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By S. G. Zahony

The Moris gold deposit resides in a massive ridge-forming sulfide-poor epithermal quartz and calcite vein system and consists of a mineable reserve of four million tons of 2.1gm Au/ton. Post-mineral normal faulting along the hanging wall of the main fissure has caused a hogback-like exposure of the vein, allowing for inexpensive opencut mining. The vein formed between pre-Cretaceous(?) phyllitic clastic sedimentary units in the footwall and Tertiary andesitic volcanic rocks in the hanging wall. Part of the ore reserve is hosted in a Tertiary conglomerate that rests unconformably atop the phyllitic footwall sequence. The original unoxidized vein material contained substantially less than 1 gram Au/ton. A four-fold upgrading of gold occurred by enrichment when gold recrystallization took place in the electric fields of oxidizing pyrite cubes.

Jan 1, 1993

Thermal pretreatment can significantly improve industrial comminution operations by reducing energy requirements and increasing mineral liberation. The effect of pretreatment using conventional and dielectric heating followed by quenching on the fracture properties of a number single and multiphase brittle materials has been investigated. The reduction in the impact fracture energies and particle strengths with and without pretreatment has been measured in precise single-particle experiments using the Ultrafast Load Cell. Variations in the fragmentation pattern caused by different pretreatments were assessed by measurements of the progeny size distributions. The differences in the effect of thermal treatment on single and multiphase materials are discussed based on the experimental results.

Jan 1, 1995

By C. D. Harrison

This paper presents the results of 18 high-G centrifuge tests performed at the Electric Power Research Institute's Coal Cleaning Test Facility in January 1985. These tests, using -28 mesh (0.6mm) froth flotation product, show that the high-G, solid-bowl centrifuge can produce clean-coal moistures of less than 12 percent at solids recovery rates exceeding 98 percent. The high-G centrifuge achieved these low moistures by applying centrifugal forces up to 2,000 times gravity. Because these forces are two to three times the forces used in a screen-bowl centrifuge, the high-G centrifuge can use a solid bowl and still produce a low-moisture product. The solid bowl captures ultrafines that would pass through a screen bowl, and thus obtains higher recovery rates than a screen-bowl centrifuge.

Jan 1, 1985

By J. A. L. Campbell

Peabody's Camoy mining system is a truly continuous conceptual method of underground mining of coal. The system solves the three factors which limit coal from being mined continuously. Camoy's principal features are improved productivity and increased recovery. A conservative retreat production rate of 2 1/2 times normal continuous miner room-and-pillar mining rates are projected for a 6-7' seam. Overall mine productivity will be 2 times normal, with a potential for considerably higher rates. Major incremental production increases can be achieved by partial implementation of the system. Total mine recoveries of 75% are expected. The system includes both advance and retreat mining. The retreat half of the approach encompasses many of the features of short wall mining. A central panel is prepared for retreat mining by driving entries using room-and-pillar mining to the left and right of it. The room-and-pillar mining encompasses the advance features of Camoy. In the retreat phase, the roof of the face is supported by self advancing chocks or shields. All mining is done under the chocks by a continuous miner. As the miner advances the chocks continuously move forward behind it. Thus, as in a typical short wall system, continuous roof support is attained. Ventilation is unidirectional, another characteristic of short-wall type systems. Fresh air is brought in and passed over the working personnel. It moves to the face where the continuous miner is operating, picks up the generated dust and released methane, and is exhausted away from all personnel. Exposure to respirable dust and ignition hazards due to methane build-ups are almost totally eliminated. Thus, the second limiting factor is overcome and continuous ventilation is attained. Coal mined with the continuous miner is passed to a surge car and then to a Serpentix conveyor. The Serpentix, a Peabody invention, is a flexible conveyor capable of going around corners.

