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By James P. Ludwig

While we are all aware of the need for reclamation of mine sites, few managers and engineers seem to be aware that good reclamation begins with the earliest plans for mining and processing of ores. Far too often the attitude that reclamation is an add-on to worry about at the end of the mining process dominates the thinking of mine engineers and management, A common result is that the reclamationist can be faced with mining and waste disposal designs that are nearly impossible to deal with effectively from an ecological perspective. Everyone of us has been victimized by the down time and maintainence cost that resulted from the purchase of an outwardly attractive, but poorly designed piece of equipment. When confronted by design defects in equipment, a distraught owner can always trade it in, call a consumer advocate, or follow up one of the "lemon laws" at either the federal or state level. A poorly designed mine for reclamation purposes usually cannot be treated either with ease or cost effectiveness. Good reclamation can be effectively prevented by the designs used when the mine was planned. The purpose of this paper is to share some of the experiences our firm has had with reclamation projects at mines in the Upper Midwest as these were influenced or controlled by mine design decisions. My aim is to sensitize mine planners and managers to planning processes they should consider, and hopefully use, early in the mining process to assure successful reclamation during and after mining. Many of the examples I will cite are from experience gained at the recently closed Jackson County Iron Company taconite operation at Black River Falls, Wisconsin. I am particularly grateful to Mr. Vern Metzger, mine manager at JCIC, for his unflagging support of good reclamation practices, employee training programs (which have included reclamation techniques), and his forebearance to put up with our group of ecologists. I realize that this was a time when there were significant internal and external pressures to cut all costs including reclamation efforts. The collaboration has been successful as you will soon see.

Jan 1, 1984

By E. D. Gardner, William O. Vandenburg

This chapter on the square-set system of mining em¬bodies the results of a special study of the subject made as a part of the US Bureau of Mines (USBM) general investigation of mining methods and costs. Data for the chapter were gathered by the authors during visits to mines using square-set mining, from information circu¬lars prepared by consulting engineers to the USBM on mining methods at individual mines, and from articles in the technical press and the Transactions of the American Institute of Mining and Metallurgical Engineers. Al¬though some of the properties discussed are no longer in operation, the methods described are still valid. The square-set system of mining has been very widely applied and is one of the oldest methods in use in the US. It is mainly employed for extracting rela¬tively high-grade ore in heavy ground. It is also useful in taking out pillars left in mining by other methods. It is used to some extent as an auxiliary method with many underground systems and as an alternate with cut-and¬fill, shrinkage, and open-stope methods when heavy ground is encountered. In some cases as much as 50% of the ore may be extracted by square setting at mines listed as using some other method of mining. A large tonnage has been mined yearly by square setting, prin¬cipally in the western states. Due to the high cost of timber and the relatively low average production per manshift, this system generally is not used when the ore can be mined by some other method; it usually is adopted as a last resort. Square setting, however, has a special field in that ore bodies not minable by other methods can be stoped by this system. As square-set mining was widely known, there was a tendency for years to use the method regardless of its suitability. With the increasing need for economy and the development of other methods, square setting has been superseded in many mines by cut-and-fill, top slic¬ing, or sublevel caving methods. The term square-set mining as used in this chapter includes all stoping methods in which the space made by the removal of the ore is timbered with framed sets. The sets usually are square in horizontal section. The stope may or may not be filled with waste rock as stoping progresses. HISTORY OF THE SQUARE-SET SYSTEM Prior to 1860, open-stope methods with stulls for casual support accounted for most of the mineral pro¬duction from underground mines. Attempts to mine large ore bodies that required artificial support resulted in disastrous cave-ins and loss of life. The art of mining received a tremendous impetus following the introduc¬tion of methods for mining the bonanza ore body which was discovered in 1860 in the Ophir mine on the Comstock lode, Virginia City, NV. This ore body was phe¬nomenally rich and eventually proved to be 122 m (400 ft) high, 27 m (90 ft) wide, and 98 m (320 ft) long. The mining of this large high-grade ore body taxed the best engineering talent of the time; the problem was finally solved by Philip Deidesheimer. According to Eliot Lord (1882): "At the 50-foot level the vein of black sulphurets was only 3 or 4 feet thick, and could be readily extracted through a drift along its line, propping up the walls and roof when necessary by simple uprights and cap-posts. As the ledge descended the sulphuret vein grew broader until, at the depth of 175 feet, it was 65 feet in width, and the miners were at a loss how to proceed, for the ore was so soft and crumbling that pillars could not be used to support the roof as in coal mines. They spliced timbers together to hold up the caving ground; but these jointed props were too weak and ill-supported to with¬stand the pressure upon them, and were constantly broken and thrown out of place. The dilemma was a curious one. Surrounded by riches, they were yet un¬able to carry them off and their mass of black sulphurets bade fair to become a white elephant on their hands. The Ophir Company began to wish themselves less for¬tunate, as their miners narrowly escaped burial day after day in their attempts to stope out the ore. "A young mining engineer, Philip Deidesheimer, was in charge of a quartz mine in Georgetown, El Dorado County, Calif., in the autumn of 1860, when this serious check to the development of the lode occurred. At the request of William F. Babcock, a trustee of the Ophir Company, Mr. Deidesheimer left his California mine and crossed the mountains with a letter from the direc¬tors of the Ophir Company, authorizing him to inspect the workings of their mines and make such changes in the method of timbering as should seem to him expe¬dient. After examining the vein he designed, in the course of a few weeks, a system of timbering which proved to be exactly adapted to the requirements of the work. Experiments which he had previously made in California gravel and quartz mines furnished the out¬line of his plan. This was to frame timbers together in rectangular sets, each set being composed of a square base, placed horizontally, formed of four timbers, sills, and crosspieces from 4 to 6 feet long, surmounted at the corners by four posts from 6 to 7 feet high, and capped by a framework similar to the base. The cap pieces forming the top of any set were at the same time the sills or base of the next set above. These sets could readily be extended to any required height and over any given area, forming a series of horizontal floors, built up from the bottom sets like the successive stories of a house. The spaces between the timbers were filled with waste rock or with wooden braces, forming a solid cube when¬ever the maximum degree of firmness was desired. By adjustments of these sets the ore bodies along the line of the lode were extracted with comparative ease and security." Most mining methods are evolved slowly and are the result of the combined efforts of a number of minds; Deidesheimer's feat was remarkable in that his system was immediately successful. He died in 1916 at the age

