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By Byron C. Hardinge, Michael Sokaski, Paul F. Sands, W. Loring III Mc Morris, David J. Akers

INTRODUCTION In the early days of coarse-coal cleaning by the dense-medium process in Europe, loess was one of the materials used for medium solids. Newly developed cyclones were used to reclaim and thicken the loess suspension. On occasion, when the cyclone thickener at the Maurits mine in the Netherlands plugged, the overflow was found to be filled with clean coal free of impurity. From this observation stemmed the concept of the cyclone as a cleaning device. Development took place during World War II in the laboratory of the Dutch State Mines under the direction of M. G. Driessen. A 15-tph (13.6 t/h) pilot plant was in operation in the laboratory by 1945, when, in September, Driessen made the first public disclosure of the process in a paper presented to the Institute of Fuel in London.51 In April 1945, operation of this pilot plant was observed by H. F. Yancey, who was so impressed with the potential of the cyclone process that, on his return to the United States, a research program on the cyclone was immediately started by the US Bureau of Mines (USBM). This work led to an AIME paper in 1946 in which the first details of cyclone operation on American coals were made available.52 Commercial adoption of the cyclone proceeded in Europe, initially in the Netherlands, Germany, and France. In the United States, where coal is less costly and most of the coals are easy to clean and respond well to simpler cleaning processes, the first cyclone plant was not built until 1961.53 THEORY Before discussing the theory of a dense-medium cyclone, a brief description may be helpful to some readers who are not familiar with its basic operation. In a typical dense-medium cyclone, illustrated in Fig.7-51 a mixture of medium and raw coal enters tangentially near the top of the cylindrical section, thus forming a strong vortical flow. The refuse moves along the wall of the cyclone and is discharged through the underflow orifice. The washed coal moves toward the longitudinal axis of the cyclone and passes through the overflow orifice, or vortex finder, to the overflow chamber. Washed coal is discharged from this chamber, usually through a tangential outlet.

Jan 1, 1991

By D. R. Gehring

Effective project management is an excellent technique for meeting a goal through set, well-defined objectives. Even though project management is successfully used throughout the world in various construction projects, underground mining has unique characteristics that require approaches that vary from classical project management theory. Typically, a project includes four main stages: definition, planning, implementation and control. Definition and planning are often the most overlooked stages, but are arguably the most important. This paper addresses practical techniques for the definition and planning of projects for underground construction.

Jan 1, 1996

By J. P. Rider

Along with increased production from longwall units has come the likelihood of increased worker noise exposures. In recent years, equipment has become larger, more powerful, and noisier than its predecessors. For these reasons, the Mining Division of the National Institute for Occupational Safety and Health (NIOSH) is investigating worker noise exposure on longwall faces and researching possible solutions to reduce this exposure. Part of this research effort involves studying the effect of covering the underside of longwall shields with acoustical material to reduce reverberating noise along the face. Experiments using acoustical absorptive insulation to cover the undersides of the shields, shearer body, and the shield supports were conducted at the full scale simulated longwall test facility located at the Pittsburgh Research Center. Sound levels were recorded every l.5 m [5 ft] along a 15.2 m [50 ft] section of the simulated face for all of the conditions tested. The analysis of the data indicated that a 2.0-3.0 dBA noise reduction was achieved between the shearer drums and a 4.0-5.5 dBA attenuation was attained upwind of the headgate drum.

Jan 1, 1997

By J. P. Fitzgerald

This paper is an accumulation of information on the geology, mineralogy and mining of the Hectorite clay deposit owned by NL Chemicals (U.S.A.), Inc. The mine is located in San Bernardino County, California approximately 35 miles east of Barstow and 1-1/2 miles south of U.S. Highway 40. The region is known as the Mojave Block which is a region bound by the San Andreas fault zone to the southeast and the Garlock fault zone to the North. The faults of both zones are active, vertical faults along which movements are mainly horizontal. Most of the faults within the Mojave Block are high angle faults which trend northwest. They are considered part of the San Andreas fault system and are a result of the right- lateral movement characteristic of this system. The east-trending faults are also high angle faults, along which movement has displaced rock units vertically. Manix fault is the only mapped fault that shows evidence of left slip which is characteristic of the Garlock sys tem to the North.

