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By Lindsay Norman

To many who for years have scrutinized the US mineral supply picture, recent, often strident debate on present-day security of many critical mineral supplies echoes sentiments repeatedly expressed in the past decade by the minerals industry. At no time since the last world war has such a flurry of public concern been expressed for the economy's mineral sector. Where once mineral availability problems were relegated to the newspaper's business section or not reported at all, today comprehensive analyses of our international mineral posture are discussed in detail by some of the nation's most respected and widely read periodicals. In past years, disinterest was also experienced whenever the mining industry attempted to carry its message to Congress, the public, and the government's executive branch. Among minerals professionals, the past decade was a time of particular frustration clue to serious erosion ill US ability to competitively produce the vast array of raw materials vital to the economy acid national defense. Fervent calls for immediate attention were simply not answered. These professionals have understood that mining and agriculture are the primary sources of wealth, fulfilling virtually all needs and creating and sustaining jobs. Why then has it been so difficult to raise the consciousness of the American public, and even more surprisingly, of the government and national leadership? The answer to this question is perhaps endemic to how government functions, but pore important, it begs that mining professionals capitalize on the opportunity and the attention now at hand. Carefully conceived and implemented actions by both private and public sectors are needed more than ever before in the past 35 years. To this end, it is vitally important to seek out and resolve the root causes of supply problems and not dwell on superficial solutions. The following discussion attempts to establish a simple framework to view this process. It does not presume to be an exposition of cause and effect, but hopefully identifies some needed steps. Growing Awareness in the 1970s Of all events stimulating current concern, certainly the OPEC oil embargo has left the deepest impression. It was inevitable that after such a shock, man. Americans would begin asking whether the US was as vulnerable to cutoffs of minerals as it was to oil cutoffs. Then, when serious trade security questions surfaced in sonic mineral-rich nations in Africa and the Persian Gulf, the ominous term ''resource war" began to be heard. Countries such as South Africa, Zaire, Zambia, and Zimbabwe have suddenly become key areas for testing our national security resolve. As the US witnesses the influx of Marxist influence in many sub-Saharan exporting nations and the rising threat to free world access to critical materials and energy, the assurance of adequate supplies is becoming a national issue at last. The US is now learning that self-sufficiency for many vitally important mineral commodities has vanished. Of course, it did not vanish overnight; it had been leaking away for years, and the trend was noted by industry and a few in government. Within the minerals community, suspected weaknesses in America's resource posture were sought and found. As a result, the country's heavy reliance on foreign sources fur more than a score of minerals, many extremely vital to security, has been forcefully documented and the case for drastically altering the supply unbalance hits been proposed. The renewed concern for national defense is central to almost all proposals for minimizing US foreign mineral dependence. It is not surprising that many of the voices heard today on the dependency issue are active members or alumni of the militate establishment. Unfortunately, their almost total focus on the security aspects of dependency has tended to obscure important underlying issues which are not directly defense-related. Some of the proposals advanced might mitigate the deeps-dency problems, but they still fall short of curing the underlying problems that have led to a steady loss in mineral self-sufficiency. In almost all instances these problems call be traced to increasing government influence on the free market minerals economy. Some national security proponents seek to attain total self-sufficiency in minerals. Such arguments must he tempered by existing realities. It is easy to demonstrate that the US obtains substantial quantities of sonic essential minerals from potentially insecure sources abroad. That the US will continue to do so in the foreseeable future is not in doubt Uncertainty begins, however, when we try to interpret the significance of these facts. It is important to understand that mineral dependency does not irrevocably lead to vulnerability. Unlike oil, no mineral commodity combines the same degree of universal indispensibility and centralized foreign control of supplies. Moreover, although many US-required minerals are produced by fewer countries than export oil, those minerals cannot approach petroleum in economic or industrial importance. Finally, most foreign supplies come front friendly, secure nations such as Canada, 'Mexico, and Brazil. This, aid more, constitutes a vital element in US economic health as a world trading nation. The Cost of Interruption The US is currently stronger and more resilient than many expected after absorbing the oil embargo shock and subsequent price increases. Nevertheless, major worldwide

