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By R. Pothina

The objective of this research was to develop a mathematical model for gyratory crushers to help in the prediction of energy consumption and to analyze dominant parameters that affect this energy consumption. The development of a gyratory crusher model was achieved in the following three main stages: mathematical representation and coding of the crushing process; building an amperage constant model to derive an energy-scaling formula; and modifying the amperage constant model to represent a full-scale model. Due to their significant influence on feed-size distributions, two blasting parameters, i.e., burden and spacing, were considered. The crusher parameters that affect energy consumption were also identified. A case study of an operating dolomite mine was performed. The results indicated that by changing the burden, spacing and crusher closed-side setting, the overall (blasting and crushing) costs could be reduced by 4.7% to 7.9% annually. It can also be concluded that burden and spacing values have a linear positive relationship with the crusher energy consumption, while closed-side setting values have an inverse linear relationship with the energy consumption.

Jan 1, 2007

By H. A. Oliveira, A. Azevedo

Physical and chemical characterization and solid/liquid separation of turbid waters from a river affected by an iron tailing rupture disaster (Gualaxo do Norte River, Brazil) were studied at bench scale. Parameters such as turbidity, pH, surface tension, electrical conductivity, total suspended solids (TSS), particle size distribution (micro- and nanoparticles), and zeta potential were analyzed from samples collected at three different river depths. The results in all samples showed the presence of micro- and nanoparticles, ranging in diameters from 100 nm to 200 μm. Best results for flocculation and settling were obtained at pH 7.5, through an innovative combination of eco-friendly reagents: (i) ferric hydroxide precipitates (10 mg L−1 Fe3+) to sweep (enmesh) the dispersed solids and (ii) gelatinized starch (5 mg L−1 ) to form large flocs. The results showed removals between 90 and 100% of total suspended solids (micro- and nanoparticles), resulting in clear water with residual turbidity < 7 NTU. It is believed that this innovative alternative has a high potential for flocculating and treating the turbid water at Gualaxo do Norte River, assisting the water treatment stations.

By H. A. Oliveira, A. Azevedo

Physical and chemical characterization and solid/liquid separation of turbid waters from a river affected by an iron tailing rupture disaster (Gualaxo do Norte River, Brazil) were studied at bench scale. Parameters such as turbidity, pH, surface tension, electrical conductivity, total suspended solids (TSS), particle size distribution (micro- and nanoparticles), and zeta potential were analyzed from samples collected at three different river depths. The results in all samples showed the presence of micro- and nanoparticles, ranging in diameters from 100 nm to 200 μm. Best results for flocculation and settling were obtained at pH 7.5, through an innovative combination of eco-friendly reagents: (i) ferric hydroxide precipitates (10 mg L−1 Fe3+) to sweep (enmesh) the dispersed solids and (ii) gelatinized starch (5 mg L−1 ) to form large flocs. The results showed removals between 90 and 100% of total suspended solids (micro- and nanoparticles), resulting in clear water with residual turbidity < 7 NTU. It is believed that this innovative alternative has a high potential for flocculating and treating the turbid water at Gualaxo do Norte River, assisting the water treatment stations.

By D. Drymonitis, G. Gialoglou

"Placer gold mineralizations have been observed in the north-eastern parts of Greece. Some of them have been at first evaluated to be of special interest so, exploration campaigns have been designed and carried out. Among the other exploration techniques applied on the sites of interest, drilling was the one to give the detailed information and data for the evaluation of the deposits. Having collected the data from trenching and two consecutive drilling campaigns, they were processed geostatistically to estimate the ore reserves and therefore the economic interest of the deposits. The latter was done by using exploitability indices, which would give a rough idea whether the deposits were economically feasible. A small number of such deposits have been spotted in the area and have been explored and evaluated as above. The present paper deals with the most important of them, giving all the process followed and the results derived from the exploration carried out."

