves lie below the leached overburden representing ore of a different type. The geological map and cross-section, Figure 2, give a clear picture of the occurrence.

Jan 1, 1979

By R. K. Davey

Before the introduction of computerized procedures, mineralization modeling (compilation of level maps), ultimate pit studies, ore reserve compilations, and long-range mine planning all were performed manually. In fact, much of the basis for today's computer programs was derived from manual procedures and actual experience of mining engineers and geologists.

Jan 1, 1979

By Frederick T. Graybeal

Silver Bell is located about 56 km (35 miles) northwest of Tucson, AZ. It is a classic porphyry copper deposit containing enriched disseminated chalcocite ore in altered porphyritic rocks with chalcopyrite in adjacent skarn zones. The discovery of Silver Bell was an evolutionary process that occurred over a 75-year period. Recorded mining activity began about 1865 on Boot Hill east of El Tiro pit (see Fig. 1) where outcrops of altered limestones were found to contain 425 to 482 g (15 to 17 oz) Ag mixed with copper oxides. By 1874, the Young America Copper Co. was mining shallow occurrences of 30% Cu along the north side of the present Oxide pit. The ore was shipped by wagon to Yuma, AZ, and then by boat to San Francisco for smelting. By 1881, the district supported several mining companies, two small smelters, and was being favorably compared to Bisbee in local newspapers. Most of the ore mined in the period 1865-1903 came from pods of massive sulfide or their oxidized products which were distributed in an unpredictable fashion through a large skarn zone in Paleozoic limestone east of El Tiro pit. Ore grades varied from 5 to 10% Cu.

Jan 1, 1991

By Leon J. Jacobs, Kyle R. Ott

This paper discusses design and construction aspects of the tunnel, shaft and station for the Weehawken Tunnel and Bergen line Avenue Station. The project consists of a 1,269 m (4,156 ft) long existing railroad tunnel, which will be enlarged and equipped with a two-track light rail system. The project also includes construction of a deep underground station, with a large shaft connecting the surface station to the below ground station for access and ventilation purposes. Vibration and noise from blasting is a critical community issue and blasting adjacent to two 230-kV duct banks located in the tunnel invert required special blasting procedures.

Jan 1, 2003

By Gunnar Nord

Shifting ground conditions when tunnelling often call for different methods of attacking the tunnel face. In order to overcome problems with local unstable soft ground in a hard rock tunnelling project the Boodex method offers a cost effective alternative. Boodex and variants of it is a combination of two well-known techniques, drilling with Boomer rig using Odex gear. It will give a steel lined hole ready for grouting and the steel pipe has a load bearing capacity that means that a spiling effect is achieved. In this paper the method and some applications will be described with possibilities and limitations.

Jan 1, 2003

By H. Barry Holt, Charles A. Bischoff

On November 15, 1990, President Bush signed the Clean Air Act Amendments of 1990. The new legislation is sweeping in its demands for cuts in smog, acid deposition, toxic air pollutants and ozone-depleting chemicals. The Amendments will siqnificantly alter air quality permitting and compliance and are estimted to cost billions of dollars to implement. This article provides an overview and summary of each of the eleven titles of the Amendments. It also addresses how the Amendments will be implemented.

Jan 1, 1991