Jan 1, 1982

By Rudecindo S. Silo

[The principal characteristics of the process is that when applied in medium or in great degree it only needs unelaborated raw materials such as sodium chloride and calcium carbonate, or of medium elaboration, as sulphur which is found in large quantity in the North of Chili; however, the may be also applied to small copper plants provided that low cost sulphuric acid is available as a substitute for sulphur, that is, in. those plats of small capacity where large additional installations are not needed for the regeneration of the leaching solution. The method itself comprises 6 stages, namely: crushing, leaching, washing; of solutions, precipitation, regeneration of the leaching solution and fusion.]

Jan 1, 1965

By A. C. Kunkie, C. J. Marshall

Highly delaminated muscovite mica products (WG-1 and WG-2) have been developed by J.M. Huber Corp. The micas are characterized as a 325-mesh product having high brightness and very narrow particle size distribution. At 40% loading in polypropylene, WG-1 mica provides substantial improvement in tensile modulus and equal tensile strength to unfilled polymer; in high-density poly- ethylene (HDPE), WG-1 provides four times the tensile modulus and a 50% increase in tensile strength over unfilled polymer. Surface modification of the water-ground mica (SM ™) provides substantial improvement in tensile strength over untreated mica at greater than 20% loading in polypropylene; in HDPE, tensile strength is twice that of unfilled polymer.