Jan 1, 2005

By G. Coombs, L. Meade, J. Welshimer

Industrial Minerals commodity profiles are continued from May&apos;s Annual Review issue. Diatomite G. Coombs, Manville Sales Corp. Growth in US diatomite production continued to lag in 1986. The US Bureau of Mines estimated that 580 kt (640,000 st) were produced last year. This is a 1%0 growth over 1985. The cumulative growth from the 1982 low point is 4.4%. Present production, though, is still only 90% of the high tonnage of 1979. The industry will see increased competitive activity with the start-ups of two new mines and production facilities in California and Oregon. US production has come primarily from Lompoc, CA, Bassalt, Clark Station, and Lovelock, NV, and Quincy, WA. New production, probably with capacities of 45 kt/a (50,000 stpy) each, have started near Burney, CA, and Vale, OR. Eagle Picher&apos;s new, full-line filter aid and filler plant at Celatom, Vale, OR, was dedicated in August. The plant uses diatomite from the Celatom mining district in Juntura, OR. Grefco&apos;s new filter aid and filler plant near Burney, CA, was ready in July. It produced flux calcined products through a single kiln and can handle both bag and bulk shipments. The operations are in Shata County with the plant and mine at the same site. Manville Specialties Group is moving its Filtration and Minerals Division headquarters and research staffs to Lompoc, CA. The move is intended to strengthen response and performance by locating research, marketing, and production close together. Diatomite is processed in three methods: natural, calcined, and flux calcined. The natural is dried to remove water and is particle size classified. Calcined or straight calcined products have been sintered to modify particle size or permeability. Flux calcination, or flux sintering, has a stronger influence on permeability and also benefits color. The unique structure of diatomite is used in a range of particle sizes from fine paint fillers, to coarser filter aids, to granular aggregates. Dimension stone L. Meade, Geomapping Associates Ltd. 1986 was another good year for dimension stone production. The trend toward using marble, granite, limestone, sandstone, and slate has created an increasing demand. According to US Bureau of Mines 1986 estimates, 1.1 Mt (1.2 million st) of dimension stone, with a value of $173 million, was produced by 200 companies. This is an increase from 1985, where 220 companies produced 1 Mt (1.12 million st) valued at $172 million. The increased production volume and decreased unit value is due to the competition from imports. The net import reliance in 1986 was 68% compared to 62% in 1985. The value of imports was $374 million in 1986 versus $295 million the year before. In an effort to maintain their market share, domestic finishers, particularly in the granite industry, continued to upgrade plants and machinery during 1986. In addition, offshore dollars have financed a number of fabricating facilities in North America that will finish imported rough stock. It is hoped that this increased domestic production capability will capitalize on a devalued US dollar. The trend has been for growth in stone usage and market. This trend is continuing with increased public awareness and desire for natural stone in buildings. The area of greatest market growth is expected to be in residential and interior decorative stone usage. Use of sophisticated, automated equipment has made the cost more affordable. Now lobbies, foyers, and specialty rooms are being clad in stone. Dolomite J. Welshimer, National Lime & Stone Co. About three-quarters of dolomite production is used as construction aggregates and 10% to 20% is sold or used as an industrial mineral. Total limestone and dolomite consumed for chemical and metallurgical purposes is about 136 Mt/a (150 million stpy). Sales of industrial dolomitic products were somewhat stronger in 1986 than levels recorded in the early 1980s. Some of the sales&apos; strength, however, can be attributed to reductions in the number of active mining and processing operations. The industry will probably undergo further consolidation by the end of this decade. This will be due primarily to the continued softening in demand by the steel industry. Dolomitic limestone deposits being mined for raw materials for the steel, glass, and refractory in¬dustries are generally 54% calcium carbonate and 45% magnesium carbonate by weight. Impurities composed of silicon, aluminum, iron, sulfur, and phosphorous, represent less than 1%. The heaviest concentration of high purity, surface mineable dolomite in the US is in northwestern Ohio. Crushed and sized dolomitic limestone is a basic raw material for the iron and steel industry. It is also used as feed stone or lime kilns. Soft-burned lime is a popular raw material for BOF steel production. It is also used extensively in insulating glass fiber manufacturing. A related material, hydrated

Jan 6, 1987

By D. Olsen, S. Cole, J. Strid, G. Colzani

This paper focuses on the underground tunnel work at the Hollywood Water Quality Improvement Project (HWQIP) in Los Angeles, CA. The HWQIP is being constructed to provide a water distribution system to bypass the existing Hollywood Reservoir System, which supplies drinking water for 500,000 people. The major project features include, a 2.9-meter diameter 1,829 meter long bypass tunnel, a 1.8-meterdiameter 366 meter long utility tunnel, 3 jack and bore tunnels, two 136 million liters underground circumferentially wrapped pre-stressed concrete water storage tanks, associated piping, and mechanical facilities. The physical project location coupled with strong community involvement and stringent environmental concerns was a considerable driving force for this project located in the Cahuenga Pass area of the Hollywood Hills north of Los Angeles, CA.

