Search Documents

By Reul A. Dejú

The mineral olivine has been the subject of continued research by various authors. Paik (1967) conducted infrared and flotation studies of the adsorption of sodium alkyl benzene sulfonates on olivine. These studies are of interest from two points of view. First, in the metallurgical field it is of interest to understand the mechanism of silicate flotation using sulfonate collectors and second to a hydrologist studying the pollution of surface or subsurface waters it is of interest to study the reactions taking place when water plus sulfonates encounter a porous (silicate) medium. On the basis of Paik's study he was able to postulate a possible mechanism for the attachment of RSO3 (sulfonate radical) to the olivine surface. Parks (1969) has been studying the important influence of the structure of a silicate such as olivine on its dissolution mechanism and its related surface charge. Also Luce, a student of Parks (1964, 1965) has been studying the kinetics of dissolution of olivine using the techniques of direct solution analysis and infrared analysis. Certainly a classic in the study of silicate dissolution is the work of Murata (1940) on the reaction of orthosilicates (olivine in particular) with strong acid solutions. Many authors (Dejú and Bhappu, 1966. 1967. 1968, Dejú, 1969; Rhoades and Krueger. 1968, and Faust and blunter, 1967) have reported studies of the behavior of silicates immersed in water (especially orthosilicates) and have found that there is an exchange of cations from the silicate surface for H+ from the water. Studies by Dejú and Bhappu have also included the system olivine-water-amine.

Jan 1, 1971

By R. A. Wyman

"The froth flotation process was patented by E.L. Sulman, H.F.K. Pickard, and John Ballot in 1906 . . . . . . . . . .James M. Hyde installed the first froth flotation process in the U.S., about August 1, 1911, at the Basin Reduction Co. plant, Basin, Montana . . . . . . . . . .By 1914, 42 mining companies were operating or experimenting with the flotation process . . . . . . . . . .The period 1930 to 1960 saw the application of flotation spread to nonsulphide ores and become the key factor in the economic production of many industrial minerals". So states FROTH FLOTATION, 50th Anniversary Volume, published by AIME in 1962. It is interesting, to observe that the Mines Branch, now part of the Canadian Department of Energy, Mines and Resources, was established in 1907 through an act of Parliament entitled, "The Nines and Geology Act". In 1911, a mineral dressing group was formed and a laboratory was constructed. By 1921, an engineer was devoting full time to industrial mineral processing problems.

Jan 1, 1971

By R. J. Miller

Rock strata, natural and mining-induced stresses, and structural features can combine to create dangerous instabilities in or around longwall panels. Rock noises and properties variations associated with local stress systems can be used to characterize developing instabilities. Through a learning process at a particular mine, guidelines can be developed to allow the determination of relative risk and timing of a potentially disastrous instability. Once a dangerous instability has been identified, operational modifications can be employed to get through the instability, or active measures such as destressing can be used to mitigate the instability. This paper will discuss how an integrated monitoring system and associated data processing can be used to develop a hazard prediction capability for a longwall mine.

Jan 1, 1996

By Jim McKinley

With a growing number of mines reaching closure and seeing closure costs materialize, regulators, lenders, and banks are observing projects that fail economically by miscalculating these costs. Mine closure costs are often categorized as a type of liability which is defined as the money owed by the company to offset effects from the project, and the money available to pay for those debts (e.g., bond). Often, decisions made before Day 1 of mining (e.g., co-disposal, dry stack tailings, waste segregation) can significantly change the bond calculation. Once the bond is calculated and funded, operators are encouraged to conduct closure research and use applied science for progressive bond release prior to final closure. However, this author has observed few instances of financially significant progressive bond release, as there are typically no robust procedures for bond return, either before or during closure activities. As a result, many companies decide that entering a state of Care & Maintenance (C&M) is less risky than attempting to fund closure activities with an unknown bond return mechanism. Although perhaps less risky in the short-term, the primary long-term risk with entering C&M is that it increases the chances of the bond not covering the cost of closure and the chances of the government/regulatory agency inheriting the mine closure. Bonds are typically reevaluated on a regular cycle (e.g., five years) so every mining company goes through this financing challenge eventually.

Feb 22, 2026

By G. Vallebuona

Currently, empirical models are used for predicting the hydrocyclone performance in terms of capacity, cut size (d50,c), water split and partition curve. These models, for example those of Lynch and Plitt, have been developed and checked for hydro cyclones with diameters larger than four inches. For smaller diameter hydrocyclones little empirical modelling has been done. This paper reports extended experimental research on small hydrocyclones. For these cyclones, the suitability of existing empirical models has been checked and their accuracy compared. Modifications of the existing models equations are proposed, improving their predictive capability for the small cyclones performance.