Jan 6, 1981

By K. J. Stanaway

Concentrations of minerals between 3.5 and 5 specific gravity such as ilmenite, rutile and zircon in large accumulations of sand constitute "heavy mineral" placers. Two fundamentally different modes of formation characterize "trap" and "bed" placer variants. Smaller and generally higher grade trap placers form during sediment erosion or reworking. Because of their smaller size, they rarely yield economic heavy mineral deposits. They become economic, either if they contain more valuable "heavies" such as gold, or, if they occur within or near much larger but lower grade bed placers. Bed placers form during sediment accumulation episodes in any environment and lithofacies where mineral supply and fluid dynamics are favorable. Three heavy mineral deposits are discussed to illustrate bed placer geology and how trap placers occur with and relate to them.

Jan 1, 1991

By C. Opoku-Ware, M. Kukay, P. Conrad, F. Inkoom, R. Pal

Researchers at Montana Tech are investigating the potential for developing trees tolerable to degraded un-reclaimed mine site tailings and soils as a solution to re-establishing long-term tree growth on those sites. This project involves growing tree seedlings from seeds planted in the degraded mine tailings and soils in which they will eventually be planted. The outcome of the project is expected to lead to a successful solution for re-establishing tree growth in degraded tailings and soils in Butte, Montana with minimal post-planting human intervention. Work conducted on the project to date has shown successful growth of seedlings in degraded tailings and soils. INTRODUCTION In an effort to improve Butte Area One natural resources, this research project is working to help restore tree growth in the Butte Priority Soils Operable Unit Boundary (BPSOU) (Opoku-Ware, et al 2018). Research by Blicker, et al (2003) found that, the BPSOU, which is part of the Silver Bow Creek/Butte Area National Priorities List (Superfund) Site within and near Butte, Montana has multiple historic mining sites situated entirely within the urban setting of Butte. Mine wastes and mill tailings, accumulated from over 100 years of gold, silver, and especially copper mining are dispersed throughout Butte, posing health risks to human and environmental receptors. Stabilization of tailings sites is needed to control fugitive dust, prevent run-off of toxic material resulting in subsequent sediment deposition in streams, reducing the volume of water seepage through acidic and heavy metal contaminated material, and improving land productivity and aesthetic values (Watkin and Watkin, 1982). If successful, the project will help restore water quality and maintain stream flow in Silver Bow Creek where it flows through Butte Area One. Trees native to Butte are being grown to seedlings in a greenhouse located on Montana Tech’s campus which will be planted in degraded soils located within the BPSOU. Growing trees is expected to help restore vegetative ground cover within the watershed contributing to stream flow in Silver Bow Creek. The trees will prevent soil and tailings from eroding and being deposited in Silver Bow Creek where they could degrade water quality and choke stream flow. The project combines research with tree seedling growth to provide a resource for Butte that could produce thousands of tree seedlings each year adapted to the harsh climate, soil, and tailings conditions that exist in the BPSOU where they will grow. It is anticipated that the trees developed by the project will have the capability for long-term survival and growth because they will be germinated and grown into seedlings in the degraded soils and tailings collected from the BPSOU where they will be planted. Soils and tailings collected for the project have been evaluated to determine if they lack nutrients or contain substances potentially toxic to the long-term growth and survival of the trees. Toxic levels of metals, high concentrations of soluble salts, extremes in pH, nutrient deficiencies and imbalances, surface crusting, high bulk density, low infiltration rates, high surface temperatures, low cation exchange capacity, restricted microbial activity, low water retention, harsh climatic conditions and surface particle movement are some of the traits of mine tailings sites that restrict revegetation efforts (Barth, 1986).