Jan 1, 2001

By E. Z. Manos

The Detroit salt mine is operated by the Detroit Salt Co. It is one of the oldest underground room-and-pillar mines in the United States still in production. Mining at the Detroit salt mine began in 1906 with the sinking of the No. 1 shaft. Mining continued through the years, becoming progressively more modern in its equipment and techniques, until it was closed in 1983. In 1997, after a period of care and maintenance, the newly formed Detroit Salt Co. decided to reopen the mine. Upon completion of an extensive rehabilitation program, salt production resumed in 1998. Production currently continues at a rate of 910kt/a (1 million stpy). To date, the Detroit salt mine has mined more than 45 Mt (50 million st).This mine is unique because it lies under a heavily urbanized area within metropolitan Detroit. The mine and its history make a good case study for the continuing coexistence between the mining industry and its environs.

Jan 1, 2003

By Descour Jozef, Suguru Shirasagi, Takuji Yamamoto, Koji Murakami

For TBM tunneling no visual inspection of excavated ground is possible. This may hinder the high-speed excavation, particularly in complex ground conditions. The TBM Excavation Control System was developed for better prediction of geological conditions ahead of the tunnel face during excavation. The seismic reflector tracing produces volumetric images of anomalies in the ground in “near-real time.” These images are verified using logging data from pilot boring and TBM driving data, to improve reliability and precision of ground mapping. Also good correlation was obtained between the rock strength index computed from TBM data, and one derived from volumetric seismic images.

Jan 1, 2007

Introduction The Homestake Mining Co. has always been big on gold. After 108 years in the business, the company and its principal product are almost synonymous. The relationship continues. On Sept. 28, 1985, Homestake held formal dedication ceremonies for its newest gold mine - McLaughlin. The McLaughlin open-pit operation is located in northern California, some 113 km (70 miles) northeast of San Francisco. It lies near the boundaries of three counties - Napa, Yolo, and Lake - and a portion of its facilities are located in each. McLaughlin was originally the site of the Manhattan mercury mine that produced nearly 80,000 flasks of the quicksilver from the 1860s to 1978. At the September dedication, Homestake renamed the mine in honor of the late Donald H. McLaughlin. McLaughlin was with Homestake for nearly 60 years. He rose from exploration geologist to his ultimate positions of chief executive officer, director, chairman of the board of directors, chairman emeritus, and chairman of the executive committee. The discovery of the McLaughlin deposit occurred in 1978, the last year of operation for the Manhattan mine. Homestake geologists used a newly developed model and found surface gold at the mine site. That same year, Homestake signed an agreement with the property owner and began a two-and-a-half year exploration program. An initial discovery announcement of 31.1 t (1 million oz) of gold was made in 1980. In 1981, this was revised to 93.3 t (3 million oz), or 18 Mt (20 million st) of ore grading 5.2 g/t (0.152 oz per st). Expected mine life is 20 years. Construction began in September 1983, following the issuance of stage one permits. Start-up of operations took place in early 1985 and the first gold-silver dore bar was poured on March 4. Since then, more than 540 kt (600,000 st) of ore has been milled, producing about 1.6 t (50,000 oz) of gold. Of special interest at McLaughlin is the use of three autoclaves for gold extraction. According to Homestake, this is a first. The autoclaves are designed for a 90% gold recovery rate. Early results have proven yields at this rate and higher. Geology The McLaughlin deposit is about 1.5 km (5000 ft) long. It occurs as a wedge-shape, narrowing to a verti-

