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By Donald L. Gaughenbaugh

Under the terms of the 1970 amendments to the Clean Air Act, the EPA established national ambient air quality standards for a number of pollutants. Sulfur dioxide (SO2) was one of these pollutants. These ambient air quality standards have had perhaps their biggest impact on the power utilities. In an effort to meet the air quality standards set forth by the EPA, utilities using high sulfur fuels have been forced to install flue gas desulfurization (FGD) systems. The majority of FGD systems in operation today are nonregenerable systems, that is the by-product of the system is disposed of, usually into settling ponds. Limestone slurry is the most common reagent used to remove SO from the flue gases. The calcium carbonate (limestone) slurry interacts with the flue gas, absorbing the SO2 and forming a by-product of calcium sulfate/sulfite which is disposed of.

Jan 1, 1986

By Terry S. Maio

In 1978, Ozark Lead Company made the decision to expand the capacity of its mine/mill complex by 33%. The objectives of the expansion were to (a) increase mine' production capacity by 1816 tonne/d(2000 TPD), (b) increase lead metal pro¬duction by 21,790 tonne/y (24,000 TPY) and to (c) construct new facilities and/or modify exis¬ting equipment to accomodate the increased pro¬duction. The intent of this paper is to give a brief explanation of the equipment installed and the overall production and metallurgical benefits-realized from this expansion. The expansion was completed in the second half of 1980 with all equipment debugging and fine tuning completed by the first' quarter of 1981. The concentrator modifications and improvements were basically restricted to four areas: (1) materials handling, (2) automation: of the mill grinding circuit, (3) the increase of flotation capacity, and (4) concentrate dewatering.

Jan 1, 1983

By Katherine Hynard, Colin Eustace

Suboptimal decisions introduced during the mine planning process are generally a consequence of both a myopic view of planning objectives as well as time and resources available to convert longer-term plans into execution plans. Erosion of strategic mine plan value in conversion to execution plans is likely to amount to billions of dollars each year. When integrated with operations data feeds, simulation and optimization tools can be used to preserve the value in the strategic mine plan. Optimization models are capable of both automating production of execution plans and improving performance. This reduces the manual burden of revising plans while improving alignment with long-term production objectives. Simulation models can also support the process of developing effective execution plans by providing forward visibility of mine operations performance. They can also be used to test the robustness of optimized execution plans and response to operational variability and disturbances.

May 1, 2025

Several years ago, North American mining companies began to realize they needed to expand their spheres to remain viable. This strategy has been successful, according to Robert W. Schafer. Today, companies from other continents have also recognized the need for an international view for long-term growth and viability, he said. Schafer is vice president for exploration with Kinross Gold. He was the program chairman and moderator of the keynote session at the 1997 SME annual meeting, held in Denver, CO, Feb. 23-27. The theme of the meeting was "Minerals - Serving the Global Community." A record attendance of more than 6,000 people participated in the meeting, which featured 415 exhibitors occupying 582 booths. The title of the keynote session was "Corporate Perspectives on a Global Minerals Industry." Each of the three keynote speakers discussed a different perspective of a global minerals industry.

Jan 1, 1997

By M. Pope

By 1950, packaged oil and gas fired boilers were on the market for capacities up to 30,000 lbs./hr. By 1962, capacities were up to 100,000 lbs./hr. and even higher when separate heat traps (economizers and air preheaters) were attached to the boiler packages. During this period, complete packaged coal fired boilers were developed into the 10-15,000 lbs./hr. range. Oil and gas fired plant designs became very compact, "basementless", and far: less costly than the coal fired plants of any capacity. Coal fired plants remained large and expensive, required field erection of boilers and required basements. With the spectacular strides made in automation, oil and gas plants became far less costly to operate, requiring only the part-time attendance of a single operator. Some advances were made in coal fired plants, but not to the degree attained by the fluid fuel competition.