Jan 1, 1986

By Lee W. Saperstein

The SME Research Council assists SME and its constituencies in establishing research directions that will benefit the mining industry and its professions. It also provides information about these directions to its membership, to government and to related industrial societies. The 1995 Research Forum, organized and chaired by George Luxbacher, was the second in a series of meetings organized to develop these directions. A copy of the full proceedings is available from SME for $12 plus postage and handling. The first research forum (Saperstein, L., 1993, "Technology for the Future, MINING ENGINEERING, Vol. 45, No 11, November, pp. 1382-85) invited mining industry representatives to discuss the unsolved technical problems that were keeping the industry from greater economic and environmental efficiency. The second forum asked academic researchers to discuss the same general topics from their perspective. It came as no surprise that, in general, the two sets of presenters tackled the same problems. There was no surprise when the academics spoke of the need for fundamental long-term research. What may have been surprising was the number of university people who spoke for near-term research that leads to measurable economic returns or savings. The closure of the US Bureau of Mines (USBM) has changed the objectives and attitudes of the SME Research Council. From being a point of liaison between SME and USBM - a conduit of items from each party to the other the council is now much more on its own. This isolation presents opportunities and hazards. The opportunities are exciting because the council could be the focus for mineral industry research policy if it were properly structured. The hazard is obvious - if there is no bureau, it could be argued, why maintain the council? Many people believe that SME should take the first course and become the beacon for research policy. More than ever, money is being spent on minerals industry research by the federal and state governments - particularly at the mineral-oriented land-grant universities - by industry and by consortia among these groups. SME could be at the hub of these programs. There is a general concern that industry is less able to maintain an economic edge by means of geologic discovery. According to Titley, there will be fewer major, new world-class discoveries except, possibly, at the continental and tectonic-plate margins. Consequently, economic advantage will go to those companies and nations that stay ahead technologically. Given the inevitable diffusion of technology, it can be concluded that technology development, underpinned by research, must be continuous to maintain profits. This is a change from earlier years when change would occur in relatively rare major steps that were interspersed with extended periods of technological equilibrium. Over the fiscal years 1994 to 1997, there has been a 24% cut in research spending by the Department of the Interior (figures from the American Association for the Advancement of Science). This is the largest budgeted percentage cut in research funding of any federal department. Even so, there is still a substantial amount of federal research funding expended in the mineral and extractive-energy industries. The US Geological Survey, Environmental Protection Agency, Departments of Defense and Energy and others expend substantial funds on minerals industry research. Industry - producers and manufacturers - is also spending large sums on research and research-like activities. This activity argues that there is a role for SME's Research Council. Providing focus Consortia. The closure of USBM has resulted in the migration of expertise to consulting firms and to other entreprenrutisl research entities. Many of these groups are creating ad hoc consortia among themselves, nearby universities and industrial partners. The Research Council is well placed to provide an open forum for these con¬sortia. Presentations of research results, as went on in the annual meetings of the Generic Mineral Technology Centers, can help to establish an. archive of results and an avoidance of duplication of research. A continuing sense of research directions can evolve. National Science Foundation. No discussion of consortia would be complete without mention. of the National Science Foundation's (NSF) programs for Industry/University Cooperative Research Centers (IUCRC) and Grant Opportunities for Academic Liaison with Industry (GOALI). NSF is aware of the gap in federal support of science and technology caused by USBM's closure.

