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By R. Jedrzejczak

Endako Mine is an open pit molybdenum mine located in the north central region of British Columbia, Canada, approximately 160 km. west of Prince George. Production for the latter part of 1992 is expected to average at 63,500 tonnes per day of which 27,000 tpd constitute the mill feed. This production is achieved with five 15 to 19 cu. yd. electric shovels, six Euclid R190 and two Unit Rig M120 diesel-electric haul trucks, and three 121;.1 inch electric rotary drills. There are three ore zones delineated into pit areas called the Endako, Denak East and Denak West. Present mill feed source is the South East stage of the Endako Pit while the stripping is carried out in the South Wall stage also of the Endako Pit. The mine high grade aggregate is reduced in the primary and secondary crushing circuits before processing in conventional RM/BM/flotation circuits. The majority of the Molybdenum Sulphide (MoS2) is roasted on site to produce technical grade Molybdenum Oxide (MoO3) while a portion is further refined and treated to yield a 99.9% pure Molybdenum Sulphide (MoS2) "Ultrapure" product.

Jan 1, 1993

By D. Triantis

This paper presents the results of laboratory experiments for the detection of electric signals from Fiber Reinforced Polymer (FRP) sheet samples which have undergone a temporally increasing loading of bending type up to fracture. Electric signals that were recorded while the sample was subjected to bending are referred from now on as Bending Stimulated Currents (BSC), in order to differentiate them from the relevant signals emitted by materials that suffer uniaxial compressional stress. The latter signals are referenced as Pressure Stimulated Currents (PSC). BSC emitted from FRP sheet samples presented here, were recorded after applying three successive load steps to samples. The increase rate of applied stress was about 0.15kN/s. Initially starting from low load values to higher load values until the FRP sheet reaches at a state just before its failure. The BSC records from FRP samples are compared to equivalent recordings from cement mortar beam and distinguishable differences are discussed.

Jan 1, 2006

By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

The Mesabi Range extends continuously from near Grand Rapids, on the Mississippi River, E.N.E. for a distance of about 1120 miles to near Birch Lake, where it is covered by the large gabbro flow which forms the base of the Keweenawan series. The same formation (Mesabi) appears again near Gunflint Lake on the international boundary, and shows as far east as Thunder Bay on the north shore of Lake Superior. Between Mesabi station, on the Duluth and Iron Range Railway, and Birch Lake, although considerable exploration work has been done, there is no evidence of concentration of ore in workable bodies. The Gunflint beds are thin alternating layers of chert and hematite. Alt the workable deposits at present known, on the Mesabi, lie between Mesabi station and Grand Rapids, the greater number being St. Louis County simplified geologic column is given herewith instead of the complete correlation table given by the United States Geological survey.

Jan 1, 1920

By Rick Sarkisian, Albert D. Bonneau, David Keech

The Drummond Co. Inc.'s Shoal Creek Coal Mine Slope Belt Conveyor transports 5000 mtph (5500 tph) of material over a length of 1400 m (4600 ft.) and a lift of 3609 m (1180 ft.). Four 1500 kW (2000 hp) motors power the 1830 mm (72 in.) Goodyear Flexsteel 5800 steel cable belt. In May 1993, Dodge Manufacturing was selected to design and build the conveyor pulley assemblies for this conveyor. The conveyor includes five pulley assemblies. The 2135 mm (84 in.) diameter by 2135 mm (84 in.) face primary and secondary drive pulleys were designed for a resultant belt load of 3060 kN (688,000 Ib.) This paper describes the design and manufacture of the two drive pulley assemblies. Design details included are component evaluation, material selection, locking assembly selection, bearing selection and lagging selection. Manufacturing details include material procurement, welding process, lagging installation and component assembly. Quality control procedures are also discussed.

