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By J. N. Van der Merwe

The paper provides an overview of subsidence research which was done by the Sasol Company in South Africa over a period of more than six years. The magnitudes of subsidence elements in South Africa are largely similar to those in the U.S.A. and Australia, as opposed to Europe. The research resulted in a subsidence prediction method with a new approach to the prediction of ground strain. The paper also describes the effects of subsidence on various commonly occurring surface structures such as roads, overland conveyor belts, pipe lines and power pylons. It is concluded that while most structures are not specifically designed to accommodate mining induced displacements, they can nontheless be undermined safely and economically with only minor precautions.

Jan 1, 1986

By Thomas E. Shufflebarger

Definition of glass sand prospects may be modified by constraints which range from demography to critically important product-control. Characteristics of usable raw materials, physical and chemical, are discussed; an ideal raw material is defined. Following field investigations and preliminary sampling, evaluation of selected prospects includes use of modern drilling techniques, viz.: core, percussion (air-hammer), auger, jet, rotary jet, split-spoon and other. Nearly complete core (sample) return is mandatory. Land-use regulations, availability of water and transportation continue to direct exploration in a major sense. But fitting a prospect to burdensome politics nay be considered a decidedly negative factor.

Jan 1, 1983

By P. Zhang

A multiyear, comprehensive study of flotation reagents used in phosphate beneficiation was conducted. The study involved the evaluation of pure fatty acid compounds, comparison of various anionic collectors and testing of iso-acids. Various C12 to C22 fatty acids were tested as Florida phosphate collectors. The saturated fatty acids were found to be very poor collectors when using the standard conditioning procedure, whereas the unsaturated C16 to C22 fatty acids showed fair to good phosphate collecting ability. The C18 fatty acids oleic, impure oleic and linoleic and the C20 eicosenoic acid were shown to be the best phosphate collectors. The best flotation results were obtained using Liqro GA tall oil and oleic acid. Four isostearic/iso oleic acid type fatty acid collectors were compared with a commercial grade oleic acid and with Liqro GA tall oil as phosphate collectors using standard laboratory conditioning and flotation procedures. The most selective collector evaluated was Century 1108, a high isostearic acid-type reagent. However, it was concluded that this excellent-performing reagent was too expensive for commercial use. Overall, the most promising reagent was probably Century MO-5. This collector is essentially an iso-oleic acid/stearic acid mixture (not isostearic acid), and it costs much less. This program laid a sound foundation for developing single collector, all anionic flotation processes.

Jan 1, 2009

By T. Negeri

Flotation is the most efficient and preferred solid-solid separation method in mineral processing. However, enhanced production of high-grade concentrates at sufficiently high recovery still poses technological challenges to-day. A novel flotation method to produce final-grade concentrates from finely-ground ores in a single step is being developed and tested by CANMET. For the complex sulphide ores tested, grades are superior while recovery is considerably improved. Furthermore, concentrate production rates, at similar recoveries, are faster than for the conventional rougher-scavenger-cleaner configuration. This paper discusses the physical operating parameters affecting Cu-Zn flotation metallurgy.

Jan 1, 1995

By Eti Purwaningsih, Widi Astuti, Erik Prasetyo

Increasing demand for high-grade manganese (Mn) ore has led to the practice of selective mining, which produced low-grade Mn ore as waste and in the long term could lead to environmental pollution. Research had been carried out to extract Mn from low-grade ore, which mostly exists as black Mn(IV) oxide (MnO2). Most extraction methods involved the reduction of insoluble MnO2 to soluble Mn2+ in acidic media. Metals other than Mn are also transferred to the pregnant leach solution (PLS) during the leaching process, especially iron (Fe). Due to high Mn concentration in PLS, precipitation is considered the best method to isolate Mn from PLS compared with solvent extraction and ion exchange/absorption. However, due to unselective leaching, the presence of Fe in the PLS makes the Mn separation and purification difficult. Therefore, in this research, the parameters affecting the selectivity of Mn over Fe in leaching process were investigated.

By R. V. Ramani

Demands on available lands will continue to increase due to the projected increase in population and industrial expansion. Though there is an upper limit on the available lands, the multi-use nature of the lands will make it possible to meet these demands. However, this will not happen without adequate planning. Land uses can be broadly categorized as non-renewable and renewable. Lands with mineable resources can be dedicated at some point in time to the extraction of resources. Such a dedication, however long-term, is only temporary because of the non-renewable nature of the mineable resources. Implied here is that the land will be available before and after mining for other uses. Planning for such lands must have the objective that, as far as practicable, no non-renewable uses are pre-empted and no renewable uses are permanently destroyed. The primary aspects of this planning process will be addressed in this paper, These aspects include a discussion of planning responsibility, data needs and availability, the integration of mine planning and post-mining land use planning and a long-term plan for resource conservation and utilization. Minerals, together with agriculture and forestry products, are the primary sources of wealth. Therefore, to avoid land development that may pre-empt future mineral resource utilization, the local planning groups must be aware of the mineralization and mining potential. Much work needs to be done to identify and characterize the mineral resources. Even more work is needed in land use planning for lands with mineral deposits.