Jan 1, 1997

"There’s no fast way to add more than four miles of track, most of it underground, to the Sound Transit Link Light Rail system in the Seattle area. But increasingly busy traffic through a number of neighborhoods made it necessary. That’s the challenge a joint venture of several tunneling contractors faced when starting its portion of the $1.9 billion Northgate Link Extension in 2013, and the project is still keeping them busy three years later. Completion will mean just a 14-minute ride from Northgate to downtown for an extra 60,000 passengers by 2030. The transit lines will join 58 km (36 miles) of new and under-construction light rail lines running north, east and south from Seattle.Voters, tired of long commute times, approved the project, a key part of Seattle’s regional mass transit system, in 2008. The extension is part of a plan adopted by the Sound Transit board in 1996 to connect the region’s major activity centers. The Northgate project is meant to relieve one of the area’s most congested traffic areas by connecting the Northgate, Roosevelt and University District neighborhoods to existing routes including downtown Seattle and SeaTac airport.Sound Transit dedicated more than a quarter of the project’s estimated expense — $440 million -— to general contractor JCM Northlink LLC to handle the tunnel segment. JCM is a joint venture formed in 2013 between Jay Dee Contractors of Livonia, MI, Frank Coluccio Construction of Seattle, WA and Michels Corp. of Brownsville, WI. The contractors regularly collaborate on large-scale projects and brought experience working on a different section of the extension they completed in 2013.JCM project leaders knew immediately that the schedule would be demanding. They had to work around the clock, six days a week to meet deadlines. The extension runs through highly populated areas, meaning contractors had to follow strict city noise restrictions between 10 p.m. and 7 a.m. Plus, supervisors needed to manage the scheduling of nearly 250 employees to keep work running smoothly.“We had eight different operations and four different subcontractors trying to work in one tunnel,” said Chris Wood, JCM site project superintendent. “It’s important that we keep work linear. That’s the biggest challenge: keeping a path in and out so you can pour concrete, keep electricians and carpenters going, and accomplish everything else.”"

Jan 6, 2018

By Gregor de Ratmiroff

Field prospecting for bauxite in Venezuela has had a long but interrupted history having till now oferred but evidence of occurrences. The Venezuelan Government, trough the Corporación Venezolana de Guayana (C.V.G.), in 1974, formalized a major effort in prospection for bauxite in the Shield area and the Orinoco Delta in orden to establish the possibility of raw material supply to an upcoming and expanding aluminium industry. The Corporation, in turn, created and delegated to the Division of Geological Stu- dies, the formulation of the necessary infrastructure and execution of work in orden to determine the existence of economically exploitable bauxite deposits.

Jan 1, 1979

By T. Peter Philip, Erich U. Petersen, William J. Tafuri, Donald M. Hausen, Douglas N. Halbe

Scarcely a month goes by that I or someone else at Newmont Mining or Newmont Gold isn't asked to give a talk on the topic I was asked to discuss today. Investors, financial analysts, geologists, metallurgists, even our government--everybody wants to know what the future holds for gold mining. Well, you're not going to get exactly what you asked for. Today, I'm prepared to focus primarily not on what the future will bring to us, but rather on what the future will demand from us. More than that, I cannot undertake because it isn't within my scope to predict how wise and resourceful everyone in our industry will be in the future. What our future will hold, as I see it, will depend on our--and our colleagues'-- responses to these very real demands. Three critical issues stand out in my mind as to what the future will demand of us in the gold mining industry. And these demands will be for: 1. The very greatest of technical expertise and innovation. 2. The highest order of environmental sensitivity and timely accommodation. 3. Planning, planning and more planning. All of these flow inexorably today from the traditional objective of any mining company--or any company in any business, and that is, to make money. Nothing as I see it, should be undertaken by a geologist, metallurgist or even an environmental department, unless the exercises will enhance profits; and nothing may be ignored which can have consequent damage to the bottom line. Thus, the three issues I've listed for you subordinate themselves to the objective of making money, although at least in the environmental area, it might seem to some that we can only incur additional costs without even a dollar-for-dollar return. I hope to disabuse you today of any such out-of-date notion. Let's tackle the first issue-- Technical Expertise and Innovation. Newmont Gold Company this year is celebrating its 25th anniversary of successful and profitable operations on the Carlin Trend. Carlin in 1961, which is when exploration began on the "Trend" by Newmont, actually may share a lot of similarities with Carlin today. They didn't then know where the gold was and, if they found it, they had one hell of a challenge mining and processing ore at a profit because gold was selling at only $35 an ounce. Today, we know where the current reserves are. But we don't know where our future reserves lie. Furthermore, we don't know exactly how we're going to mine them, and, as everyone here knows too well, we don't know what the optimum metallurgical treatment is, even if we can find and mine them. And all that despite the abundant level of modern experience and skills within the current generation of mining companies, and the fact that, even taking inflation into account, gold sells at a higher price today than in 1965 when Carlin began operations. But, of course, I'm telling you what you already know.