Jan 1, 1965

By James E. Lawver

During 1981 the Florida phosphate industry produced more than 43 million metric tons of phosphate rock - about one-third of the entire world production and also generated nearly an equal amount of waste clay and waste clay-sized product that requires dewatering and disposal. The material balance of solids and water for a typical Florida phosphate mining operation is shown in Figure 1. Historically, the industry has impounded clay waste (about 60% below ground and 40% above ground) in earthen dams, often as large as 800 acres and occasionally greater than 60 ft. high. The dams have served the triple purpose of: 1. Dewatering initial 3% solid waste clay for process water re-use. 2. A reservoir system to minimize water discharge from the mining area and to capture and store rainwater thus minimizing deep well pumping requirements. 3. The ultimate densification and storage of waste clay.

Jan 1, 1983

By Vikram P. Mehrotra

A laboratory investigation was carried out to study the influence of asphalt, bentonite and corn starch binders on the pelletization kinetics of coal fines and on the quality of the resulting pellets. Pellet quality was evaluated in terns of the compression strength, impact resistance (drop test), abrasion resistance and resistance to severe weather conditions. The amount of binder addition did not significantly influence the pellet growth kinetics. However, the pellet quality varied markedly depending upon the type and the amount of binder used. Experimental results are explained on the basis of the mechanism of interaction between the coal particles and the binders. Of the three binders tested, corn starch proved to be the best in all respects but for the resistance to water penetration. Finally, a combination of corn starch (imparting strength) and asphalt emulsion (imparting resistance to water penetration) was found to yield the best quality coal pellets.

Jan 1, 1981

By J. B. Rasmussen

As part of a purchase of a fleet of Caterpillar 785 trucks, Round Mountain Gold Corp., Cashman Equipment Co. and Caterpillar Inc. entered into a four-year contract for the major maintenance of the fleet of trucks. This contract includes fixed costs and guaranteed availability. The results have been excellent, and the fleet of trucks performs well. History The Smoky Valley Common Operation is a unique mine. Through a mixture of diligence and foresight, it has become the largest open-pit, heap leaching gold mine in the world. This was no small feat considering the remote area surrounding the mine. Round Mountain is located in north-central Nye County, NV. To the east of the town and mine lies the Central Toquima mountain range. To the west is the Toiyabe mountain range. Between them is the Big Smoky Valley, a flat expanse of sagebrush, salt grass and fine dirt.

Jan 1, 1991

By V. Kecojevic

Environmental and economic costs related to equipment fuel consumption and carbon dioxide (CO2) emission present a substantial challenge to the mining industry. Haul trucks are an integral part of the overall surface mining system and they consume a substantial quantity of fuel. Consequently, they produce a significant amount of CO2. The objective of this research is to (i) establish a mathematical relationship among a truck?s fuel consumption, power and engine load factors and (ii) determine the amount of a truck?s CO2 emission and the associated cost that may arise from potential CO2 legislation. In order to achieve these objectives we have considered original equipment manufacturer (OEM) haul trucks, commonly used in surface mining operations. The research presented here may be used by mining professionals to help determine the cost and environmental burden of the trucks? application, and efficiently manage energy consumption.

Jan 1, 2011

In 2002 the authors updated the MFire model developed by the US Bureau of Mines. MineFire, developed by Mine Ventilation Services, Inc. (MVS), uses the MFire model to perform mine fire simulations on typical mine ventilation networks. The MineFire program is capable of producing visual schematics and other analysis tools for input and output of the MFire model. The MFire model, however, was limited to 500 branches and 10 fans. This paper discusses the newly modified MFire model that is now capable of modeling over 5000 branches and over 400 fans among other expansions and improvements. Given the long history and proven track record of MFire, the expansion did not modify the core calculation methods or results. This paper focuses on a general discussion of the MFire program and issues encountered in expansion of the algorithm. An example large network with simulation results is discussed.