Jan 1, 1982

By Bruce E. Nesbitt, Paul G. Lhotka

At Lupin mine gold is spatially and genetically linked to zones of hydrothermal alteration in iron-formation which are symmetrically developed adjacent to late Archean quartz veins. Immediately adjacent to the veins, coarse grained, typically gold- and sulfide-poor, calc-silicate rocks are often present. These rocks comprise hedenbergite + quartz ± grossular garnet ± epidote ± scheelite ± calcite. Sulfides (pyrrhotite, arsenopyrite and loellingite) and gold are concentrated in the next zone and occur with hornblende-rich rocks comprised of hornblende, quartz, hedenbergite and grunerite. Furthest from the veins are gold- and sulfide-poor, grunerite-rich iron formation comprising grunerite, quartz, hornblende and sometimes magnetite. Although the alteration assemblages have similarities with skarns, they develop in iron formation, and are at best indirectly related to intrusive igneous rocks. Geological and geochemical data clearly indicate the calc-silicate rocks are metasomatic in origin.

Jan 1, 1990

By E. J. McGuire, E. W. Brickle

INTRODUCTION Several recent technological improvements - largely by the convey-or industry - have increased the importance of inclined shaft construction for developing mines where ore deposits are relatively shallow. With these newer systems, long conveyor haulages are economically feasible, allowing mine owners to justify the expense of the inclined shaft or slope. What this actually means is that they can now take advantage of the versatility this construction offers. For example, haulage capacity can be changed by conveyor additions or replacements; equipment can be trammed to and from the surface quickly without costly breakdown and re-assembly; and a walkway is available for workers in the event of an emergency. Now, another innovation may accelerate this type of construction, the use of tunnel boring machines or "Mechanical Moles" to dig the slopes. While conventional. drill and blast methods have been used previously to build inclined shafts, the tunnel boring machine technique offers greater production rates, higher safety and a better, much cleaner bore. McGuire Shaft & Tunnel Corporation of Ft. Smith, Arkansas recently started such a slope project - the first ever bid by a contractor based on the use of a "Mechanical Mole".

Jan 1, 1997

By H. R. Manouchehri

"Pyrrhotite (Po) is one of the most abundant sulfide minerals in processing industry and must be rejected in most cases. Particularly, Po rejection and its selectivity against pentlandite (Pn) have long been a challenge due to similarities in the mineral composition of the two minerals and the collectorless flotation characteristics of Po. Xanthates have been widely used to promote sulfide mineral flotation; however, in the presence of xanthates, the redox potential established at the mineral/solution interface is most important, determining the flotation performance. In this paper, the importance of electrochemistry in Po and Pn flotation has been demonstrated and a comprehensive study was conducted on two different feed streams (i.e., magnetic concentrate and scavenger cleaner streams, containing magnetic and nonmagnetic forms of Po, respectively), from Vale’s Clarabelle Mill in Sudbury, Ontario, with an objective to determine if improvements in Po rejection and Pn recovery could be achieved by controlling pulp electrochemistry. By conducting a series of flotation tests under different Eh conditions and reagent usage schemes, it was revealed that higher Po content in the magnetic stream may protect Pn from being oxidized, improving Pn recovery. The results indicated that at low oxidizing pulp chemistry, the rest potential for the Pn is still high enough to allow the formation of dixanthogen to promote its flotation. Using a Pt electrode, it was found that by controlling pulp potential at -50<Eh< +50 mV, the Pn recovery and Po depression would be satisfactory. The results, using mineral electrodes (Outotec Chena analyzer), indicated that selective separation can be achieved if low-to-moderate oxidation potentials (0 to 100 mV) or reduction (0 to -100 mV) potentials are monitored using Pn and Po electrodes. Mixing two streams at 50:50 wt % would be possibly beneficial in selective separation.IntroductionPyrrhotite (Po), Fe1-xS, is one of the most abundant sulfide minerals in the processing industry. It is an iron-deficient sulfide that occurs either in monoclinic or hexagonal form. The monoclinic one is richer in sulfur and is ferromagnetic, whereas the hexagonal Po is poorer in sulfur and has no magnetic properties. In general, the ferromagnetic properties of natural Po increase with increasing sulfur content. Although Po holds significant iron content, it is not used as a feedstock for the iron and steel industry due to the difficulty in achieving complete removal of sulfur. The common availability of iron oxide ores makes the iron sulfides irrelevant for the steel industry."