Jan 1, 1996

By Karl E. Elers

The term "potash" denotes a family of minerals and compounds of potassium, containing greatly varying percentages of that element. In commercial usage, most of the potash products are used in agriculture, where they are used to furnish potassium, one of the three basic elements for plant growth; the other two being nitrogen and phosphorus. Potassium's contribution to plant life is principally as a stalk strengthener, and if soils can no longer supply this basic element, then crop failure is inevitable without nutrition supplied from fertilization. While agriculture uses some 95 per cent of the potash produced, other industries require highly refined potash, for the manufacture of soaps, dyes, pharmaceuticals, synthetic rubber, insecticides, photographic film, and other products. Until the mid-nineteenth century, world agriculture had three options related to the potash content of soils: 1) crop rotation and pasturing to attempt to minimize the loss of potash in harvesting, 2) abandoning depleted and exhausted soils (part of the reason for the vast migration of populations in Europe and Asia), and 3) burning forests for the use of the ashes, and concentrating the nutritional value by boiling the ashes in large kettles, for "pot - ash". With the discovery in the mid 1800's and exploitation of potash from underground deposits in Germany, the beginning of the modern potash industry was established, but American potash requirements remained substantially dependent on German production until the 1920's, when oil drilling in the Permian Basin of New Mexico

Jan 1, 1972

By K. H. McDaniel

The Waste Isolation Pilot Plant (WIPP) is adding a third fan to operate in parallel with, and supplement, its two existing main fans. An engineering analysis conducted in 1995 identified the need for improved system availability and efficiency. The WIPP, located near Carlsbad, New Mexico, is a U.S. Department of Energy (DOE) Carlsbad Area Office facility designed to permanently dispose of U.S. defense-generated transuranic waste in a deep bedded salt deposit. Engineers at the WIPP performed a feasibility analysis for either modi tying, supplementing, or replacing its two main mine fans. Since the centrifugal fans were installed in 1988, multiple operational and performance concerns have been identified. A comprehensive engineering study was conducted (McDaniel, et al., 1997) to: identity and quantity operational concerns, evaluate possible alternatives, and recommend an optimum solution. The study indicated that adding a third single-duty centrifugal fan similar to the two existing fans, and equipping that fan with Inlet Van Controls (IVCs) was the best choice. This alternative provided the most desirable combination of operational readiness, and improving system performance. The fan installation project accommodates several operational and scheduling constraints. WIPP is scheduled to receive waste in May 1998. This milestone is proceeded by an operational readiness review. Fan installation could not be allowed to compromise the WIPP's ability to declare facility readiness and had to minimize operational disruptions during the system tie-in. All engineering for the project is completed and physical modifications started in July 1997. The project was completed in 1998.

Jan 1, 1999

By John S. Lagarias

When ore bodies are faulted or mill feed turns refractory, mining managers and engineers act vigorously to convert imminent failure into eventual success. The recent proliferation of onerous "environmental" regulations and restraints is likewise a threat to successful mining enterprise, in some ways more insidious and dangerous than the problems presented by natural obstacles. The regulatory burden has become so heavy that a pall of pessimism covers much of the mining enterprise. In this paper we frankly recommend a Pollyanna approach, making not just "the best of it" but directing the whole environmental process: first, to improve our planning, engineering, and operating procedures; and, second, to demonstrate the need for modification of laws and regulations which are intolerably burden-some to both the mining industry and the public. It is customary for government officials and environmentalists to point out how great are the new environmental regulations and how successfully these have improved the natural environment in particular and the quality of life in general.

Jan 1, 1978

The Waste Isolation Pilot Plant (WIPP) is adding a third fan to operate in parallel with, and supplement, its two existing main fans. An engineering analysis conducted in 1995 identified the need for improved system availability and efficiency. The WIPP, located near Carlsbad, New Mexico, is a U.S. Department of Energy (DOE) Carlsbad Area Office facility designed to permanently dispose of U.S. defense-generated transuranic waste in a deep bedded salt deposit. Engineers at the WIPP performed a feasibility analysis for either modifying, supplementing, or replacing its two main mine fans. Since the centrifugal fans were installed in 1988, multiple operational and performance concerns have been identified. A comprehensive engineering study was conducted (K. McDaniel, et al., 1997) to: identify and quantify operational concerns, evaluate possible alternatives, and recommend an optimum solution. The study indicated that adding a third single-duty centrifugal fan similar to the two existing fans, and equipping that fan with Inlet Van Controls (IVCs) was the best choice. This alternative provided the most desirable combination of operational readiness, and improving system performance. The fan installation project accommodates several operational and scheduling constraints. WIPP is scheduled to receive waste in May 1998. This milestone is proceeded by an operational readiness review. Fan installation could not be allowed to compromise the WIPP's ability to declare facility readiness and had to minimize operational disruptions during the system tie-in. All engineering for the project is completed and physical modifications started in July 1997. The project will be completed in early 1998.