Jan 1, 1990

By James S. Redpath

"The ways of the world be many and most of the ways be tried, you follow in the footsteps of others till you come to the great divide". These words, written by Robert Service a long time ago, come to mind when I think of our original attitude upon entering into a contract with the International Nickel Company to sink the deepest shaft in the world outside of the Union of South Africa. This shaft was to be sunk to a depth of 7,137 feet from surface, and while it was recognized by all concerned to be a somewhat unusual undertaking in our part of the world, the fact that quite a few shafts had already been sunk to this depth in South Africa probably gave us the feeling that we were following in the footsteps of others. In retrospect, because this shaft was being sunk under entirely different conditions than those existing in South Africa, we were in fact venturing into an entirely new area of endeavour without properly recognizing this fact. It has occurred to me that others considering a similar type of job could benefit from our experience, especially in an assessment of the risks involved and how they compare to those encountered in an ordinary shaft. For comparison purposes, I would define an ordinary shaft as being sunk to a depth of 5,000 ft or less, and a deep shaft as one being sunk to a depth of between 5,000 ft and 8,000 ft. The sinking of the Creighton No. 9 Shaft has been de-

Jan 1, 1997

By Xinyang Yu

The flotation of diaspore, kaolinite, pyrophyllite, illite and the diaspore-kaolinite mixture were studied with a new cationic organosilicon quaternary ammonium collector entitled QAS222. The acting mechanism of the collector with the four minerals was analyzed by Zeta potential measurement and FT-IR spectrum analysis. The results indicate that the QAS222 was effective in the reverse flotation of the diaspore-bauxite mixture of different Al2O3 -to-SiO2 mass ratios (A/S ratio) at an optimum pulp pH of 11. The potentials of the four minerals increased when they were conditioned in the QAS222 solution; however, the potentials of the three aluminosilicate minerals increased faster than that of the diaspore, especially at pH>9. Furthermore, they were positive in a wide pH range, indicating that QAS222 has a strong adsorption on the surface of the aluminosilicate minerals and thus that these minerals can be floated. The FT-IR spectra analysis further indicates that, besides electrostatic adsorp-tions, formation of the hydrogen bond and ammonium absorptions, chemical adsorptions occur between QAS222 and the aluminosilicate minerals, which allow for the QAS222 to be strongly adsorbed on the aluminosilicate minerals. However, these reactions between QAS222 and diaspore at pulp pH=11 are weaker than those of the aluminosilicate minerals. Thus, surface adsorptions cannot be formed effectively, resulting in reduced floatability.

Jan 1, 2010

By Chee Theng

"What do you think are the most important topics in mineral processing today? It is a question that begs to be asked when more than 100 of some of the best and brightest in Colorado mineral processing and their invited guests are gathered in one room. They are there for the 66th Annual Colorado MPD Meeting held at The Broadmoor in Colorado Springs: three days of finely curated talks and social events where participation was strong, and information was exchanged and connections forged in a relaxed, informal atmosphere.Water, tailings and social licenseNot surprisingly, water management, with the associated issues of tailings and social license, was high on the minds of those present. The Mount Polley and Samarco tailings dam failures have had repercussions across the industry. “There are big challenges with respect to tailings, and social and environmental pressures to find better ways to treat them,” said Steve Hearn of Huntsman Corp., a view echoed by Bob Kilborn of Kilborn Group LLC. Metso Minerals director Keith Butler said, “Water conservation is a key issue today. Many mining activities are now located in remote areas, so it has social and economic impacts on mining operations.” For Brian Olson of Samuel Engineering, wastewater and reclaimed-water treatment is interesting.Fittingly, the first talk of the meeting was on dry stack tailings by Michael Blois of Takraf USA, who went over both the advantages and disadvantages. “The average now is over one tailings dam failure a year,” Blois said, “and that is one too many.” But the technology may not be the right fit for all projects. In his talk on the KSM project, Jay Layman, president and COO of Seabridge Gold, showed how it isn’t practical for KSM and how Seabridge reached the decision on a cyclone sand tailings managementfacility as the preferred management strategy.The luncheon keynote also dealt with a tailings pond spill, but of a different kind. Bob Schafer, chief executive of Eagle Mines Management, spoke on the federal missteps that led to the spill into the Animas River from the Gold King Mine, a mine that had been a dry mine throughout its life and up to the 1990s."