Jan 1, 2019

By Dr. David R. Hargis

Finite-difference digital computer models can be used to evaluate the effects of proposed mine dewatering and depressuring operations on ground-water aquifer systems. The effects of proposed dewatering and depressuring operations can be simulated for both underground and open-pit mining in confined and unconfined aquifer systems. Design of dewatering and depressuring well arrays to accommodate proposed mining operations in a variety of hydrogeologic settings can be accomplished through judicious application of well-documented and tested computer programs that are widely available from government agencies and universities. The speed and flexibility of the computer models can provide an economical means for comparison of alternative mining plans, and can be used to determine the optimum mine plan with respect to dewatering requirements.

Jan 1, 1980

By C. S. Vender

Knife River Coal Mining Company's Beulah Mine is a multiple seam lignite operation located in western North Dakota. The mine began production in 1963 with annual production at 450,000 metric ton and now produces 2.2 mm ton. As development progresses, operations have advanced into more complex geologic areas. Various techniques have been analyzed to maximize coal recovery in a cost effective manner. Additional studies are on-going to determine what changes will be implemented as we encounter deep wet sands in the reserve area.

Jan 1, 1991

By M. Gershon

Four computerized approaches for coal blending are described and their strengths and weaknesses are explored. Spreadsheet analysis Other than word processing, spreadsheet software is the most commonly used software. Its wide availability and ease of use are two desirable features that have led many to try to adapt it to the purpose of coal blending. These are the two main advantages of this approach. To use a spreadsheet for coal blending, each row of data represents one source of coal. Each column represents a quality of the coal, with the last column specifying the tonnage of that coal in the blend. The calculated figures are the blended qualities, which can be programmed to appear in the bottom row. A trial-and-error approach is then used to develop the best blend. Inserting any blend in the last column provides the blend characteristics at the bottom of the page. If any specifications are not met, the blend can be changed, all calculations being immediately updated. This process is repeated until all specifications are satisfied. A third advantage of this method is that it is exactly the procedure that one would go through if doing this by hand. With a spreadsheet, many more blends can be evaluated in much less time, allowing the designer to try to improve over satisfactory blends to find the best of them. The resulting improved blends or cost savings are a fourth advantage of this approach. There is only one major disadvantage of using the spread-sheet. This is that most probably the best blend is not found. As an inexpensive introduction to computer-assisted blending, which can be easily understood and cost just a few hundred dollars, this is a recommended place to begin. Computerized search Computerized search approaches represent crude first attempts at letting the computer design the blend. Unfortunately, the blends found by these programs are very often less satisfactory than those developed manually. The way these techniques work is that they design, according to some predesigned pattern, a number of different blends and then quickly evaluate them. It is then straightforward to select the best from this sample set. The quality of the results depends on the number of blends designed, the way they differ from each other (the search procedure), the number of sources available, the number of quality specifications, and the severity of the specification limits. Good results are usually obtained for small, simple problems. At best, the results obtained are inconsistent from one blend to the next. Programs of this type are advertised in the mining literature. They usually mention how many different blends are evaluated, making it clear that this is more than can be tried manually. Expert systems Expert systems use a source of information known as a knowledge base. The knowledge base, usually a set of if-then rules, attempts to reconstruct the deductive reasoning process of an expert in some job capacity. For coal blending, the usual trial-and-error process has an easily recognized pattern of rules that are followed to try to find a better blend. By following these rules, it is possible to home in on the best blend without the exhaustive search required by the previous method and without the manual manipulation of the spreadsheet approach. The use of an expert system accomplishes this. One of the rules may say something like "if BTU is out of spec, then add more in the blend from a source having a high BTU and subtract some from a source having low BTU." In other words, it goes through the trial-and-error process. The process continues until all specifications are achieved and can continue further to try to optimize the cost. Of course, less simplistic rules are also needed. One set of rules would determine maximum changes in the tonnage added or deleted to the blend or from any one source. Other rules would be needed to determine which quality to improve if two or more are out of spec. At this level, the process of building the knowledge base provides the engineer with a deeper understanding of his or her own thought processes. The advantage of obtaining better blends is clear for this approach. Two more advantages should also be apparent. One is that it follows the same common sense logic that is used when doing the blends by hand or by spreadsheet, making it easy to understand. The other is that, like the search procedure, it designs the blend rather than just analyzing manually designed blends. Thus, it has all the good features of both approaches discussed thus far while providing improved results over each. A final advantage is the ease of use and ease of development. The expert system shells that are on the market are very easy to use and can be run on microcomputers. Linear programming Linear programming is an algebraic tool that solves a set of linear equations to yield an optimal solution to a problem. The optimal solution is based on the linear model so the results are only as good as the ability of the linear model to accurately portray the reality of the problem situation. It is fortunate for the coal blending problem that a linear model can be devel¬oped that reflects exactly the problem that is required. Unfortunately, the mining industry has been slow to use this tool. Coal blending applications available that use linear programming take one of three forms. The first, requiring exper-