Jan 1, 1998

Two key strategies for a new generation of mining are developing domestic raw material production and doing so in an environmentally responsible way, according to presenters at the 83rd annual meeting of the SME Minnesota Section in Duluth (the 71st annual University of Minnesota Mining Symposium). From technical sessions detailing how to build com-munity support, to a short course on international perspectives in iron ore mining and processing, the two-day meeting emphasized the potential of Minnesota state deposits and the importance of maintaining productive community relations both locally and globally. The meeting of more than 300 mining industry professionals began on April 20 with a traditional convocation celebrating the values of northern Minnesota. The accompanying tradeshow, with a record 131 booths, showed the speed and vigor of the economic rebound. Keynote speaker Scott Anderson, vice president and senior economist at Wells Fargo, stated the prevailing mood of the conference: ?Wow, what a difference a year makes.? With metal prices and sales up and heading higher, he said, it was clear that the production-centered economic recovery is reaching the mining and the minerals industry. However, Anderson sounded a few notes of caution. Serious threats to economic stability remain, including the burgeoning national de?cit, high unemployment and the still out-of-control foreclosure crisis. Overall, he predicted a below-average recovery and stressed the importance of developing a long-term business strategy.

Jul 1, 2010

By Ekkehart Mertins, Hans-Dieter Wasmuth

During the last years many new concepts have been presented for magnetic separation of feebly magnetic minerals by using the new high-duty permanent magnetic material especially in Open Gradient Magnet Systems (OGMS). In this respect KHD Humboldt Wedag AG developed an improved version of a drum-type magnetic separator called PERMOS® with a special magnetic field configuration for the NdFeB permanent magnets, which gives a magnetic field strength of at least 0.7 Tesla and a wide working zone outside the drum. The magnet system within the PERMOS® unit is no longer made of relatively large magnet blocks of alternating radial magnetisation; the system is now made up of a multitude of small NdFeB bars with a specially oriented magnetisation. This PERMOS® Open Gradient Magnetic Separator can be used for dry magnetic separations in "top-feed" and 'free-fall" feed configuration as well as in the conventional wet "drum-type" feed mode. It allows high throughput rates of up to 40 metric tons of solids per hour and meter of drum length without any clogging problems, even when strongly magnetic com-pounds are present in the feed material. The important design features and the actual machine characteristics of the improved PERMOS® units for dry and wet magnetic separation are described and typical examples for their commercial application for industrial minerals and for martitic iron ores are presented.

Jan 1, 1995

By Victor F. Hollister

This first section of case histories of mineral discoveries, Vol. 3, covers some of the milestones in porphyry copper and skam exploration successes. It was during the era of these discoveries that large, complex exploration departments emerged as permanent adjuncts of large mining companies. The discoveries helped shape how and where exploration activity was conducted. Probably the most important factor in exploration success is management. Few management people are mentioned in this section or in any exploration history, yet the distinction between success and failure ultimately rested with the decisions they made. One of the most successful groups was initiated by Roger Straus and Herbert Brownell when they sought to make Asarco into an important metal producer. Relying on Clem Pollock and L.H. (Bill) Hart to identify and push worthwhile projects, the Asarco management remade the company. Asarco will benefit from exploration successes com- pounded by that team for years to come. Duval is an example of a management that decided to add metal production to its industrial minerals output. When Page Morris was president, that company opened three major porphyry copper mines and became an important factor in metals. Under the Monis management team, Duval became a leader in exploration. At the other end of the scale are managements that snatched defeat from the jaws of victory and by so doing changed the character of their companies in other ways.

Jan 1, 1991

By M. K. LeBegue

Water sprays located behind the bits of cutter drums have been shown to reduce the incidence of face ignitions. This paper details the design approach to successfully incorporating water seals into a drum miner cutter head.

Jan 1, 1999

By Stephen P. Signer

The U.S. Bureau of Mines is developing an intelligent system for roof' control that uses both an expert system and neural networks to improve the capability of mining engineers to evaluate roof support effectiveness for ground control in coal mines. The expert system com- pares roof support capacities with the support requirements estimated to be necessary to maintain entry stability. It does this by evaluating the results of tests on various types of roof support and establishing the maximum allowable load according to anchorage capacity and yield strength of the support. After the user enters geological information (rock properties, geometry of the opening, in situ stresses, bolt pattern parameters, etc. ), the expert system compares the predicted required loading to the roof support capacity and gives the operator advice on the adequacy of the design and how improvements could be made. A good source of the real-time data necessary to allow the expert system to make decisions will come from a roof bolting machine being developed by the Bureau of Mines. Researchers have collected data from a Western coal mine on drill bit position, penetration rate thrust, torque, and rotation rate. Using this information, two neural net- works were developed to identify different types of strata and features in a mine roof such as rock type, rock compressive strength and joint characteristics. The result is a system that can assist a mining engineer with design information that can be constantly updated as mining progresses.