Jun 1, 2016

By M. C. Rockwell

There are about 1.8 Mt (2 million st) of discarded dolomitic-limestone tailings from the Gays River lead/zinc mining operation in Nova Scotia currently stockpiled in a tailings pond at the mill site. Neutralization effectiveness similar to an agricultural grade limestone and low contents of residual metals make the tailings a potential source of soil conditioner material for the local market. However, the fine particle size, 98% passing 147 pm (about 100 mesh), and a moisture content of 20% make their handling, shipping, and application to soils difficult. The tailings were agglomerated into small hard pellets with various amounts of soil nutrients, moisture content less than 13%, and pH values ranging from 6.5 to 8.7.

Jan 1, 1987

By B. I. Pålsson, H-Å. Häggblad, J. F. Stener, P. Jonsén

"Understanding mill charge motion is important. In the charge, the center of gravity is shifted from the rotational center of the mill system, and its motion is induced by rotation of the mill. At the same time, the charge creates a torque in the mill system. Breakage of ore particles and wear of liners/ball media are closely linked to this motion. To study these phenomena in a physically correct manner, numerical models for different parts of the mill system are needed. Validations of such models are scarce, because of the difficulty of measuring inside a tumbling mill. Experimental measurements in a lab mill were done for a number of load cases: varying feed material, mill filling, mill speed and pulp liquid. The mill is set up to measure the charge-induced torque. The accuracy is good, with relative uncertainty less than ± 2% for relevant load cases. A full three-dimensional numerical model of the whole mill is used to predict induced torque. Agreement between predicted and measured torque at steady-state is good. In addition, the model can accurately predict the mill startup behavior for torque and mill power. This proves that the model is physically correct, and can be used for modeling large-scale mills.IntroductionUnderstanding of the charge motion within the mill is of importance in mill optimization. The breakage of ore particles and the wear of liners/ball media are closely linked to the charge motion. To study these phenomena in a physically correct manner, appropriate numerical models for different parts of the mill system must be used. Validation of these models is of major importance. This has led to an increased interest in obtaining an accurate and direct measurement of mill load and the behavior of the mill charge.For structural analysis, the finite element method (FEM) is the most developed and most frequently used numerical method. FEM is a numerical solution method based on continuum mechanics modeling. A constitutive relation for the actual material is described, and the governing equations are solved in Zienkiewicz and Taylor (2000). Varieties of different constitutive models for a large number of materials are implemented in modern FEM code. The computability of nonlinear problems in solid mechanics is investigated in Belytschko and Mish (2001), among others."

Jan 1, 2015

By M. Hodgson

The redox reactions that occur on pyrrhotite and pentlandite in contact with oxygenated deionized water were examined using voltammetry. Reactions were put forward in which both minerals were progressively hydroxylated to form thermodynamically metastable surface intermediate products. These intermediates were modelled as metal deficient sulphides where a sulphurous layer was coordinated onto the remaining metal sites via polysulphides. Prior to hydroxylation pentlandite exhibited changes in the surface stoichiometry which were not related to pH effects. The formation of polysuiphide-sulphur intermediates were believed to promote collectorless; flotability for the two minerals. Microflotation tests (0.3 g samples) verified that the surface potential and particle size affected the flotation response, excessive oxidation inhibiting the minerals' flotability. Larger scale tests using ore samples (30 g) confirmed that the extent of pulp oxidation, particle size distribution and the presence of frothers affected the flotation response, the findings being in accordance with the postulated model for the hydrophobic species generated on the pentlandite and pyrrhotite surfaces.

Jan 1, 1985

By M. A. Kaufman

In this paper I will attempt to present an up to date review of the type of exploration' that has previously been carried out in Alaska, discuss some of the more significant past producers and recent discoveries, and suggest some approaches to future exploration. Hopefully this information may be of some use to those parties tempting to evaluate Alaska's non ferrous, non placer, metal potential or contemplating initiation of exploration in the state. II. SUMMARY AND CONCLUSIONS Past production of non ferrous metals from lode deposits in Alaska has been meager considering the size of the state. Since there have been no major lode mines operative in Alaska since World War II, and since logistical conditions vary throughout the state, it is not possible to generalize with respect to mining costs in Alaska as compared to those in other areas. There seems to be little question, however, that a major deposit situated in a reasonably favorable location' could be profitably operating at present. Host of the known metal prospects in Alaska were discovered by early gold prospectors prior to World War I. From World War I through World War II exploration consisted chiefly of surface prospecting by prospectors on a diminished scale, as compared to the early gold rush days, drilling of some prospects by the U.S.B.M,, and occasional mine or prospect evaluations by mining companies. From the end of World War II to the present time, there has been a generally steady increase in exploration by mining companies consisting chiefly of prospect and district evaluations, large scale aerial reconnaissance programs in search of color anomalies, and regional drainage geochemical surveys. The post World War II increase in mining company exploration has not been matched by an increase in conventional surface prospecting.