Jan 1, 2015

By Jack W. Eloranta, Michael J. T. Orobona, Peter R. VanDelinder

Ore blending for process optimization is becoming an increasing factor for managing cost and productivity. Economic mining and processing a very low value ore in an extremely competitive market results in constant cost-cummng initiatives. The inherent conflict between the lowest possible mining cost and the lowest possible milling cost is reviewed here in the context of blasting for autogenous mills. Iron ore blending focuses on a number of properties-liberation values, weight recovery and concentrate silica being the most important. Other chemical and metallurgical factors are also commonly controlled. Recent research has fueled an emerging interest in blending on physical ore properties as well. Fully autogenous mills rely on the large, competent fraction of crushed feed to act as grinding media. Previous test work indicated that Hibtac mills require specific amounts of 6- to 10-inch ore. High recirculating loads require a steady influx of large rock fragments. Blast designs, therefore, are presently characterized by wide patterns and low powder factors. Current efforts are aimed at improving mill throughput while reducing overall energy costs. Based on research and published case studies and the advent of optical measuring devices, Hibbing Taconite Company has embarked on a blast optimization program to identify optimum mill feed and to design blast fragmentation goals for each geological unit and each mining area. This paper outlines the preliminary findings of an ongoing, broad-based team effort which requires close cooperation of geologists, mine engineers, crushing and milling personnel. Three specific areas of investigation are reviewed: I) Historical relationships between powder factor and mill performance, 2) Blast fragmentation modeling using the Kuz-Ram model, and 3) Drill

Jan 1, 2004

By David K. Sitler

Continuing advances in manufactured diamond materials used in rock cutting tools have created a new generation of high production tools for mining. This paper will review the three major manufactured diamond products available for the mining industry as supplied by General Electric Company, Specialty Materials Department, and examine the ways in which these materials are employed. As an integral part of this examination, the economic impact of manufactured diamond tools will be evaluated. Time and again, one will find that the premium price of these tools is economically justified when compared to traditional tools.

Jan 1, 1985

By C. Geier

Previous mine incidents show weaknesses in mine rescue preparedness from poor training in decision making, leadership and incident command center (ICC) protocols. Computer simulations offer a larger range of training opportunities for mine rescue teams focusing on exploration and communications. The mine rescue simulator developed by the Colorado School of Mines and Rite Solutions Inc. utilizes four computers for the instructor and team, with the instructor monitoring the team?s progress. As the team explores, it relays information back to the Fresh Air Base, which then reports to the ICC. This forces a three-step communication procedure, enhancing the team?s overall communication skills and developing ICC protocols. The simulator is decision-based, demanding team decisions be made quickly. Upon completion, teams commented positively. Generally, participants said that the simulator is useful for learning how to communicate and make decisions during mine rescue emergencies. This mine rescue simulator improves team training, providing effective communications practice with an easy setup and no production interruption.

Feb 1, 2014

By R. R. Swanson

Liquid ion exchange is becoming more and more important in hydro-metallurgical processing and recovery of metals. The key to success for this process are reagents which have suitable operating characteristics. One of these important characteristics is a relatively fast phase separation rate in the extraction and stripping circuits, as this greatly affects the size of plant required. A test for measuring phase separation rate is needed to help evaluate liquid ion exchange reagents. Such "a test also would be useful for evaluating carrier solvents that are used for diluting the re-agents. In fact, one standard test method would be very desirable as it would provide a common basis for comparing reagents and sol-vents. The phase separation test described in this paper has been used successfully for several years with the copper reagent, LIX®64N. The test is set up for feed liquors containing low copper concentrations. For other types of systems, modifications in procedure probably would be necessary. However, this test and the associated apparatus could be the basis for a standard phase separation test.

Jan 1, 1972

By Jacques B. Wertz

Recurring movements remotely connected with the Murray fracture zone and the San Andreas fault complex, together with the slow northwestward drift affecting the Baja California peninsula, could progressively have accentuated the tensional situation already connected with the anticlinorium in southern Arizona. From the fragmentary data gathered on the Texas lineament, it appears that a very mild curvature, concave to the northeast, may be present along this belt throughout Arizona. Those localities where the successive changes in direc¬tion of the strands of the lineament belt seem to occur do generally coincide with intersections of both north-northwestern and northeastern breaks. It is along the outward, southern fringe of the belt (at such structural centers like Bisbee, Baboquivari, Ajo) that the greatest impact of regional movements could be expected to have occurred through tangential-torsional stresses. Although it si accepted that the north-northwestern and more particu¬larly the northeastern fractures in Southeast Arizona are propitious to or partially responsible for mineralization, it seems undeniable that the Texas lineament belt must have greatly increased the potentialities for ore throughout the Arizona copper province. While intrusive bodies occur near major intersections, with the Texas lineament belt as a common denominator, it seems, the ore deposits are to be found close to one of the intrusive stocks, varying in distance from contiguity (Bisbee) to one or two miles away (Silver Bell orebodies).