Jan 1, 1992

By K. D. Luxbacher, J. T. Davis

"A wind tunnel was designed to examine air flow, heat transfer and layering near an active fire at a working face. This tunnel simulates an active entry in an underground coal mine including an attached cross-cut of similar dimensions. A steel rectangular duct 1 ft. (0.305 m) tall, 3 ft. (0.914 m) wide and 10 ft. (3.05 m) long composes the main body of the tunnel and represents a mine entry. Air flow is generated by an exhausting centrifugal fan attached to one end of the crosscut. This fan was sized to supply air velocities based on Froude scaling. A 6 in. (15.25 cm) propane burner is used to simulate fires of various heat release rates at the working face. Thermocouples are used to map heat layering in the tunnel. Ports are installed for the introduction of tracer gases into and from sampling the system. Barometric, differential pressure, and temperature sensors are also included to monitor environmental conditions. Details about the design and testing of the system are presented including an overview of how the tunnel was scaled to accurately represent fire and flow phenomena. Finally, the proposed use of the tunnel for better understanding of mine fire phenomena and prevention is given. INTRODUCTION Fires in underground mines have been a concern since the dawn of mining. While technological advancements, regulations and best practices have improved both fire detection and firefighting techniques, mine fires continue to represent high risk events. From 2006 through 2015, fires accounted for 1.06% of fatalities in underground coal mines and 0.85 percent of fatalities in all underground mines in the United States (U.S. Department of Labor, 2006 to 2015). In addition to the risk of loss of life, mine fires can cause millions of dollars in equipment damages and lost production revenue. Extensive research has been conducted on how fires occur and spread in underground mines. In addition to testing conducted by government agencies such as the Mine Safety and Health Administration (MSHA) and the National Institute for Safety and Health (NIOSH) (e.g.(Liming, 2006), researchers like Verakis and Dalzell (Verakis, 1988) and Lowndes, et. al. (Lowndes, 2004) have furthered this field by studying ignitions and propagation of conveyor belt fires. While the studies of belt fires in mines are extensive, studies focused on fires at the working face are few in number. The particularly confined space and limited access to a working face, coupled with less robust, temporary ventilation controls create a unique environment that warrants special attention. Separate from studies on mine fires, the use of tracer gases to characterize flow patterns in normal mining ventilation is well established. In 1982, Timko and Thimons (Timko, 1982) outlined current and future applications of sulfur hexafluoride (SF6). However, little experimentation has been conducted to study specifically how tracer gases might be used to evaluate active mine fires and the fires’ effect on the surrounding mine environment (e.g.(Lindsay, 2014). In order to better understand the dynamics of smoke layering from a fire in an enclosed space, a small-scale apparatus was designed to map smoke layering and to examine other aspects of fire behavior at a working face. In addition to studying smoke flow around an active fire, experiments will be conducted using tracer gases in order to determine how they might be used to evaluate an underground fire."

Jan 1, 2017

By Bruce C. Trent

The need for effectively evaluating the potential for surface subsidence due to under- ground mining has been widely documented. As the emphasis within the coal mining industry changes to reflect the increasing demand of this resource, the potential for damage due to differential surface subsidence will certainly become more acute. The present state-of-the-art of predicting ground motion due to underground excavations is, at best, primitive when one considers the immense complexity of possible geological inter- actions. For the most part predictions have been limited to empirical evaluations based upon earlier case histories. While the tools of the subsidence engineer are limited, they are important and serve to provide reasonable bounds for possible ground motion. As underground mining becomes more extensive, however, there will be many instances where excessive subsidence will be most undesirable and yet there may be few, if any, case histories similar to the operation in question.