Jan 1, 2011

By d&apos, J. A. Oliveira, A. K. L. Resende, L. F. G. Assumpção, J. D. Neto

Kaolin samples from Rio Capim Resources were treated in conventional and superconducting magnetic separators to study the main variables that influence the impurity removal process. Two coating clays and a delaminated clay were tested. The variables studied were retention time (cross-sectional velocity), magnetic-field intensity and matrix type. The feed brightness ranged, from 84.7% to 87.6% ISO, for the coating clays and ranged from 80.7% to 85.4% ISO for the delaminated clay. Using a conventional magnetic separator with an applied, field of 1.5 to 2.0 T (tesla), the brightness values were higher than 88% ISO for the unleached coating claw products and were higher than 87% ISO for the unleached delaminated product. With a maximum field intensity in the superconducting machine of 5.0T unleached brightness values higher than 88.5 % ISO were attained for both coating and delaminated clays.

Jan 1, 1997

By Richardo Montoya

Radomiro Tomic, the new CODELCO division, is a copper deposit located at 3000 m a.s.l. and 40 Km from Calama in northern Chile. It has total oxide reserves of 802,000,000 tonnes with an average grade of 0.59% total Cu (using a cut-off grade of 0.4% total Cu). The copper oxide ore is mainly atacamite and chrysocolla. Startup is expected to commence in December 1997 of 150,000 t/y of Cu cathodes. Future expansion to 250,000 t/a of Cu cathodes is currently being planned. The process consists of an open-pit mine, a two-stage crushing system, agglomeration with sulphuric acid and emplacement on a heap leach pad for a 45-day leaching cycle. Solvent extraction and electrowinning will produce LME "A grade cathode. A number of significant technology innovations have been incorporated into the project.

Jan 1, 1998

Ceremonies for the induction of five mining industry pioneers into the National Mining Hall of Fame are scheduled for Saturday, Sept. 25, 2004 at the Las Vegas Hilton in Las Vegas, NV. The 17th Annual Mining Hall of Fame Induction banquet will begin with a reception at 6 p.m., followed by the dinner and program at 7 p.m. The five inductees are Georgius Agricola, David William Brunton, Herbert E. Goodman, David Ray Mitchell and Robert Peele. Georgius Agricola (1494-1555) wrote De ReMetallica, an original and valuable work that discussed everything known about mining during the first half of the 16th century. In De Re Metallica, Agricola reviewed practical means of finding ores, methods of surveying and mining, the assaying of ores, types and uses of mining machinery, smelting, mine administration and more. David William Brunton (1849-1927) is best know

Jan 1, 2004

By Peter T. Luckie

Up until the past couple of years, thermal coal dryers were only used to dry midwest and eastern United States bituminous coals. These dryers were primarily installed at coal preparation plants to freeze proof the coal and lower the transportation costs per BTU. Today thermal coal dryers are being specified to dry western sub-bituminous and lignite coals for these and other reasons brought about by the intense interest in coal gasification and liquefaction. One reason for drying western coals ahead of a coal gasification plant is the elimination of surface moisture which would prevent efficient sizing of the coal, since feed material size consist is very important in most commercial coal gasification processes. Thermal dryers are being proposed for liquefaction processes because of the need for a feed material containing approximately 4% or less total moisture Future coal gasification processes may also need to reduce feed material moisture content.

Jan 1, 1975

By MSHA

Not quite a year ago, during a speech to a group of mining professionals in Washington, DC, the subject centered around the long-range importance of conducting research projects and how much that research needs to specifically apply to health and safety matters in our industry. The point was made about the critical need to work together with government, private industry, labor organizations and academia speaking with a unified voice as we all march into the future together. The fundamental benefits of competitive research were mentioned -- to improve our quality of life, to develop our energy resources, to achieve a safe and healthy environment and to ensure long-term economic growth. Very importantly, emphasis was given to the natural link that makes my agency, the Mine Safety and Health Administration, and the National Institute for Occupational Safety and Health -- NIOSH -- the beneficiaries of each other's findings.