Jan 1, 1970

By James J. Scott

I welcome this opportunity to speak before the Coal Division of the AIME in such an attractive setting as the Pacific Northwest. With the development of the Centralia project, the Pacific Northwest will have its first major coal-fired thermal electric generating plant. This State has a long history of coal mining that diminished with the passage of coal-fired steamships and locomotives but is now reviving with the growth of electrical power demand. Because this 1,400 row plant is to be supplied with surface-mined coal, it is particularly appropriate that this area be the setting for a talk on factors influencing the growth of surface coal mining in the West. During the course of my talk, I will touch on a number of factors including electric power demand, coal resources, production trends, environmental considerations and trends in State and Federal activities that I feel will influence surface coal mining in the West. Total electric power consumption by the year 2000 is expected to reach 9.4 trillion kilowatt-hours. Predictions of total coal consumption for electric power generation by that year range from a low of 845 million tons to a high of 1,520 million tons, or 2.6 to 4.7 times the amount used for this purpose in 1970.

Jan 1, 1971

By Malcolm Scoble

This contribution examines the motivation and prospects for mining companies to become Learning Organizations and integrate Lifelong Learning into their culture. Mining Schools have a potentially central role to play in developing Learning systems for access by industry. Reference is made to initiatives to develop a system that is based on collaboration between UBC, Edumine and the Canadian Institute of Mining, Metallurgy and Petroleum. Recent experiences with this model are reviewed.

Jan 1, 2005

Sinter mixes of three iron ore types were prepared with a range of water contents in a laboratory investigation. The mean diameter of the granulated mixes and the void fraction of beds of the mixes were determined experimentally. Pressure drop measurements over a range of flow rates were made in a laboratory permeameter with pressure tappings at several depths in the bed. The Ergun equation was applied to the results to determine the shape factor of the granulated mixes. The pressure readings down the bed were used to estimate the local void fraction in the bed using the Ergun equation and the calculated granule shape factors and it was found that there was a decrease in void fraction with depth in the bed. The significance of this and the variation of the shape factor values with the amount of water used for granulation is discussed in relation to the strength of granules of the sinter mixes.

Jan 1, 1984

By Steve Kral

Borates are minerals that contain boron. Trace amounts exist in rocks, soil, water and people. Boron-containing ores are rare and U.S. Borax, a subsidiary of Rio Tinto Borax, controls one of the world’s two world-class borate deposits. Through its global systems of mines, refineries, ports, sales offices and distribution centers, the company supplies nearly 45 percent of the world’s demand for borates. Borax has been mining borates in California for more than a century. This year the company celebrated 131 years of continuous business in the Golden State and 76 years at its operations in Boron, the site of California’s largest openpit mine. It also has mines and refineries in Argentina, refineries and ship-ping facilities in Europe and technical staff in the United States, North and South America, Europe and Asia Pacific. So, with the 130±years of borate mining and processing experience behind it as well as its global marketing and distribution centers, there is very little that Borax does not know about borates.

Jan 1, 2003

By V. Adamek

The specific lithological conditions over the Pittsburgh coalbed, highly resistive limestone and sandstone units with relatively shallow overburden, prevent the use of any predictive method as developed for European conditions. This paper describes the development of a subsidence precalculation methodology suitable to the mining-geological conditions in the Northern Appalachian Coal Field. It has been found that due to lithological conditions over the Pittsburgh coalbed the subsidence coefficient varies within the area of the subsidence trough. This is different from the European conditions where the subsidence coefficient is considered to be a constant. The effects of lithology, in-the form of a variable subsidence coefficient, have been separated for each test site by introducing a correlation between hypothetically homogeneous overburden and existing lithological conditions, while providing for different mining conditions. Field data from eleven Bureau longwall panel studies were used in the regression analysis. For each panel the characteristics of the variability of the subsidence coefficient along individual profile lines were defined. Regression analysis of the subsidence coefficients from all test sites on the location relative to the edge of the panel has yielded a third degree polynomial equation with a coefficient of correlation of 0.9999. All sensitivity tests have shown good results.

Jan 1, 1985

Stillwater Mining Company (SMC) has an extensive history with tunnel boring machines (TBM) at the Stillwater and East Boulder underground PGM mines in Montana. The most recent TBM used is for the Blitz Project, where a 5.5m (18ft) diameter main beam unit, commissioned in Q3 2012, is being utilized to drive a 6,975m (22,500 ft) ventilation and haulage level East of the Stillwater Mine for the Blitz expansion project. The assembly/commissioning of the TBM, institution of the planned diamond drilling program, application of ground control systems, and the current tunneling metrics will be covered.

Feb 23, 2014