Jan 12, 1988

By Wisecarver D. W.

Today the longwall is getting increasing attention in the United States as an excellent way to mine coal. This is not to say it is the best way in every mine because conditions, capital costs, and markets may well dictate another method. However, operators with working longwalls are often showing preference by phasing out room-and-pillar sections and replacing them with longwall. In the United States there are about 90 longwalls in operating coal mines and the number is increasing. In Europe, 95% of underground coal mining is by longwall compared with only 5% in the United States. In the Western States about 25% of the underground coal mines use longwall mining. There is logic behind the increase in longwalling. Compared to room-and-pillar mining, straight single-pass longwall has important advantages that show up in underground coal mining in any part of the country.

Jan 1, 1978

By Bill Kendall

"In coal mines, handheld air, electric and hydraulic powered drills are used along belt conveyors, in single entry development, in entries where there are obstructions, and in longwall recovering bolting. In hard rock mines, pneumatically powered jackleg drills are typically used in narrow vein mining. Drilling and bolting in narrow confines has traditionally been performed with pneumatically or hydraulically powered hand-held drills or newer electrically powered hand- held hammer drills due to their low cost, simplicity of operation, and extreme flexibility due to their small size. Mechanized equipment has typically been too large, too expensive, inefficient due to the confined space, and too restrictive due to lack of flexibility for use in narrow confines.Although the handheld equipment is effective, it requires operator exposure to certain inherent hazardous conditions in use. These include falling rock from the roof, rib and face; tripping hazards; bending twisting lifting hazards; high noise levels and chemical fumes from the pneumatic exhaust. The operation of the hand held equipment can adversely affect the long-term health of the operator - continual jackleg operation frequently results in longterm damage to hearing, shoulders, arms and wrist joints and back injuries. This results in a reduction in life style for the operator and higher personnel turnover rates for the mining company.Hand-held drills also typically have limited thrust and torque capability that limits their ability to push long resin bolts, inadequate torque to properly install resin bolts or to properly torque mechanical or tensioned rebar bolts. Hand-held drills do not offer any type of protection for the operator from roof or rib falls. They do not offer any means for handling roof or rib mesh. Since the operator stands on the ground the maximum safe drilling height without use of a ladder or "riding the drill" is limited to 2.44 m (8 ft)."

Jan 1, 2014

By William Hodder, Lisa Smiley, Ehsan Alav

The Don River & Central Waterfront Coxwell Sanitary Bypass Tunnel (CBT) Project in Toronto will extend approximately 10.5 km and be lined using a precast concrete segmental tunnel liner with an internal diameter of 6,300 mm and external diameter of 6,900 mm. The CBT liner was grouted through ports drilled in the segments. The Westerly Storage Tunnel (WST) in Cleveland will extend approximately 2.93 km long and will be lined by using a similar precast concrete segmental tunnel liner with an internal diameter of 7,620 mm and external diameter of 8,230 mm. The WST liner was grouted using both grout ports built into the tail can of the TBM and through segments. Each tunnel was mined primarily in shale with varying levels of weathering and both tunnels had dry and wet sections. This paper will document the means and methods for grouting in each tunnel as well as the methods utilized to proof grout and the results found.