Jan 1, 1988

By L. A. Roe

The year 1867 marks the first year of commercial production of phosphate rock in the United States. South Carolina produced almost all of the domestic output of mineral phosphate until phosphate mining began in Florida in 1888. During the period 1868 to 1949 the total marketed production of domestic phosphate rock was about 186 million long tons of which 71.5 percent was produced in Florida, 18 percent in Tennessee and 7 percent in South Carolina (1). From 1949 through 1960, Florida phosphate rock production has ranged Prom 71 to 77 percent of the total domestic production. Since three-fourths of the domestic phosphate production is from the Florida field, and since most of the phosphate from the Tennessee and Western fields is not processed, but used directly as electric furnace burden, this paper will concern itself almost entirely with water requirements for mining and processing ore from Florida. Figure 1 summarizes phosphate rock production for Florida vs. total United States production over the period 1947-1960.

Jan 1, 1962

By Keith G. Wallace

Coal mine ventilation systems are often subject to high leakage rates. As a result, changes in airflow resistance will strongly affect the efficiency with which air is delivered to the working place. One major source of airflow resistance is the line brattice used to direct air from the last open crosscut to the working face. Because it is a great distance from the fan, the resistance of the line brattice can result in more overall leakage than an equivalent resistance closer to the fan. Substituting auxiliary fans for brattice eliminates this source of resistance, with improvements in system efficiency and cost. Also, in some mines, the leakage that leads to spontaneous combustion can be reduced. The benefits obtained by several different brattice and fan substitutions have been studied by Mine Ventilation Services, Inc., under contract to the Bureau of Mines. Changes in main fan duty were compared with additional costs associated with auxiliary fans. Results indicate that in some circumstances, considerable leakage reductions and cost savings are possible.

Jan 1, 1986

By C. S. Davis

In being asked to present this paper on the improvements in loading and hauling equipment and the effect on unit costs, Mr. Van De Water, your program chairman, stated that his reason for coming to a contractor was due to the wide experience of, and I quote: "a large contracting firm using a variety of equipment on varying types of earth moving jobs." We people in Utah Construction Company are flattered that Mr. Van De Water singled out our Company for this assignment. Utah Construction Company's participation in open pit mine stripping antedates the 1920's, when overburden was being removed from copper ore in Bingham Canyon, Utah. Our first stripping con¬tract for the Copper Company was finished in 1912. Since that early beginning, Utah has, as a contractor, been engaged to strip and mine iron ore properties, coal properties, copper properties, uranium properties, phosphate,-gypsum, limestone and dolomite properties. And, as you know, the Company has become a major producer of iron ore from Company-owned open pit mines. Utah Construction Company has been instrumental in the evolution of open pit mining tools. Some of the first tools were the old wood and coal fired stream shovels which had to be fired hours before a shift started to insure a full head of steam, providing power to excavate with the then large 1-1/2 cubic yard buckets. Today, Utah's strip mining is done, with 18 cubic yard and 10 cubic yard crawler shovels. Yesterday's horse and mule drawn, iron wheeled wagons, with 1 and 2 cubic yard capacity, which were hand dumped by removing the false bottom, one 2 x 4 at a time, have been replaced by today's- 50-ton capacity, hydraulic, rear dump trucks and giant 40-ton coal haulers. Utah Construction Company used the early fresnes and wheeled scrapers which were horse and mule drawn. Often, an operator holding too tightly to a handle was thrown into his horses when a hard spot turned the scraper, a contrast with today's 20 and 25 cubic yard, self-powered diesel and diesel electric Gargantuan rigs; with power controls that relieve the operator of practically all physical work. This Company has pioneered many of today's advances in equipment with shop made prototypes, features of which were adopted and elaborated upon by equipment manufacturers.

Jan 1, 1959

By R. B. Inturi, R. G. Reddy

Solid-state reduction of roast Movat chromite ore with carbon was carried out as a function of the C/FeO ratio at temperatures ranging from 800°C to 900°C. The reduction was studied using thermogravimetric analysis (TGA). A two¬stage mechanism consisting of the reduction of FeO with carbon monoxide and the regeneration of CO by the oxida¬tion of carbon with CO2 was proposed. The rate-controlling step is the carbon oxidation reaction. A kinetic equation, that of random nucleation, was proposed. The activation energy for the reduction was determined to be 55,800 J/mole and is compared to those activation energies determined for other chromite ores.