Jan 1, 1994

By Jon C. Yingling

Lean manufacturing, pioneered by Toyota, has been credited with the most significant improvements in production efficiency and product quality since the transformation from craft manufacturing to mass production in the early 20th century. It represents a comprehensive philosophy for structuring, operation, control, and management of production systems that is believed to have wide applicability. This paper outlines major lean manufacturing principles and discusses their potential for application in the mining industry.

Jan 1, 1999

By J. A. Barrera-Godinez

Traditional batch flotation tests produce a limited number of data points from which to evaluate the kinetics of the process. In this research, continuous weighing of froth, from a modified circular flotation cell, using a computer/data acquisition system., has been coupled with chemical analyses from intermittent froth sampling. This combination has permitted the experimental data to be smoothed such that the flotation kinetic parameters could be determined with enhanced confidence. To demonstrate the procedure, a galena ore was floated to permit flotation kinetics to be investigated as a function of cell parameters. It was shown that the kinetic data of this lead flotation most closely correlated with the Huber-Panu three parameter model. In addition the results illustrated the effect of froth thickness, froth scraper rate and air flow rate on the cell performance, in terms of mass flow, grade and recovery.

Jan 1, 1990

By J. Baz-Dresch

A custom-designed shotcrete system, consisting of an 8-m3 (10-cu-yd) transit mixer and a shotcrete spray boon carrier, is used by a two-man crew to transport and place up to 25 m3 (32 cu-yd) of steel fiber reinforced, dry, silica fume shotcrete per 11-hour shift. Shotcrete is custom blended by a local supplier and delivered predampened. Mix design and quality control are performed with a computer program that develops and graphs a properly balanced mix based upon the materials sieve analyses.

Jan 1, 1992

By Sun Guangzhong, Liang Jinhuo

Adverse geological condition is a major factor which makes construction difficulty in tunneling. But if it is predicted and tunnel support is made efficiently in time, the above difficulty can be reduced. It is necessary to develop one or several effective and economical geological methods for prediction of tunnel geology while expensive and time-consuming instruments are used. This paper reviews and proposes several geological methods for prediction of fault, seam, contact zone, and groundwater inrush. These methods have been proved to be effective and economical in tunneling practice in China.

Jan 1, 1987

By J. F. Burr, D. Snyder, W. Calder

This paper provides a determination of the equivalent level of protection of the international standards relative to similar criteria used by the U.S. Mine Safety and Health Administration (MSHA) to approve two-fault intrinsically safe (IS) stand-alone equipment. U.S. mining law requires such a determination for MSHA to use alternatives to existing standards. The primary issue is to demonstrate that the international standards for equipment evaluation will provide at least the same level of protection for miners as the document currently used by MSHA.

Jan 1, 2018

By J. F. Burr, D. Snyder, W. Calder

This paper provides a determination of the equivalent level of protection of the international standards relative to similar criteria used by the U.S. Mine Safety and Health Administration (MSHA) to approve two-fault intrinsically safe (IS) stand-alone equipment. U.S. mining law requires such a determination for MSHA to use alternatives to existing standards. The primary issue is to demonstrate that the international standards for equipment evaluation will provide at least the same level of protection for miners as the document currently used by MSHA.

Jan 1, 2017

By W. R. Sharp

The ability to target, delineate, excavate, and produce local resources is essential to the establishment of man's long-term presence in space. Many procedures and equipment utilized to mine resources here on Earth may be directly applicable on the lunar surface, while others may need extensive redefinition and development. This paper compares, for a lunar base, the alternative of burrowing into and below the lunar surface with that of surface mining. A conceptual underground mechanical excavator is presented.

Jan 1, 1991

By R. R. Oder, R. E. Jamison, E. D. Brandner

This paper presents the preliminary test results obtained using a 0.38-kg/s (3,000-lb/hr) beta prototype MagMill. In processing Upper Freeport coal, the beta prototype recovered 82 % of the weight of the feed and 91 % of the heat content while reducing the potential emissions of sulfur by 61%. Pyritic sulfur in the MagMill product was reduced by 78% compared with that in the feed. For all runs, the mill product particle size was controlled to between 70% and 80% -741m (200 mesh). Recoveries of mercury, arsenic and selenium ranged from 35% to 45% of the amounts found in the feed. Power draw was reduced by 26%, and mill throughput was increased by 9% compared to the pulverizer operating with no magnetic separator attached.