Jun 13, 2021

By Stephen W. Denton

Planning a mining operation in Alaska will involve the investigation of many parameters common to mine planning anywhere. However, there are some unique circumstances that must be recognized when one considers development of mining operations in Alaska. This paper will not attempt to provide a blueprint for mine planning in Alaska, but hopefully will provide a better understanding of the truly unique nature of the northern latitudes. Given this understanding, the mine planner can better assess the potential hurdles along the road to a successful mining operation. The regulatory trend towards uniform standards for mining throughout the United States exemplifies the necessity for Alaska to prove its unique position in the natural resources picture. The factors which make Alaska truly different from the "Lower 48" can be summarized by four points 1) Remoteness and Size 2) Seasonable Extremes 3) Geologic Immaturity 4) Vegetation and Wildlife

Jan 1, 1984

By Ralph M. Stricklen

The need to move large tonnages of slurry has grown as mines have become larger. As existing tailing depositories are filled up, new mines developed, or environmental requirements dictate, it becomes necessary to transport tailing particularly over longer distances. A typical slurry transport system is shown in Figure 1A. Figures 1B, 1C and 1D show sketches of the system auxilliary components: feed box, receiving sump and drop box, respectively. There are two basic types of slurry transport systems, packed flow and slack flow. Packed flow is typified by a pipe running full; slack flow by a launder or pipe running less than full. Slack flow in launders or channels is also referred to as open channel flow. Generally slack flow slurry transportation involves a flow with less than 65 per cent solids, and there is an upper limit on particle size, depending on the slope of the system.

Jan 1, 1984

By J. Perlacia

Introduction The Bulk Handling Technology has already started its transformation to the Industry 4.0. Having some of the harshest working and environmental conditions of the industry, the possibility of remote analysis and maintenance of the components seems a perfect target to focus on. The most important and expensive tools have been adapted to the digital era during last years, from remotely controlled haul trucks to monitored conveyor belts. However, these big parts of the installations rely in smaller parts that have been left aside for a while, mainly due to the difficulty to adapt them to IoT (Internet of Things). The paradigmatic example is the lack of monitored rollers whereas all the other components of the conveyor belt installations (the belt itself, motors, drums etc.) were monitored some time ago. The main problem is that a failure of a single roller can cause the stop of the whole conveyor, due to the possible damages to the belt, thus the implementation of an integral monitoring system of all the components of the conveyor is a must. The R&D Department of ULMA Conveyor Components, has been working since early 2012 on the development of Monitored Rollers, facing all the problems until its final installation in very different demanding conveyors, from the Australian extreme heat to the freezing cold Norway. All the tests done under actual working conditions, in real installations, have given a valuable knowledge in the identification of problems, their solution and the final advantages of a roller monitoring system. Background and Current State The malfunction of a single roller in certain conveyor belts can suppose the standstill of the whole installation until its replacement, due to the risk of greater and more expensive failures like the rip of the belt. In the case of a bulk handling installation where a continuous supply of material is necessary, an unexpected stop of one hour could entail huge economical losses. What’s more, many conveyor belts are several kilometers long or the access to some parts of them is very complicated. Due to these difficulties the inspection and maintenance operations can become expensive and hard going, with staff going over the whole area checking the correct condition of the conveyor and rollers, which means a dangerous activity. As in many other industry products, the condition of rollers can be recognized measuring key parameters like the temperature of the bearings, the vibration level etc. The traditional way is to use the characteristic noise of a failing bearing, but this method usually implies to change several rollers because the maintenance team is not able to identify a single source of the noise. In recent years different attempts to measure the temperature of the bearings have been made, but the result is not accurate enough due to the proximity of the rollers in the idlers

Jan 1, 2019

By John K. Liu

The trend to larger grinding mills, requiring total drive power in the range of 10,000 KW(13,400 HP) or so provides the incentive for developing new power transmitting techniques, since conventional girth gears are limited to about 3700 to 4500 KW per mesh (5000-6000 HP). For the immediate future, the synchronous motor, with its beneficial power factor, and the squirrel cage induction motor, with its high reliability record and low maintenance, still promise to be the best choice for prime mover(s). Due to the abovementioned single mesh power limitation of the gear train, however, two or more motors must be combined to attain the required drive power. This paper describes a scheme for coupling these motors to the mill using a straightforward, essentially mechanical means that is based on proven components and controls.