Jan 1, 1986

Coal preparation plant simulators are used to study flowsheet alternatives and determine product quality and quantity that can be produced under various operating conditions for individual circuits. Some simulators also provide an estimate of the cost per ton of clean coal by determining the number and size of different processing units required for a specific raw coal tonnage and by computing both capital and operating costs for individual units. However, to the authors? knowledge, none of these simulators have the ability to optimize plant performance while satisfying multiple product quality constraints and selecting the most profitable flowsheet from many alternatives. A novel coal preparation plant simulator (SIU-Sim) that maximizes the overall plant yield using a robust optimization tool and selects the best plant cleaning circuit configuration based on maximum plant profitability is presented. The simulator also identifies the best operating conditions for individual circuits of a plant to satisfy multiple quality constraints for the overall clean coal product. It uses a genetic algorithms- (GA) based technique to maximize the overall plant yield for each cleaning flowsheet alternative and uses a net present value (NPV) analysis technique to maximize plant profitability for the entire life of a new plant or the remaining life of an existing plant. The step-by-step development of the simulator along with a case study demonstrating its specific features is presented.

Jan 1, 2008

By B. Burke, R. Colquhoun, K. Thomas, R. Walton, D. Fentie

The new Roasting Facility at Barrick’s Goldstrike Mine in Nevada, U.S.A. was developed to process 12,000 tons per day of refractory gold ore. The process consists of crushing, dry grinding, roasting, extensive gas purification, calcine quenching and leaching in the presence of activated carbon. The new plant is integrated into the existing Goldstrike facility, treating ore from both open pit and underground sources. The process design, procurement, construction and commissioning of the Roaster facility was performed successfully over a 3½ year period with peaks of 400 engineering personnel and 950 construction personnel supporting the project. The US$330,000,000 project was completed ahead of schedule and under budget. The commissioning was well planned and proceeded smoothly through a rapid start-up to achieve all primary goals within three months of the start of processing of ore.

Jan 1, 2001

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept. 13, 2008 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. This will be the 21st Annual National Mining Museum and Induction Banquet. The four inductees are Lew Eklund, 76, Carrie Jane Billings Everson (1843-1914), ?Colonel? William C. Greene (1851-1911) and Arthur L. Hawkesworth (1860-1905). Lew Eklund founded Eklund Drilling that is now based in Elko, NV. He invented many designs that play a major role in today?s mining industry. His Cyclo Blower and various sampling devices he designed helped to revolutionize gold deposit exploration by allowing mining companies to effectively sample microscopic gold. Carrie Jane Billings Everson discovered and proved a method for bulk oil flotation concentration of mineral ores, the precursor to modern froth flotation methods of minerals concentration. She patented her process in 1886. In the early 1890s, coworkers built and operated demonstration plants incorporating her bulk oil flotation process. ?Colonel? William C. Greene was responsible for the development of the great copper mining properties of Cananea, Mexico. In seven years, he went from ragged cattleman and adventurer to the greatest captain of industry the borderlands have ever seen. Arthur L. Hawkesworth was a master mechanic for Anaconda Copper. He invented the detachable drill bit. His invention generated tremendous savings for the mining industry in time, in dollars and in safer operating conditions underground. His bit?s long lasting contribution to improved mine economics is immeasurable. The 21st Annual National Mining Museum and Induction Banquet will begin with an open house and reception at 5:30 p.m. followed by the dinner and program at 7 p.m. The inductions will bring to 201 the number of mining ?greats? whose engraved photographs and biographical sketches are installed in the National Mining Hall of Fame.

Jan 1, 2008

By A. Eftimie, M. Stanley

The World Bank Group (WBG) believes that extractive industries can make significant contribution to sustainable development and poverty reduction, providing that environmental, social, and corporate governance issues are properly managed. The WBG recognizes that stakeholders have legitimate concerns about the impact of extractive industries, and management proposals are built around the central theme that investments and policy advice in the extractive industries should lead to poverty reduction. To help governments create appropriate policy and regulatory frameworks, this paper focuses on the linkages between overarching policies and laws and the management / governance of extractive industries at the local communities. It encourages the use of new instruments designed to help ensure that local communities benefit from extractive industries.

Jan 1, 2005

Even though the economy of the United States remains in recession ? or not, depending on which economist you listen to ? muicipalities still need improved transportation, water and wastewater transit systems. And they are willing to spend the necessary funds on those systems, provided they are affordable, environ-mentally friendly and sustainable. From June 20-23, professionals in the tunneling and underground construction industry from around the world gathered in Portland, OR to learn new ways of providing those systems using the latest technology available. The North American Tunneling (NAT) conference attracted 803 attendees and 108 exhibiting suppliers of equipment and services.