Jan 1, 1976

By R. A. MacGregor

The Stanreck mine of Stanreck Uranium Mines Limited in located on Quirks Lake in the Elliot lake - Blind River area of Northern Ontario. It is approximately 25 miles north of the north shore of Lake Huron, equidistant between the cities of Sudbury and Sault Ste. Marie. The property was developed ad brought into production at a rate of 3,000 tens of ore/day during the uranium boom of the mid 1950's. By 1960 mine waters were becoming quite acid through the activity of bacteria. Treatment of this water was begun for pollution control and a small amount of uranium which had been leached from the ore by these acid waters was recovered. Development of bacterial leaching with a view to increasing production by this method commenced in December 1962. Subsequently, it was succeesfull in producing 10,000 - 15,000 lbs. of U308/month. Since late 1964 uranium production has been obtained solely from bacterial leaching. A rare earth concentrate was also made for its yttrium content during 1966 and 1967. This paper describes the development, operation and methods used in the underground bacterial leaching process.

Jan 1, 1969

By Alexander N. Winchell

"Location. The iron formation of the Gogebic district (including the Penokee) comprises a narrow belt south of the western part of Lake Superior extending from Michigan for a considerable distance into Wisconsin. From the mouth of the Montreal River (about twenty-five miles west of Ashland) the iron formation is only about twelve miles distant, but it is about twenty miles south of Ashland. Beginning on the east at a point about eight miles east of Wakefield, Mich., it extends through Sunday Lake, Bessemer and Ironwood in Michigan, and thence south of west through Hurley, Wis., and only a short distance south of Mellen, Wis. About eight miles westward from Mellen, the formation disappears, but six miles further west it is known to reappear and continue thence for about eight miles. The total length of the range is about sixty miles, two-thirds of this distance being in the State of Wisconsin; but nearly all of the ore has been obtained from the eastern third of the district, which is in the State of Michigan.History. This iron range was first noted in 1848 by Dr. Randall, assistant geologist to Dr. David Dale Owen, while following the fourth principal meridian northward. It was also reported by Charles Whittlesey in an account of a survey made in 1849, and published by Owen in 1852. Analyses of the iron ore are given with the following account. ""The bed of magnetic iron ore south of Lac des Anglais is of extraordinary thickness,25 to 60 feet. * * In the wild and deep ravines where the Bad River breaks through the range, there is a cliff of slaty ore * * * probably three hundred feet thick. * * * I estimate more than one-half of this face to be ore, and in places the beds are from ten to twelve feet in thickness, with very little inter-mixture of quartz * * * . The position of the best exposures of ore which I saw is such as to require from eighteen to twenty eight miles of transportation to reach the lake."""

Jan 1, 1920

By Setareh Afrouz, Emily Sarver, Cigdem Keles

The resurgence of severe lung disease among US coal miners since the mid-1990s has led to efforts to better characterize and monitor respirable dust exposures, particularly focusing on mineral constituents from rock strata surrounding the coal. A rapid analysis method for silica (quartz) mass using direct-on-filter Fourier transform infrared (FTIR) spectroscopy has been developed, which can also estimate kaolinite, a primary silicate mineral in many coal mines.

Feb 24, 2022

By R. C. Emmett

Waste treatment in the mining industry is by no means a new problem to this field. In a sense, the entire process from ore to finished product is one of waste treatment - the separation of a relatively minor quantity of desired component from valueless material. Where it has been necess-ary or economical to practice conventional waste treatment or pollution control methods, such as dust collection, water recovery from tailings, or impounding of residues for future treatment, this has been done. Generally the containment of hazardous pollutants such as arsenic and cyanide also has been followed in modern times. But it is only recently, with the public outcry for the elimination of all forms of pollution, "that the industry has been forced to solve what often appears to be a myriad of difficult and costly waste treatment problems, or be faced with the alternative of closing down the operation. It is the objective of this paper to describe new as well as conventional approaches to these problems, specifically as might be applicable to liquid-solids separation methods. Host wastes in the industry are present either as solutions or slurries, or can be most advantageously handled by conversion to this form, such as in scrubbing noxious gases and dusts with water. Separation of the solids and purification of the aqueous effluents are, therefore, often the principle problems.

Jan 1, 1971

By E. R. Palowitch

On February 5, 1973, Eastern Associated Coal Corp began shortwall mining in their Federal No. 1 Mine, thus marking the first attempt in the United States at modern shortwall mining, i.e., using a continuous miner to extract coal open-ended from pillars 100 to 200 feet wide, under the protection of a self¬-advancing roof support system (1)1/. Since then, four additional shortwall faces have been operated. While the number of face-years of shortwall experience in the United States is limited, this experience has been anything but uniform. Differences in operator motivation, coalbed parameters, geologic conditions, panel dimensions, and face equipment all have contributed to a wealth of knowledge which can provide guidance for the design of future shortwalls. The purpose of this paper is to review the history of shortwall mining in the United States and to assess its value to the U.S. coal industry in terms of the health and safety of the miner, the percentage of coal recovered, coal production, worker productivity, and relative cost performance.