Jan 1, 2000

By Saul J. Escalera

Mechanisms involved in the depression of the sulfides: pyrite, chalcopyrite, galena and sphalerite with potassium permanganate have been investigated. Flotation tests were conducted using potassium amyl xanthate, Z-6, and pine oil in the absence and presence of potassium permanganate at around pH = 6. 5 naturally yielded by the sulfides in the pulp. On the basis of crystal chemistry considerations, the amount of xanthate adsorbed by the sulfides depends on the amount of sulfur and metal ions present on the surface; thus, the avidity of the sulfides for xanthate should increase in the order: sphalerite C chalcopyrite 4 galena 4 pyrite, and the ease of depression response to the permanganate action should be in the same order. Depression of the sulfides in the system occurs primarily due to the removal of the collector ions by the permanganate ions to form manganese dioxide and dixanthogen according to the reaction: 3 M(RX)2 + 2 Mn04 + 4 H20 2 ? MnO2 + 3(RX-XR) + 3 M+2 8OH where M represents the metal ion, RX the xanthate ion and (RX-XR) the dixanthogen molecule. Results seem to indicate that the permanganate ions play a triple role in the system: (1) they convert xanthate ions into dixanthogen, (2) they further oxidize the mineral surface and (3) if present in excess, they may oxidize the xanthate beyond the dixanthogen stage with the formation of CO2, H20 and SO4. All sulfides, except for chalcopyrite, showed a depression response in the order predicted regardless of the order of addition of xanthate and permanganate reagents. Chalcopyrite did not depress as easily; this behavior may be due to the avidity of the colloidal MnO2 to adsorb Cu+2 ions on its surface, this would destabilize the colloid making it coalesce with the formation of a layer of precipitated MnO2 on the surface of the mineral. The presence of this layer would prevent further action of the permanganate ions on chalcopyrite.

Jan 1, 1970

By Sean Harvey

One of the manifestations of the dynamically induced failures in deep coal mines is the violent ejection of coal from the ribs. A possible protection against such failures is the use of a specifically designed dynamic support system with reinforcement units having the sufficient capacity to absorb the kinetic energy of the dynamic failure and a skin support that can adequately contain the disintegrated coal. With this method of mitigation in mind, a recently introduced yielding rock bolt, trade name Roofex, has been identified (Harvey and Ozbay, 2009) as a possible energy absorbing component of a dynamic support system. According to the manufacturer?s specification, the Roofex bolts can yield 300 mm (or more) displacement while holding 80 kN pull load. In order to assess the performance of this support unit in coal ribs, a series of in situ pull tests performed in two coal mines in Colorado. The results show that, under conventional pull test loading conditions, Roofex yielding bolts perform very close to their claimed specifications, thus showing a potential for their use as the main energy absorbing component of a dynamic support system. Further studies are required to confirm the in situ performance of these bolts under dynamic loading conditions and also to develop a containment component for a dynamic support system for the mitigation of dynamic coal rib failures.

Jan 1, 2009

By Xinzhi (Thomas) Du

"A longwall mining method is a productive mining method of coal extraction that involves the complete removal of large, rectangular panels of coal. Since this method causes deformations through the overlying strata to the ground surface, the surface- and ground-water regime above the longwall panels may be adversely affected and drained into the lower strata. The purpose of this study is to determine the effects of longwall mining subsidence on surface- and ground-water systems.This study is a site-specific hydrogeologic analysis conducted before, during, and after panel retreat at a site located over two selected longwall panels in the Pittsburgh coal seam in Greene County of Pennsylvania. Mine subsidence causes fractures in the overlying strata and enlarges bedding plane separations, increasing the effective porosity and storativity of the overlying strata. Generally, the water in deeper aquifers located in the lower fractured zone drains into the mine void due to the vertical fractures. Moreover, the water level does not recover after longwall mining (but may recover when the mine is flooded). The upper aquifers over the thick aquitard layers may maintain the water level or drop slightly during longwall mining and recover very quickly. The reason is that the underlying aquiclude layer has less change in porosity and permeability after longwall mining (Carver, 1994).A groundwater flow model-MODFLOW was used to predict the water table contours for the periods of pre- and post-mining conditions. The hydraulic gradients of post-subsidence became larger outside the panels and smaller inside the panels than that of the pre-subsidence. The groundwater hydraulic heads above the longwall panel dropped a maximum 50 ft in the study panels. The shallows monitoring wells that were less than 50 ft deep from the surface were deeply affected by longwall mining subsidence. For the intermediate wells that were more than 85 ft deep from the surface, where strata movement acted as a unit during longwall mining subsidence, there were little impacts of longwall mining on the intermediate wells in the study area. For the deep wells that were located below the Waynesburg sandstone, the water was drained to the underlying strata or even into the mine gob."