Jan 1, 1982

By R. P. King

Direct observations of intergranular fracture during comminution are very difficult to make. The best indirect method is based on the measurement of interphase area before and after comminution. If intergranular fracture does not occur, the interphase area should be conserved during comminution, but it should decrease if significant amounts of intergranular fracture occur. The interphase area per unit volume can be determined by image analysis from measurements on sections of the unbroken ore and on sections through the particles after comminution. However, the measurements must be corrected for the effects of image resolution on the measured phase and particle perimeters. A correction procedure was developed, and the true interphase perimeter per unit volume was measured before and after comminution in a sample of chromite-serpentinite ore and two samples of Witwatersrand pyritic quartzite. The pyritic quartzite showed no significant evidence of grain- boundary fracture while the chromite-serpentinite showed a significant decrease in interphase area per unit volume of chromite, indicating that intergranular fracture occurred.

Jan 1, 1992

By A. M. Al Taweel, S. M. El Mofty, T. A. Hassan, M. R. Moharam, A. M. Ramadan

The axial mixing characteristics of a pilot-scale flotation column were investigated with the objective of identifying means to mitigate the extent of axial mixing that adversely affects its grade/recovery performance. A wide range of design and operating conditions was investigated and the experimental results, obtained using the dynamic response method, were analyzed using three axial mixing models. The dynamic response of the column can best be described using the axial dispersion model. The results obtained suggest that the value of the axial dispersion coefficient, EL. can be signi6cantly reduced by judicial selection of hydrodynamic conditions and/or the use of column inserts that suppress the onset of hydrodynamic instabilities inherent to the operation of conventional flotation columns. Up to 40% reduction in the value of EL was thus obtained by using spargers that produce more uniform bubble sizes, while up to 30% reductions were obtained by controlling the residual frother concentration.

Jan 1, 1995

By W. E. Foreman, A. Hayatdavoudi, A. Ghalambor

The objective of this investigation was to determine the sensitivity of three selected input parameters in the operational control of continuous bottom fed thickeners used for the treatment of coal refuse slurries. The three variable parameters were "Feed Flow Rate," "Feed pH," and "Feed Solids Concentration." These three input parameters were studied under three cationic-anionic polymeric conditions. For each polymeric condition, two mathematical models were developed, one for overflow response and the other for underflow response. The combination polymers produced the best quality of overflow and underflow. For this polymeric condition, change in the feed solids concentration was the most sensitive factor in the maintenance of the overflow quality, and the feed pH was the most sensitive factor for the maintenance of underflow quality. The mathematical models generated a set of plots that would allow an operator to control and/or adjust any of the three variables to achieve optimum conditions.

Jan 1, 1991

By Bruce T. Stanley

Though most porphyry-molybdenum deposits lend themselves to various reserve estimating techniques, still there must exist the constant effort to not merely obtain an estimate but rather to obtain the best estimate. To answer the challenge of a complete ore reserve estimation, one must attack the problem with the purpose of obtaining the results closest to reality. What we wish to determine is simple: metric tons (short tons), grade, and kilograms (pounds) of molybdenum contained. In order to effectively accomplish this task, further consideration must be given to the ease of using the information obtained and its inherent reliability. The only known method for ore reserve estimation that supplies the needed results along with its distribution and a measure of confidence provided by sound mathematical backup is geostatistics. The following review is an example of geostatistical application of an ore reserve estimate at the AMAX Henderson mine demonstrating technique, viability, and usefulness of results.

Jan 1, 1979

By James L. Hendrix, R. Y. Wan, David W. Kappes, Jinrong Zhang, M. C. Fuerstenau, Terence E. Albert

A sulfidic flotation tailings ore, containing 1.14 gpt Au and 242.53 gpt Ag, was treated by low temperature chlorination roasting followed by cyanide or chloride leaching. Eighty per cent of Ag was recovered by cyanide leach when the ore was roasted at 350°C with 50 kg/ton calcium chloride. About seventy per cent of Au was made cyanide amenable by chlorination roasting at 400°C. A better Ag recovery, ninety per cent or over, was achieved by chloride (NaCl+HCl) leach. However, Au recovery was very poor by chloride leach. Ferric chloride, calcium chloride, and cupric chloride were compared as chlorinating agents for their effect on Au and Ag recovery. The study found that low temperature chlorination roasting is very effective for recovering Ag associated with stibnite and stannite. The best chlorinating agent for the test ore was found to be calcium chloride. Parallel roasting-leaching tests indicated that chlorination roasting was far superior over oxidation roasting for both gold and silver recovery.

Jan 1, 1993