Jan 1, 2010

By D. R. Wilburn

The worldwide budget for nonferrous, nonfuel mineral exploration was expected to increase by 58 percent in 2004 from the 2003 budget, according to Metals Economics Group (MEG) of Halifax, Nova Scotia. The increase comes two years after a five-year period of declining spending for mineral exploration (1998 to2002). Figures suggest a subsequent 27 percent increase in budgeted expenditures from 2002 to 2003. For the second consecutive year, all regional exploration budget estimates were anticipated to increase. The worldwide budget for gold exploration achieved about 50 percent of the total amount budgeted in 2004.This was 68 percent, or US$715 million, higher than the reported 2003 budget. The 2004 worldwide exploration budget estimates for copper increased by 70 percent, orUS$237 million, to US$577 million from the 2003 budget. The budget for nickel exploration increased 52 percent, or US$89 million more than in 2003. The 2004 exploration budget for other mineral targets (primarily cobalt, heavy minerals, industrial minerals and silver) increased114 percent, or US$118 million.

Jan 1, 2005

By G. Duncan, K. Winther, R. Ericsson

Distinct trends in grinding mill technology have emerged in recent years. In an effort to optimize overall mill performance for the needs of the End User, broad measures of logistical speed, process flexibility, operational risk, and overall costs now exert greater influence on the specification of grinding equipment. As a result, innovative alternatives to conventional grinding mill structures, supports, drives, feed, and discharge configurations are now being offered and selected with greater frequency. This paper investigates these trends in grinding mill technology, utilizing optimization and decision-theory techniques. In particular, the paper considers how specific advances in process design, product engineering, manufacturing techniques, and mining operations continue to relax technological constraints, enabling further mill innovation. In this context, a methodology is presented, illustrating how proper selection and specification of grinding mill components and configuration can target an optimization of the four End-User performance measures listed above.

Jan 1, 1999

By Derek. C. Arnold

In order to meet increasing demands for water supply in the next millennium, the Government of the Hong Kong Special Administrative Region have identified the need for a major new water treatment and transfer scheme. The project now under construction will comprise a 1.2 km long raw water aqueduct, a major new 0.25million cubic metres per day water treatment works (with space for upgrading to 1.2Mm³/d), a 12.1 km long treated water aqueduct and a primary service reservoir. In order to meet increasing demands for water supply in the next millennium, the Government of the Hong Kong Special Administrative Region have identified the need for a major new water treatment and transfer scheme. The project now under construction will comprise a 1.2 km long raw water aqueduct, a major new 0.25million cubic metres per day water treatment works (with space for upgrading to 1.2Mm³/d), a 12.1 km long treated water aqueduct and a primary service reservoir.

Jan 1, 1999

By Rudolf E. Greuer

It is undisputed that an interaction between mine fires and mine ventilation systems exists. The ventilation carries the poisonous and sometimes explosive combustion products, which constitute the greatest danger of mine fires, through the mine and it provides the oxygen on which the intensity of the fire depends. The fire, on the other hand, can produce considerable ventilation disturbances which make it difficult to predict the path along which the combustion products travel. The opinions, how serious a threat such fire generated ventilation disturbances are, vary. Where shallow deposits are mined and brisk ventilation currents are used, it is frequently felt that these disturbances are of no serious concern. Where mine workings extend over larger elevation differences and where such disturbances have been encountered and been the cause of some larger disasters, their assessment is an integral part of all fire emergency plans. The author felt that the potential of digital computers for the design of ventilation emergency plans, contrary to their acceptance for conventional ventilation planning for more than two decades, is not yet fully utilized. He designed a program for the simulation of ventilation systems under emergency conditions in particular fires. This was part of work completed for a contract with the U.S. Bureau of Mines ( Open File Report OFR 115(1)-78)