Jan 1, 1972

By John A. Cordes, Thomas F. Torries

INTRODUCTION Nonfuel mineral markets have always tended to be volatile due to the cyclical nature of demand and the difficulty of fine-tuning capacity and output levels. Experiences over the past two decades, however, have been especially perverse. This short volume attempts to provide insights into this era and some guidance for the future. The papers are linked together by their focus on issues of productive capacity. At the same time, they provide a useful description, explanation and evaluation of the industry's evolution and its implications for the near-term. The regnant pessimism of the 1980s was very much alive during the early months of 1987 when the theme of this symposium was formalized. Indices of real metal prices had only inched-up from all-time lows in 1986. The hemorrhage of corporate red-ink was still a powerful memory. Frustration with the apparent inability of closures and reduced capacity utilization to re-establish market balance was strong. To the more pessimistic, the industry appeared destined to a quarter century of persistent excess capacity and nonremunerative prices. The conditions to support this pessimism were readily apparent. Economic literature tells us that surplus capacity is a complex, usually unexpected and often long-lived phenomenon caused by the interaction of at least three factors. The first is a rising capital-intensity of production. The second is the presence of aggressive new entrants whose capacity additions are typically (1) trade- dedicated because local market absorption is low; (2) cost-competitive for natural or policy-support reasons; (3) heavily burdened by debt-repayment obligations; and (4) viewed as important sources of employment, regional development and foreign exchange. The third, and often decisive, factor is an unanticipated decline or stagnation in demand growth for the sector's output. The first two factors combine to increase competitive pressures and to raise the actual or perceived cost of idle capacity. Market rigidity reduces responsiveness to price signals and distorts the burden of adjustment. Demand atrophy exacerbates these pressures especially on unprotected producers in the higher quadrants of the global supply function. In the mid-1980s, evidence of the existence of all these factors were easy to cite. Culprits were often identified. Claims for protection, global sharing of adjustment burdens, and imposition of disincentives to new capacity regardless of inherent economic status were co-dominant themes with the buzz-words of "competitiveness" and "level playing fields." This, notwithstanding the suggestions of the same economic literature that excess capacity persists longest when interventionist remedies permit it to continue. Today, only eighteen months later, the mood is decidedly more buoyant and most analysts are cautiously optimistic about the next few years. Many informed analysts have concluded that the excess capacity of the recent past has disappeared. For the present, the marketplace seems to have restored a balance between supply and demand. That the adjustment took five or six years longer than anticipated attests to the dramatic structural changes which have characterized the industry. The implications of these changes for the future are unclear. Were the macroeconomic shocks, coupled with industry transitions, so extraordinary in magnitude and timing that experiences were unique? If so, the next years may hold more stable and cautious times for the industry. Alternatively, is the inherently volatile metals industry facing a future of cycles equally perverse in terms of amplitude and duration due to economic uncertainities and inflexible industry response capabilities?

Jan 1, 1989

By M. E. Poad

The Research and development review arrived too late to appear in the May issue. The competitiveness of the US mining industry in a world market depends on many factors. The introduction of new and innovative methods, though, can have a significant, long-term impact. As industry cuts back its own long- term research and development efforts, the federal government continues to provide the major support for mining and minerals research. The US Bureau of Mines works with the mining industry and the academic community to develop innovative concepts for the mining and processing of non-fuel minerals. The Bureau’s research focuses on exploration and mining technology, minerals and materials science, processing technology, health and safety and environmental technology. Mine design A conical caving system, being designed by the Bureau, would allow the development of low-grade ore bodies, early startup at lower initial capital costs and increased safety and versatility in development and production. This method is a form of mass caving that allows the ore to be drawn from a central loading point at the bottom of the cone- shaped caving zone (Fig. 1). A simulation laboratory model and computer analysis show initial promise for predicted performance. For tabular, flat-lying ore deposits, the Bureau is investigating a version of the Finnish slot-and-fill system. For this total extraction method, a pattern of rectangular panels is laid out. One panel is extracted in a series of parallel slots and is replaced by alternating-row pillars of backfill. After one panel is mined, equipment and operations are transferred to another panel. By transforming this rectangular layout to a curvilinear geometry, one continuous spiral can be mined without re positioning equipment. Instead of parallel slots and pillars aligned in a rectangle, the slots and pillars are arranged in a spiral.