Jan 1, 1976

By H. R. Coles

Test work conducted in the 6.4 and 10.52 m Aerofall Mills at the Iron Ore Company of Canada Carol Project showed that the conventionally used ?deflector?-type liners which form the basic principle of Aerofall Mill grinding did not necessarily provide the best grinding performance. A new design, using low profile liners incorporating radial ribs of a proper height, actually improved the mill throughput in the order of 9 to 20% without sacrificing grinding efficiency. In addition, the new design reduced liner weight and scrap losses, which resulted in a reduction of liner consumption by 25%. It provided better protection to the mill shell and reduced the overall maintenance cost for the mill

Jan 1, 1980

By Gerald H. Luttrell

The determination of mass balances is the first step in analyzing the performance of processing circuits. Although conceptually very simple, the mathematics associated with mass balances can be cumbersome when conflicting data sets and/or complex circuits are evaluated. Fortunately, many of the spreadsheet programs available today include powerful search routines which can be adapted to solve common mass balance problems. To demonstrate these capabilities, a generalized mass balance program has been developed using the Microsoft Excel? spreadsheet. Compared to commercial programs, the spreadsheet format is user-friendly, more versatile and easier to customize. This paper reviews the mass balance problem and describes how spreadsheet tools can be used to reconcile conflicting data.

Jan 1, 1996

By B. Mishra, Q. Shi

Numerical simulations have been used to investigate roof fall in the past decades. Comparing to the continuum based methods, the discrete element method has been well recognized for its excellent performance in simulating large strain problems and fracturing processes in the rock mass. However, the discrete element method has its limitations. When simulating a large-scale problem, a large number of particles are required, which consumes significant computational resources. In the present study, a 3D numerical model coupled with the finite-difference method (FDM) and the discreteelement method (DEM) was created to simulate the laminated roof failure in an eastern coal mine in the US. In the FDM-DEM coupled model, the laminated roof of the entry is represented by an assembly of bonded particles using PFC3D. The laminated roof is simulated by adding parallel discontinuities. The discontinuities are given certain stiffness and strength in the model. The ribs, floor, and far-field surrounding rock are represented by continuum zones using FLAC3D. The strength of the discontinuities is varied sequentially and the fracturing of the laminated roof was analyzed with respect to entry advance. The results showed that the laminated roof fractures along the discontinuities while an intact roof fractures in a dome shape. Increasing the strength of discontinuity could enlarge the tensile zone inside the laminated roof and hence change the crack distribution. In addition, the crack quantity in the laminated roof behind the advancing face decreases with the increment of discontinuity strength while this trend is not occurring ahead of the advancing face. The simulation demonstrated that coupled method using PFC3D/FLAC3D can reproduce the laminated roof failure in underground coal mines.

Mar 2, 2022

By N. Wahl, D. M. Blackketter, R. Thornton

This paper evaluated using a water-filled abandoned mine (Orphan Boy) as a heat source for a 240- kW closed-loop heat pump with the goal of heating a 2,000-m2 building. The mine has a 245-m vertical shaft connected to a large stope by three horizontal cross-cut shafts. There is 1,250 x 106 L of water at a consistent temperature of 24-26° C that is available mostly in the stope. The only heat exchanger placement option is in the vertical shaft. Therefore, the focus was to model heat exchanger placement in the vertical shaft to determine the extent to which the systems will induce thermal currents between the stope and vertical shaft. Modeling of thermal currents, temperature profiles and heat contribution from the ground was done using finite difference and computational fluid dynamics. An optimal configuration was determined showing sufficient water movement and heat transfer will occur with a low water temperature in the shaft above 20° C. This project supports a U.S. Department of Energy (DOE) grant that will implement the full-scale system.