Jan 1, 2019

By Robin Dill, Wei Song, Andrew Perham, Leo Martin

"AECOM completed a subsurface exploration program for an 18-foot diameter, approximately 4-mile long rock tunnel project in Hartford, CT. The tunnel crosses the regional geologic trend through the middle of a sedimentary basin, passing through four separate rock formations, including two volcanic flows. Faulting is prevalent, with at least 15 faults encountered during the site investigation. Severe artesian flows were also experienced in several of the borings, requiring highly specialized drilling equipment. Sixty-two borings and associated testing were performed to characterize the structural geology, hydrogeology, rock properties and ground conditions. A phased program was carefully planned and implemented with participation of geotechnical and geologic specialists, with thoughtful evaluation along the way to react to the ground conditions encountered, and make appropriate refinements. This paper will discuss the subsurface program details; the integrated efforts used to effectively characterize the ground; and will summarize the final characterization presented in the GBR. PROJECT DESCRIPTION The South Tunnel Conveyance and Storage Tunnel project is part of the Metropolitan District (MDC’s) Long Term Control Plan to address discharges to various water bodies throughout the greater Hartford area. This program includes a main conveyance and storage tunnel; a tunnel boring machine (TBM) launch shaft and retrieval shaft; adit tunnels with associated drop shafts and connection structures; consolidation conduits and manholes; and a tunnel pump station (TPS) at the downstream end of the main conveyance tunnel. AECOM is serving as prime designer for the MDC on this project. The main conveyance tunnel (hereinafter referred to as the “South Tunnel”) will be a deep rock tunnel with an invert depth of approximately 180 feet at its downstream end and approximately 218 feet at the TBM retrieval shaft. The tunnel will have a finished diameter of 18 feet. The tunnel will rise in grade at a slope of 0.1 percent to its upstream end. Total invert depth along the deep tunnel alignment ranges from about 180 ft. to as high as 320 feet. The total length of the tunnel will be 21,754 feet. The South Tunnel will be constructed using a shielded TBM and fully lined with pre-cast concrete segments."

Jan 1, 2016

By Jon G. Baird

The suggestion of the use of measurements of trace amounts of mercury as a guide to the location of sulphide ore deposits was first made by the Russian, A. A. Saukov (1), in 1.946. Since Saukov's original work, many others have studied the abundance of mercury in nature, the association of mercury with sulphide ores and methods by which very minute quantities of mercury can be measured in air, soil, rocks, water and plants. The most abundant of the mercury bearing minerals is cinnabar (HgS). Native mercury is also found and sulpha-salts like tetrahedrite are known to have important mercury contents. Other sulphides of base metal deposits contain mercury in amounts ranging from parts per million to as much as one or two percent. (2) The mercury content of sulphide-free rocks is usually less than a few hundred parts per billion (1 ppb - 10-9), Soils usually contain less than 100 ppb and water less than 1 ppb of mercury. Normal atmospheric air contains about 1 nanogram (10-9 grams) of Hg per cubic metre although higher concentrations can be observed near mercury occurrences, sulphide deposits and volcanic exhalations.

Jan 1, 1973

By William R. Barton

The domestic portland cement industry consumes more than 12 million tons annually of raw materials chemically similar to fly ash. How these materials are used and how fly ash can serve in their place are discussed. Factors influencing whether or not a particular plant will use fly ash in place of an alternate material are discussed.