Jan 1, 1992

By E. Yan, M. Mankosa, G. Luttrell

"During the past decade, column flotation cells have become widely accepted for upgrading ultrafine sulfide ores. However, the use of columns has been widely relegated to cleaner circuits due to their comparatively high selectivity derived from the use of wash water dispersed over a deep froth. High tonnage rates and low feed grades make using column technology in roughing and scavenger stages challenging due to the resulting size of the needed equipment. To specifically address this challenge, a new high-intensity flotation system known as the StackCell™ was developed. This technology makes use of a novel pre-aeration method coupled with froth washing to simultaneously provide improved flotation kinetics and selectivity. The novel aeration system provides efficient bubble-particle contacting thereby shortening the residence time required for particle collection. This article reviews the technical design features of this new flotation technology and presents recent data from in-plant pilot testing in a copper-sulfide application. INTRODUCTION Column flotation cells have become very popular in the minerals processing industry for cleaner circuits due to their ability to produce a high-grade froth concentrate via the use of froth washing (Luttrell et al., 1999; Kohmuench et al., 2004). The use of wash water minimizes the nonselective recovery of ultrafine impurities that are normally entrained into the froth product from conventional flotation machines. On the other hand, the unique design of a column cell typically requires a large tank volume. Column cells must be tall to ensure that the pulp residence time is long enough to offset their inherently slow flotation kinetics and to minimize internal mixing that is detrimental to overall cell performance. The tall design minimizes the total floor space required for the column installation, but substantially increases the foundation load. The large size of the column tank can also create issues during fabrication, transportation and installation. To address these concerns, the engineering team at Eriez Manufacturing developed a next-generation flotation technology called the StackCell?. This high-intensity flotation machine was designed to provide column-like separation performance within a very compact volumetric footprint. This article describes the key working features of this new technology and provides data from recent pilot-scale tests conducted in gold and copper-sulfide applications"

Jan 1, 2016

By John W. Lane

Climax Molybdenum Company, a Division of American Metals Climax, Inc., operated a hydrometallurgical plant* at Climax, Colorado from August 1966 through August 1968 to recover molybdenum from a mixed oxide and sulfide ore. The ore treated for this addition to the existing plant contained sufficient Molybdenite values to be mined for Molybdenite recovery alone, so that the oxidized molybdenum recovery could be regarded as a byproduct operation. Climax is located at an elevation of 11,300 feet. All process equipment, except thickeners, was enclosed in buildings. Annual snowfall is approximately 250 inches per year. Paved highways and rail service to the plant are maintained and kept open all year. Most of the employees live in the town of Leadville, which is approximately twelve miles from the plant site. The sulfide flotation plant handles 40,000 to 45,000 tons per day of ore. The mine is one of the world's largest underground mines.

Jan 1, 1971

By V. O. Tenorio, K. P. Hague

Mines are constantly trying to improve production processes by optimizing work cycles, reducing operational delays, minimizing costs, controlling equipment utilization, and preventing occupational hazards. Currently, advances in digital mining technologies within the concepts of 5G and Industrial Touch Internet are allowing better control and monitoring of underground mining equipment, with centralized control systems that unify data analysis for proper decision making. A wireless 5G-based platform for controlling and monitoring systems for underground mine operations can be designed over a comprehensive layout in where bandwidth selection, sensor location, Wi-Fi repeaters and power distribution are put together to build a successful supervisory system. In order to confirm the validation of these concepts, a case study is proposed for a medium-sized underground mine with a multi-level network which includes tablets managed by production supervisors, along with other data collection devices installed in semi-autonomous mining equipment, collecting, and distributing data in near-real time, with interconnection to support and services areas on the surface.

Mar 2, 2022