Jan 1, 1977

By E. D. Gálvez, L. A. Cisternas, A. López-Valdivieso, F. Lucay

"The floatability of molybdenite fines in saline solutions was investigated through microflotation studies using a modified Hallimond tube. In addition, the effect of pH and gypsum precipitation from calcium ions (Ca2+) and sulfate ions (SO4 2-) ions in saline water on the recovery of the molybdenite was analyzed. It was found that the floatability of molybdenite fines significantly increased with the ionic strength of the saline solutions and is independent of pH above 0.5 mol/L ionic strength. The high floatability of molybdenite in saline solutions is explained as being due to the low electrostatic repulsion between bubbles and the edges of molybdenite particles, which is exceeded by interactions due to van der Waals and hydrophobic forces. The precipitation of Ca2+ and SO4 2- ions as gypsum had a detrimental effect on the natural floatability of molybdenite because of gypsum crystal attachment on the faces of the molybdenite particles. This precipitation phenomenon may be initiated in copper–molybdenite flotation circuits that use recycled saline water, like seawater containing Ca2+ and SO4 2- ions.IntroductionWater availability is a significant factor in mining projects. Water, particularly fresh water from rivers and underground water, is becoming a scarce resource for mining operations and new projects. Under these circumstances, the use of water with high concentration of salts in flotation plants is becoming increasingly important (Cisternas and Moreno, 2014). The use of seawater has been studied as a sustainable solution for many mining companies in dry areas located near the sea. Notably, using seawater in mining operations is how mining companies in Chile have coped with the problem of water resources (Cisternas and Gálvez, 2014). In 1930, small plants in Chile used seawater to float chalcopyrite from high-copper-grade ores. In 1975, the results of tests in pilot plants for the flotation of copper minerals with seawater were reported. It was found that froth formation in seawater at pH 9.5 was suitable to make the rougher circuit work properly, even without frothers. The Cenizas mining group successfully floated chalcocite, bornite and chalcopyrite in the Las Luces plant in Taltal in Chile using seawater (Moreno et al., 2011). Minera Centinela (Antofagasta Minerals S.A. Chile) is currently processing porphyry copper ores using a seawater mixture consisting of 20 percent fresh seawater and 80 percent recycled water. Lower consumption of flotation reagents was reported in both seawater and salt water. In addition, studies performed with synthetic seawater showed that certain frothers increase the froth volume, whereas others decrease it. Additionally, the froth produced with seawater carries a high amount of gangue, and low-quality concentrates are obtained, requiring more cleaning stages."

Jan 1, 2015

By Paul H. Johnson

A new system for leaching many types of ores has recently been developed on a commercial basis by J and J Research and Development, Inc. of Hanover, New Mexico. This revolutionary new leaching system consists principally of three new leaching reactors; viz, (1) a large, air-agitates, column-like reactor for leaching crushed ores that is constructed in an underground environment and has the inherent ability to do a very efficient job of leaching, (2) a vat-like, air-agitated vessel for leaching an rinsing finely ground ores and , (3) an air-agitated copper precipitation column that is built underground and utilizes an inexpensive dense or heavy scrap iron as a copper precipitant. Each of these new reactors have been used in a large leaching plant near Hanover, New Mexico.