Jan 1, 2013

By B. Berg, J. Stephenson, J. Mansanti, C. Nyikos

"Intrepid Potash, Inc.’s Carlsbad East facility has refined sylvite and produced muriate of potash (MOP) since 1965. In addition to MOP, Intrepid Potash began recovering the mineral langbeinite from a mixed ore reserve in 2005. In 2011 a new langbeinite recovery process for the coarse (+850 micron) size fraction was constructed to enhance the overall langbeinite recovery. Based on the limited mixed ore reserve and an abundance of langbeinite ore reserves the transition of the East plant to a langbeinite only facility was targeted for 2021. Due to a decreasing grade of the mixed ore reserve, declining sales pricing, and high sylvite operating costs a strategic decision was made to accelerate this transition into 2016. To enable a successful transition, a fines recovery system needed to be developed, constructed and implemented. This paper describes the advancement of langbeinite processing at Intrepid Potash and the planning, development and successful execution of the transition to a langbeinite only operation. BACKGROUND Langbeinite (K2SO4·2MgSO4) is a double salt containing potassium sulfate (K2SO4) and magnesium sulfate (MgSO4). It is used as fertilizer and in the industry is described as Sulfate of Potash Magnesia. It is attractive as a specialty fertilizer and in addition to containing a ready source of a primary nutrient potassium, it also provides two secondary essential nutrients, magnesium and sulfur. It is especially attractive for chloride sensitive crops. Langbeinite has a specific gravity of 2.8, a Mohs hardness of 4.2, and is brittle thus very friable. It is the hardest of the saline minerals, and despite its relative softness on the Mohs scale can be very abrasive in process environments and in field applications, probably due to its conchoidal cleavage. Its solubility at 240 g/l is less than the solubility of sylvite (KCl) or halite (NaCl) and due to even slower relative dissolution kinetics washing with cold water has been a common practice for upgrading langbeinite ores. The solubilization/crystallization relationship for langbeinite is different from the majority of other evaporite minerals in that once langbeinite is solubilized it does not form langbeinite again. Instead it gives up one mole of magnesium sulfate, takes on various waters of hydration and precipitates out as either schoenite (K2SO4·MgSO4·6H2O) or leonite (K2SO4·MgSO4·4H2O) depending on temperature. Due to its partial solubility and phase transitions at its surface when exposed to moisture, there is strong cohesion between wetted particles; the resulting stickiness of the upgraded products can create significant materials handling issues unless processed in slurry form or at relatively low moisture levels. Langbeinite has been produced commercially from two locations, the Kalush and Stebnik regions in the Cartpathian Mountains of former Poland and now the Ukraine and from the Permian Basin in New Mexico (Garrett, 1996; Smith 1949). Current production is from two operators in the U.S., Mosaic and Intrepid Potash."

Jan 1, 2017

By Jenna Wundrack, Evan Thibaud

The advanced cryogenic treatment is a post-manufacturing metallurgical process that involves subjecting off-theshelf materials to extremely low temperatures, significantly improving wear resistance and reliability. These case studies explore whether the claims of Enrich Bits & Tools benefit metals and their specific in-field application to drill bits in the blasting industry. This paper reviews the application of the treatment to button drill bits for enhanced wear resistance in two operations. The first is a civil construction project with highly abrasive rock. To confirm the remarkable benefits of the treatment, a second case study was performed. This case study utilized measure-while-drilling technology in consistent rock characteristics to reduce variables in the field study.

Feb 1, 2024

By R. J. Sweigard

Deep tillage is used widely as a Means of alleviating excessive soil compaction. There has been some concern that the voids created by deep tillage may collapse before a more natural soil structure develops, resulting in recompaction subsequent to deep tillage. A laboratory investigation was conducted to determine the feasibility of pneumatically injecting organic material into the voids during deep tillage to prevent any significant recompaction from occurring. Various amendments were injected into the soil in the laboratory using a small-scale ripping and injection system. Measurements were made of selected soil properties to evaluate the feasibility of this method.