Jan 1, 1968

By P. T. Bissert, L. Yan, M. D. Klein

"Federal regulations require the installation of refuge alternatives (RAs) in underground coal mines. Mobile RAs have a limited ability to dissipate heat, and heat buildup can lead to a life-threatening condition as the RA internal air temperature and relative humidity increase. The National Institute for Occupational Safety and Health Office of Mine Safety and Health Research performed heat testing on a 10-person tent-type training RA and contracted ThermoAnalytics, Inc. to develop a validated thermal simulation model (TSM) of the tested RA. The TSM was used to examine the effects of the constant mine strata temperature assumption, initial mine air temperature (MAT), initial mine strata surface temperature (MSST), initial mine strata temperature at depth (MSTD), and mine strata thermal behavior on RA internal air temperature using 117 W of sensible heat input per simulated miner. For the studied RA, when the mine strata temperature was treated as a constant, the final predicted RA internal air temperature was 12.8°F lower than it was when the mine strata thermal behavior was included in the model. A 10°F increase in the initial MSST resulted in a 7.1°F increase in the final RA internal air temperature, whereas a 10°F increase in the initial MSTD yielded a 2.5°F increase in the final RA internal air temperature. INTRODUCTION Since 2008, the Mine Safety and Health Administration (MSHA) has required the installation of refuge alternatives (RAs) in underground coal mines (1). MSHA requires that RAs provide an environment with breathable air for entrapped miners for a 96-hour period. Heat buildup inside an occupied RA is a serious concern. Without a means to dissipate the heat and humidity generated by the occupants and the carbon dioxide scrubbing system, the temperature and humidity inside RAs could lead to severe discomfort or heat stress depending on the mine ambient temperature before and during occupation of the RA. NIOSH recommended an apparent temperature limit of 95°F in its 2007 report to Congress (2). In 30 CFR 7.504, MSHA has specified a maximum apparent temperature of 95°F inside an occupied RA (3). The apparent temperature is calculated using both air temperature and relative humidity (4). Calculations could be used to determine if the air within an occupied RA will reach the apparent temperature limit. In these calculations, in order to simplify the problem, the mine temperature could be assumed to remain constant. With this assumption, the effects of the mine strata thermal mass and thermal conductivity on the heat buildup in an RA are ignored. OMSHR research has shown that the mine air and strata temperatures surrounding an RA increase when subjected to the heat of an occupied RA (5). Thus, calculations performed with the assumption that the mine temperature is constant would under-predict the resulting dry-bulb temperature and apparent temperature for a given RA occupancy. The mine air temperature has been used as the basis for RA temperature calculations. However, research has not been used to confirm that the mine air temperature is the appropriate basis."

Jan 1, 2016

By E. E. Jones

The lignites of Arkansas, Louisiana and Texas are typically described as muitiseam deposits which contain quantities of day and sand in thin lenses or in admixture with the fuel itself. These materials are often included in the run-of-mine fuel and can have very adverse effects in the end use. Since May of 1982 the Dow Chemical Co. has operated a pilot plant for the beneficiation of lignites. This facility has successfully removed sand, clays and petrified wood from the lignite producing a fuel comparable to or better than the selectively harvested run-of-mine materials. The design, operation and results from this plant were presented by J. H. Everitt at the 1984 Coal Technology Conference.