Jan 1, 2002

By John Jonkman

The cost of equipment maintenance is the largest single expense at many mines and processing plants. It is not unusual for a maintenance and repair budget to be larger than 50% of the punt's total budget. Generally, in the mining industry, 400-60% of the work force in a plant reports to the maintenance department. Studies have shown that many plant maintenance workers are only 33 to 40% productive, working 2.6 to 3.7 hours of every 8-hour day. In recent years, many companies have begun to recognize that- productivity improvements and cost reductions can he achieved by upgrading maintenance methods. This paper discusses ten common causes of low maintenance productivity and how recent advancements in computing technology can be utilized to address these causes for low productivity.

Jan 1, 1986

By J. A. Cooper, M. R. Petersen, P. O. Jackson, J. C. Langford

The organic, inorganic, and radiological characteristics of airborne aerosols have been measured as a function of particle size in controlled atmosphere test chambers and operating uranium mines. Concentrations of benzo(a)pyrene in two mines ranged from 26 to 57 ng/m3 of air. The carbon chain length of adsorbed n-alkanes was correlated with particle size. Normal mining activities produced an ore dust aerosol with mass median aerodynamic diameter (MMAD) greater than 2 µm. The elements Na, Al, Si, K, Ca, Ti, V, Fe, and U exhibited elemental ratios similar to bulk ore and had comparable MMAD's. The S, Zn, and Pb were higher in aerosols than bulk ore and were associated with smaller MMAD particulates. Radon daughter particle size distributions were influenced by the kinds of particulates

Jan 1, 1981

By C. Dirscherl

"Declining ore grade, leading to increased material transport and plant throughput requirements, is one of the major challenges in the current mining environment. This is accompanied by rising energy and labor costs, decreasing plant productivity and the requirement for highest plant availability. Siemens’ answer is the latest gearless drive technology for grinding and conveying. Gearless drive solutions are surpassing the mechanical limits of conventional drive systems serving to utilize the principle of economies of scale. By elimination of various components of the drive train, the maintenance activities and spare parts inventories are reduced. The advantages are culminating in the incomparable availability of the Siemens’ gearless drive technology of 99.46 to 99.71 percent — as confirmed by real operational data from the Antapaccay Mine in Peru. It was the first plant worldwide to use gearless drives for both applications.The gearless principleThe principal idea behind a gearless drive system is to reduce the number of components and diversity of parts, especially those components that are at the edge of current manufacturing or power limits are eliminated. The used equipment provides the possibility to scale up and increase the power transmitted to the driven machine. This finally results in a possible increase of throughput respectively transported or processed material.In order to apply this principle of simplification, the components of a conventional drive system are examined. They consist of:• Driven equipment (mill, conveyor, slurry pump).• Components altering the rated speed (gearboxes, girth gear/pinion).• The electric motor.• Starting devices for the motor (VSD, CCV, LRS, clutch), which are necessary because a direct across-the-line start of high power motors with load would result in a significant drop in the line supply voltage.• Alternatively a variable speed drive (VSD) or cycloconverter (CCV) to utilize the possibility of speed variation during operation.• The electrical supply system (cables, switchgear, transformers, protection equipment)."

Jan 1, 2015

By Basak Anameric

This study reports preliminary feasibility investigations for utilization of the selective carbothermic reduction and smelting (SCRS) processing scheme to beneficiate low-grade iron-manganese (Fe-Mn) mineral deposits from MN, USA. The study includes laboratory-scale demonstrations using an induction furnace and production of various products by manipulation of operational parameters. The products include alternative iron (Alt Fe), high carbon ferromanganese (HC FeMn), alternative silicomanganese (Alt SiMn), and upgraded manganese concentrate (Mn conc). All of these products have commercial value and can be used in various applications as raw materials.

Nov 23, 2020

By C. Sun

With complex component, higher salt content, low biodegradability, DSD acid oxidation wastewater could not be efficiently dealt with traditional methods. It is pointed that the coal water slurry could be made with DSD acid oxidation wastewater of different concentration and the density of coal water slurry could be up to 70%, while its viscosity is only 850~930 mPa?s. The coal water slurry could be perfectly jetted and burnt under different conditions. The higher density the DSD acid oxidation wastewater has, the better properties the coal water slurry have. The pollution components and characteristic group of DSD acid oxidation wastewater are similar to the additives of coal water slurry, so it could be used as a kind of usable additive of water coal slurry. It is so reasonable and feasible to make coal water slurry with DSD acid oxidation wastewater that the pollution of DSD acid oxidation wastewater can be solved completely.