Jan 1, 1993

By T. W. Camm

"As engineers, we are trained to use logical, rational problem solving to insure our mines operate at maximum efficiency. We tend to use the same technical approach to design safety into all mining systems. This works well for machines, but not so much for the human component. Recent insights in the field of behavioral economics provide useful ideas for addressing the fact that we are driven by emotions more often than by rational thought. Understanding the nonrational aspect of human behavior is an important piece of any safety system design. INTRODUCTION The most common economic model is based on humans making rational decisions; that given the proper information, we will make a logical, rational decision based on what is best for ourselves (Ariely, 2009, p. xviii). In many cases this is an accurate description of how we make decisions. As an engineer, I was trained to apply the precision of mathematics and logic to solve problems. As an engineering professor, I now teach this approach to bright young minds preparing them for a life of professional effectiveness as practicing engineers. That said, we are not only rational. Daniel Kahneman, winner of the Nobel Prize in Economics, describes a model for how we think (Kahneman, 2011). System 1 is the part of our mind that is fast, intuitive, and emotional; while our logical, slower, and deliberative mind is System 2. According to Kahneman’s model, System 1 runs automatically, most of what you think and do originates in System 1. System 2 takes over when things get difficult, including the application of math and logic, and the resolution (or avoidance) of conflict. As engineers, we would typically assume that we operate in System 2 mode most of the time. This is where the model becomes useful, for Kahneman points out two important aspects of the dynamic between the two systems in our mind. First, System 1 has biases, systematic errors that lead to answering questions with an easier answer (rather than a right answer) before System 2 is engaged. Second, we can be blind to the obvious, and also be blind to our blindness. Complicating things further, System 1 cannot be turned off (Kahneman, pp. 24-25)."

Jan 1, 2015

By D. G. Ball

Other than being used to convey fill material for the gob stowage or building of ribside packs on advancing longwell faces, pneumatic conveying has not been used for the transport of materials on a large scale in mining operations. The technique is extensively used in the wood products industry for conveying wood chips, limestone and other ingredients for the manufacture of paper, for the transfer from railcars, barges or ships to silos or stockpiles and further transfer into the pulp mills. This method of material transfer has the distinct advantage of transporting suitable material over horizontal and vertical distances within the same system. In considering material associated with mining, this includes, ore, coal and rock up to 4 inch cubed size, throughputs of 200 tons per hour over horizontal distances of 3000 feet or vertical lifts of 2000 feet. In recent years tests have been carried out to determine the physical and economic limitations of pneumatic hoisting, the results of which have led to the installation of two fully productive coal hoisting systems at mines of the National Coal Board in Great Britain. The equipment used for the pneumatic hoisting of coal or waste rock is described in this paper, together with a brief history of the tests which led up to the installation of the two hoisting systems in Great Britain.

Jan 1, 1977

By R. E. Musgrove

At the present time Climax Uranium Company recovers vanadium oxide from carnotite type uranium ores in the mill at Grand Junction, Colorado, The flowsheet of this mill is shown in Figure I. Vanadium is solubilized by a salt roast of the slime fraction of the ore and dissolution is accomplished by a water leach. The metal is precipitated from the pregnant liquor as sodium polyvanadate by heating to boiling and adjusting the pH to 3 with sulfuric acid. The sodium polyvanadate, commonly called, "red caken, is filtered, melted, and cast into thin flakes. This fused flaked vanadium oxide is the material which is packaged for sale. Fused vanadium oxide, marketed by Climax, contains approximately 87% V205, 7% alkali oxide, 0.08% sulfur, 0.03% phosphorus, and less than 0.5% Insoluble. This material is of a lower grade and has a higher alkali oxide content than other vanadium products offered for sale at this time. A typical analysis of a high grade vanadium oxide currently offered for sale by another company is 98% V205, 1 - 2% alkali oxide, less than 0.05% sulfur and less than 0.2% Insoluble. The only reagent consumed in the precipitation of the sodium polyvanadate is sulphuric acid. The total reagent cost is 0.58 cents per pound of vanadium oxide produced.

Jan 1, 1958

By Susanne Pignolet-Brandom

Flash smelting products of a copper sulfide concentrate collected at successive levels in an experimental reactor have been studied by reflected light microscopy, scanning electron microscope - energy dispersive analysis and electron nicroprobe analysis. Chalcopyrite, intermediate solid solution, bornite, chalcocite, metallic copper, magnetite, iron-copper spinel, pyrrhotite, hematite, delafossite and cuprite have been identified in the product samples. The detailed reflected light microscopy study of these phases and their abundance in the samples has resulted in the identification of the series of reactions during flash smelting.

Jan 1, 1985