Jan 1, 1986

By Harry E. LeGrand

The purpose of this paper is to outline briefly some basic principles of ground-water hydrology that have application in mine hydrology and to suggest that an understanding of these principles can help to forestall problems that are internal as regards mining operations and external as regards damage or harm to surrounding areas. The development of a mine below the water table pleads for accurate values to answers of hydrologic problems. Such internal problems involve both an inflow of water without adequate drainage facilities and a deficiency of water for the required mining or milling use. Methods which give acceptable quantitative values for the solution of many ground-water problems depend on rather simple geologic structures, characterized chiefly by homogeneous rocks of considerable areal extent. Unfortunately, mining operations are likely to be centered where rocks are not homogeneous. Consequently, methods that attempt to show values of the storage and transmitting capacity of rocks in mining areas must be applied with caution. In spite of complex geology and apparent uniqueness of individual mines and quarries, adherence to some concepts of ground-water occurrence and movement should be helpful to mine operators. Mining operations that extend below the water table disturb the natural hydrologic regimen. Prior to development, the water table slopes away from the site of a mine in at least one direction, but as soon as development begins and water is removed from the mine, the mine becomes the apex of a depressed cone in the water table, causing a convergence in the flow of water toward the mine, The behavior of the cone of depression, as it tends to deepen and to increase in areal extent when the mine is deepened, is related to the rate of withdrawal of water necessary to keep the mine dry. The significance and nature of the cone of depression in the vicinity of pumped wells has been studied by ground-water hydrologists for years, but the cone caused by pumping water from mines has generally been less systematically appraised. The geologic and hydrologic settings of mines range greatly so that a simple standard procedure for dealing with problems

Jan 1, 1972

By T. Shumka, M. J. Druckenmiller

"INTRODUCTION As we push further into the 21st century and closer to a more efficient mine, safety and operational enhancements are the two major keys towards attaining success. The Crusher Vision Automation System (CVAS) is a technological advance that will allow an operator to achieve higher safety and higher operational goals in the same piece of equipment. The CVAS is a patent pending system and method for measuring and maintaining the closed side setting (CSS) on gyratory crushers. In the same equipment and technology package, the CVAS will also allow safer placement of main shaft pieces for maintenance and replacement. This technology yields multiple uses and allows a site to significantly enhance safety and operational efficiencies. This measurement technique is used to provide more accurate data and faster data collection times than current techniques used today. It will give crusher operators accurate and reliable measurement for the CSS in a live, operating environment. Measurement data can be collected in five minutes allowing for fast adjustment of the mantle position and subsequent enhancement and streamlining of a crusher and downstream flowsheet. The advantage of this system is that it is permanently mounted at the crusher location, where the operator can turn the system on and off as many times as they like throughout the day with a goal of maintaining a constant CSS gap based on production and maintenance criteria to help streamline operations and enhance safety efficiencies.Regarding its other main functional area, mainshaft maintenance, it allows this work to be performed remotely while keeping personnel safer and out of harm’s way. SAFETY ENHANCEMENT The safety factor enhancement with this system is extreme. It does not require the use of overhead cranes, cleaning out the crusher, lowering people into the crusher or having the operator lower paint cans or lead balls into the crusher pocket while the crusher is in operation for measuring the setting. In order to perform the CSS measurements, the operator only needs to operate the laser through manipulation of a joystick while watching the video feed. Danger of a person falling into the crusher while trying to take measures is eliminated, as are the effects of handling lead balls and tracer dyes."

Jan 1, 2015

By F. Mielli

Over the last three years there has been an increase in mining congress and conferences focusing on water management. Water in mining is a key concern for mine managers and operations, and we are now seeing this operational dilemma escalated to the level it deserves. According to Frost & Sullivan research, mining water and wastewater treatment and its related technologies will be a U$3.6 Billion global market in 2016, which translates the importance of this issue. Looking at the current mining trends, some factors increased the importance of water in mining operations, including: ? Future mining investments will be located in geographical locations where water is scarce (water stressed areas) ? A decline in grade will increase the intensity of mineral processes and therefore increase the use of the water ? Increased sustainability and regulations will extend the control/monitoring of water during the entire mine life cycle representation of the mine water flow system. A water balance has several benefits/objectives in a mine operation: ? Mine planning/simulation of mining scenarios/climate change Production optimization ? Minimizing strategic and operational risks ? Social license to operate ? Water-smart mine planning ? Target: water neutral mines ? Benchmarking within and between sites ? Sharing knowledge/technology transfer ? Reporting/communications ? Permitting/Compliance

Feb 23, 2014

By George Innes

The soda ash business in the United States has undergone a sweeping technological change in ihe last 20 years. In a world where synthetics are continuzlly replacing natural products, here we have exactly the opposite, a syntheric chemical being replaced by a natural product. This change is nearly complete in the U.S. and is beginning to take place in Europe and other parts of the world.

Jan 1, 1980