Feb 23, 2014

By G. A. Kordosky

Solution mining followed by solvent extraction-electrowinning (SX-EW) is one possible way to economically extract copper from ore bodies which cannot otherwise be profitably exploited. Published costs for the unit processes of SX and EW are out of date especially in view of the newer reagents now available and the newer circuit configurations, This paper updates the costs for SX-EW in 1985 dollars and also discusses some of the trade-offs which must be made when designing an SX-W plant.

Jan 1, 1986

By Harry M. Conger

Thirty years ago, the U.S. gold mining industry was hanging on by its fingernails. Save for one great mine, the Homestake, most production was coming from copper smelters such as Kennecott and Magma. Even Homestake itself was under great pressure from rising costs and a fixed price for gold. The outlook was dim, to say the least. Today, as it has for most of the past decade, the American gold mining industry stands among the world leaders in production, and in the development of mining and mineral processing technology. What caused this dramatic change? Obviously, the freeing of the gold price was a major factor, as was the decline in South African production, but these events alone could not have created the U.S. strength we see today. It was technology, investment, and the determination of miners to build an entirely new industry that were the indispensable ingredients. The U.S. Bureau of Mines, with great foresight, had begun the research that led to heap leaching before the gold price began to rise, and Newmont had committed to build a small mill at Carlin, a move then considered quite risky. From that point, the U.S. gold mining industry was placed on lower-grade ores then being found in Nevada and elsewhere, but it was soon apparent that we would have to develop new technologies to deal with more refractory ores, carbonaceous as well as sulfide-bearing. This is now being done with considerable success. Despite its success, or perhaps because of it, the gold mining industry has come under pressure from various groups who characterize their activities as motivated by "public interest." The public interest they refer to properly include the health and safety workers and impacted communities, as well as protection of the environment, and with these concerns we miners have relatively little argument. In fact, we consider health, safety and the environment among our highest priorities, and not just because regulations may require us to do so. The argument, however, is not about the regulation of a viable mining industry, it is about a well-organized movement to attack and condemn mining in the media and to misrepresent its importance to the Nation and its willingness to accept responsible regulation. Once largely local or regional, the interest groups to which I refer are now quite large, national in scope, and even becoming international. This trend, taken together with finances raised from their dues and contributions, would make the interest groups formidable adversaries for mining, but their grip on the media enormously magnifies their influence. Unfortunately, it also makes possible the wide dissemination of incomplete, incorrect or slanted information. I am not here to "bash" the interest groups. On the whole, I believe that many of them have made positive contributions to society. As conservationists, however, I question their authority to make, or foster, decisions about which American industries and communities live and which die. To illustrate, I would like to present for your consideration the problem of cyanide, one of the issues over which the gold mining industry is most threatened. CYANIDE-POISON OR MIRACLE SOLVENT? Let me get this out of the way right up front: cyanide in most of its chemical forms is toxic. In some forms it is also listed as a carcinogen. These are adverse characteristics cyanide shares with a considerable number of industrial chemicals, including some that are widely used without the stringent regulations already in place for the mining uses of cyanide. In these uses, by the way, the risk to humans comes from direct ingestion of cyanide or cyanide-bearing solutions, or from the accidental acidification of solutions leading to release of hydrocyanic acid gas. That these risks are under control in mining can be seen from the fact that, in modern U.S. practice, there has never been a documented fatality attributed to cyanide! Because of its toxicity, cyanide cannot enter and be accumulated in the food chain. It can, however, be a threat to birds and animals that ingest cyanide-bearing solutions. Protection against this is, quite properly, a responsibility of individual mining operations, and considerable sums are spent each year to prevent or reduce bird and animal exposures. It should be evident, though, that many human activities, including highway traffic, windmills, use of pesticides and the like, result in bird and animal losses. Mining's use of cyanide, and the measures taken to protect birds and animals, should be considered in context. Cyanide must be kept out of surface streams and groundwater, and existing regulations mandate this. Any cyanide residues left in leach heaps, waste dumps and disused facilities must be eliminated, and we have proven technologies to do this now, just as we have means to detoxify tailings prior to disposal. The gold mining industry decries those rare instances when irresponsible operators fail to deal with contamination, and agrees that they should be held responsible. We do not agree, however, that the great majority of responsible companies should be punished, in advance, for accidents that have never happened. So much for the poison, what about the "miracle solvent?" Is that an overstatement? Well, consider the fact that gold has been called "noble" from earliest times, because it does not oxidize under atmospheric exposure, and that it appeared to the ancients to be utterly insoluble. Later generations of scientists did discover that it could be dissolved, but only by a combination of acids so potent that it became known as aqua Regia. Later still, it was found that chlorine would also dissolve gold, and attempts were made to base commercial processes on this, without a great deal of success. It remained

Jan 1, 1995