Jan 1, 1980

By William R. Yernberg

The Fifth International Conference on acid rock drainage (ICARD 2000) was held May 21-24, 2000, in Denver, CO. The three-day conference consisted of about 150 oral presentations and poster sessions that described the state-of-the-art of acid-rock-drainage (ARD) science and technology. The conference also featured a trade show. It included representatives from consulting companies and government agencies with interests in ARD, as well as other environmental issues related to mining. The conference also included field trips to ARD treatment sites and short courses on acid rock drainage issues. ICARD 2000 was planned and promoted by the ICARD 2000 Organizing Committee and the Society for Mining, Metallurgy, and Exploration, Inc. (SME). Financial support was provided by Barrick Gold, BHP Copper, Homestake Mining, Noranda, Phelps Dodge, PlacerDome, the US Bureau of Land Management, the USEnvironmental Protection Agency and the US Geological Survey. Since the original ICARD was held in Roros, Norway, in 1988, knowledge has improved of the behavior of mine wastes as have methods of environmental mitigation. The ICARD 2000 presented the latest advancements in the field of acid drainage.

Jan 1, 2000

Continued market pressure on the US coal industry was the overriding factor affecting developments in underground mining in 1986. An oversupply of coal in the spot market kept prices low throughout the year and caused a number of operations to close their doors. Operators stepped up their efforts to improve productivity at existing operations. They made technology advances and improved their relations with employees. A continuing market-related development during 1986 was the divesting of coal properties and operations by major oil companies, which were faced with economic pressures in both the oil and coal industries. Further increases in contract mining production resulted as some larger operators were unable to compete in a tough economic environment. Longwall mining is still seen by many as the technology that will provide the necessary productivity to remain cost-effective. But the number of active faces in the US declined in 1986, as reserves were depleted and economics forced some closures. At the first Longwall USA meeting in June, much attention was placed on improved technology, as electro-hydraulic controls for roof supports gained acceptance. Other recent developments include shearer initiation of roof supports, automatic horizon control for shearer drums, and collection and storage of machine data for predicting maintenance requirements. The government and academic communities continued their research on dust control at longwall faces. Jankowski, Kissel, and Daniel, (October 1986, Mining Engineering), gave an overview of progress in longwall dust control. And Mukherjee, Singh and Jayarman (November 1986, Mining Engineering), recommended design guidelines for improving water spray systems for dust control. Surface subsidence Increasing attention is being given to surface subsidence. This is primarily because of longwall mining and the Surface Mining Control and Reclamation Act. Improved methods of prediction of surface subsidence, especially computerized methods, are being continually developed. Mining engineering faculty at major universities such as Virginia are helping develop public policy and regulations concerning subsidence. As part of this effort, Unrug and Johnson identified major subsidence areas of Western Kentucky. Peng and Chen (February 1986, Mining Engineering), gave an overview of history and research of surface subsidence. And Elifrits and Aughenbaugh, (February 1986, Mining Engineering), discussed effects of moisture variations and overburden on subsidence. This research culminated in a Symposium on Surface Subsi¬dence at the SME 1986 Fall Meeting in St. Louis and the 2nd Workshop on Surface Subsidence at West Virginia University. Ground control in coal mining continued to be an item of major research interest. Some 30 papers were presented at the 5th International Conference on Ground Control in Mining at West Virginia University. And six sessions were related to coal mining at the 27th US Symposium on Rock Mechanics at the University of Alabama. At the 4th Annual Workshop, Generic Mineral Technology Center, Mine Systems Design and Ground Control emphasized efforts of the participating universities to improve ground control. Peng and Chiang summarized results of studying support capacity and roof behavior with longwall shield supports. And Unrug, Johnson, and Nandy analyzed the process of deterioration of shale roof in a case study of a room-and-pillar coal mine. The importance of geologic conditions in determining mining productivity is receiving increased attention in coal mine design in the US. Mullenex related, through case studies, the benefits to be derived through analyzing the depositional system of coalbeds as an integral part of mine design. Improved technology in this area was related by Lloyd, Semborski, and Stolarczyk. They discussed a case study of using radio imaging to indicate coal-seam discontinuities in advance of mining. Improved coal mining technology in general is being researched more heavily, to help improve US coal competitiveness. However, much of this research and development process has yet to be widely implemented. Equipment manufacturers are devoting more resources to development of continuous-haulage systems, mobile roof-supports, mine-monitoring systems, and predictive-maintenance systems using computers to extract machine data.

Jan 5, 1987