Jan 1, 1999

By Deepak Malhotra, Sean Armstrong, Linda Baltich

The economic profitability of any mineral company is dependent upon maximizing mineral recoveries while minimizing costs. The effectiveness of any strategy to meet this objective is dependent upon firstly obtaining quantitative information concerning the steady-state metallurgical balance of the plant, and secondly, how efficiently this information is used to improve/optimize plant performance. This two-step approach can be designated as a "plant audit." Plant audits on a routine basis can be very expensive and time-consuming. Most plants have reduced staffs to cut costs. The remaining staff has to spend time to solve production/operation problems, thereby leaving limited resources (i.e., people, time, and money), for plant auditing. This paper briefly reviews plant auditing categories, and a systematic approach to auditing which has been successfully used at several operations. An example illustrating the use of this approach in gold operations is discussed in this paper.

Jan 1, 1992

By Rod Knopp

Each year approximately 5,000 tons of a sulfide concentrate grading 1 ounce gold per ton are produced at this operation. The material is refractory and as shipping costs and custom smelter charges increase, options to process it on site are becoming more attractive. Three methods of treating the ore have been investigated in detail. The first option of ultra fine grinding the concentrate produces a 35% gold recovery with relatively low capital and operating costs. A second option of pressure oxidation is very capital intensive and has high operating costs but recoveries in the order of 95% are achievable. The final option, biological leaching offers both capital and operating costs which are less than pressure oxidation, while still achieving 90% gold recoveries. Bioleaching of gold concentrates has been gaining acceptance but there is a risk factor associated with this or any emerging technology.

Jan 1, 1990

By Matthew J. Hrebar

A comparison of hydraulic shovels (HS) versus front-end loaders (FEL) is commonly made when an excavator with some degree of mobility and medium reach is required. These applications are often found in hard rock open pit and surface coal mining applications, among others. The purpose of this paper is to present a comparative economic study of the two excavators. Production data was collected from both HS and FEL manufacturers as well as operating mines. Availability, operating costs, and estimated operating life were gathered from operating mines, while capital costs were obtained from manufacturers. The data was limited to studies and operations which included both types of mid-size excavators. The economic study is followed by a discussion of other factors considered by mine operators in excavator selection. The study was originally made for a presentation at the 23rd Intermountain Minerals Conference at Vail, CO.

Jan 1, 1992

By John Pekrul

Coeur Rochester Inc. located in north central Nevada, operates an open pit mine moving a total of 16 - 18 million short tons of material per year. A three stage crusher produces approximately 8 million tons of a minus half inch product that utilizes truck stacking to construct a heap leach with a zinc precipitation recov­ery plant. Coeur Rochester recovers approximately 6.0 - 7.0 MM ounces of silver and 60 - 80 K ounces of gold annually. Current metal prices and good operating practices require contin­ued review of operating systems that support the operation, thus the development of a Strategic Mine Plan. This Strategic Mine Plan provides managers, engineers and supervisors a means to improve their operations through three main objectives: 1. Reduce operating costs, 2 .. Increase production, 3. Increase mine life (reserves). These three main objectives will be reviewed in context to their current status and past performance.

Jan 1, 1999

By Q. Yuan, B. Yarar

Steric stabilization is a phenomenon observed when relatively high doses of flocculants are added to fine particle suspensions. Experiments were conducted to establish conditions under which medium viscosity and the sedimentation properties of black sand components in a slurry could be controlled so as to enhance the selective sedimentation of gold grains. It was shown that black sand concentrates containing as low as 2.65 g/mt gold could be upgraded by selectively hindering the sedimentation of non-gold components in an aqueous slurry. This paper presents data describing the theory and practical implementation of this cyanide or mercury-free novel approach where gold could be concentrated by as much as 15 times with relatively high recoveries. The relationships of solids content of slurries, type and dose of polymers with the recovery process are documented. Key words: Gold, black sand, selective flocculation, steric stabilization.

Jan 1, 1993