Jan 1, 1973

By S. Frimpong, E. Siami-Irdemoosa, S. R. Dindarloo

"Electric and hydraulic shovels are the dominant loading machinery in surface mining operations. Despite their critical role in production and their high capital and operating costs, no reliable and comprehensive quantitative performance metric is available. In this paper, a stochastic shovel effectiveness (SSE) measure is proposed for the purpose of quantifying the performance effectiveness of these shovels. The SSE is based on the widely used method of overall equipment effectiveness (OEE) in the manufacturing industry. The OEE measures the performance effectiveness of equipment by multiplying its mechanical availability, utilization and production quality. In manufacturing processes, quality rate is the ratio of the total number of products minus the number of defective products – equivalent to the number of acceptable products – to the total number of products. The SSE similarly uses the mechanical-availability and utilization terms, but instead of quality rate it uses a new parameter named bucket rate.The variability or randomness of the input data, that is, availability, utilization and bucket rate, are further incorporated into the SSE, and a final stochastic SSE distribution is derived in the form of a probability density function. One hydraulic and one electric shovel in a surface mining operation were selected to test the validity of the proposed method. The SSE scores for the two shovels, operating continuously for one year, were derived and compared. As with the OEE, the three-parameter SSE method yielded more representative results for overall performance measurement than a single-parameter approach. Using Monte Carlo simulation, a three-parameter Weibull and a normal distribution were derived for quantifying the overall effectiveness of hydraulic and electric shovels, respectively. As a decision aid, the proposed methodology promises to render a more informative tool than traditional metrics for mine equipment maintenance and management."

Jan 1, 2015

By JIACHENG XIE, XUEWEN WANG, QINGBAO BAO, ZEWEN YAN

The general application of memory cutting technology to shearers is improving the intelligence of the working face, but it has its limitations. It is only suitable for conditions where the environment of coal seam is changing slowly. It compensates for the cutting height by changing the fuselage attitude, and frequently adjusts the height to control the learning cutting trajectory, but due to the problems of shearer control and height adjustment accuracy, it cannot adapt to and compensate for the change of cutting height in a timely manner, resulting in poor cutting accuracy. This study puts forward a virtual memory cutting method based on prediction of the shape of the armored face conveyor (AFC). The integrated key technologies include generation of virtual teaching cutting curve, height adjustment strategy of front and rear drums, cutting

By Ewan Wingate, Ranjit Prasad, Yanjun Liu

The phosphorus journey begins with the extraction of primary phosphorus in the form of phosphate in apatite through openpit mining and, in some rare cases, underground mining methods. The ores are processed in beneficiation plants to remove impurities before the phosphate rock concentrate is either sold on the open market or converted into phosphoric acid in downstream chemical production facilities by the wet acid process or thermal phosphorus routes. These can in turn be converted into fertilizers, as well as used in the food and electronic industries. The advent of the EV battery has given rise to a new use for purified phosphoric acid in the production of lithium ferro phosphorus (LFP) cathode material for EV battery cathode assemblies. The production of LFP relies on raw materials such as lithium carbonate, lithium hydroxides, iron salts and purified phosphoric acid.

Feb 1, 2024

By Erwin A. Morlan

Present methods of boring large hole mine openings are briefly reviewed. Factors that influence the design and choice of down-the-hole equipment for rotary drilling large holes are discussed. With formation drillability taken as a starting point, graphs and charts are given as an aid in the selection of bit load, circulation system, flow rate, drill stem, cutter design and rotary speed.

Jan 1, 1961

By R. D. Peterson

Autocad has become the standard graphics package for the mining industry as well as the general engineering profession. This paper discusses the evolution that mine planning has undergone and the trend toward compatibility with Autocad. It discusses the common use of Autocad in mine planning and systems modeling using a program called ICAMPS developed by Ohio Automation. As an example of its usefulness the use of the interactive ventilation network modeling capabilities are discussed specifically and are applied to mine planning at an operating trona mine. The ventilation analysis feature of the ICAMPS software works from Autocad drawing of the as-mined map and the projected mine layout. Using on-screen displays of these maps and the snap-on feature of Autocad, the planner designates nodes in the ventilation network, connects them into branches and selects branch characteristics from a side bar menu. The color coded ventilation network appears with the branch parameters alongside each branch. The software calculates the length of airways, computes the branch resistances where needed, converts the input into the required format and passes this information as input data along to the PENNVEN simulation program written by the Pennsylvania state University. Output is available in graphical as well as report format. The color coded graphs include pressures at the nodes and flow quantities on the branches. Since the networks come from the mine maps, the ventilation schematic displays are to scale and can be plotted separately or superimposed on the mine maps.

Jan 1, 1995