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By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

5.1 TECHNOLOGY FOR INJECTING GROUT INTO BOREHOLES The grouting of fractured rock aquifers is carried out in separate stopes' whose size is determined by the hydro¬stratigraphy and the hydrogeologic properties of the rocks. The number of grouting stopes required depends on the number of intervals in the hydrogeological section. Each grouting stope can include one or several aquifers. Com¬bining several water-producing strata into one stope is pos¬sible only when the values of their permeability coefficients are very similar. In order to achieve efficiency, as many aquifers as possible are included in each stope. In practice, the length of a grouting stope in a borehole usually ranges within 10 to 40 m, but occasionally up to 100 m or more. When conducting grouting operations through boreholes drilled from the face of underground workings, the stope's size can be determined by the thick¬ness of each fractured zone (fault) or by the length of the hole if the entire rock is fractured. Injecting grout into separate intervals of fractured rock can be done from the bottom to the top with ascending stopes or from the top to the bottom with descending stopes. Injection from bottom to top is always preferred. Injection also can be accomplished in separate fractured permeable horizons in the section. The STG integrated grouting method is based on the use of packer and injection equipment and technological schemes that facilitate injection in highly isolated fractured aquifers. For this purpose STG has developed a standard series of packers. 5.1.1 INJECTING GROUT THROUGH BOREHOLES DRILLED FROM THE SURFACE Grout can be injected according to one of four techno¬logical schemes depending on the depth of the fractured aquifers, their hydrogeologic properties and the availability of grout injection equipment if the area is remote (Fig. 43). In the first and most preferred technological scheme (1), the grout is injected from the bottom up with ascending stopes. When this scheme is employed, grouting holes are drilled to the entire projected depth based on the field investigations injection tubes is installed above the top of the first hydrostratigraphic unit to be grouted. This scheme al¬lows the grout to be injected only into the permeable stra¬tum or strata isolated by the packer near the bottom of the hole; it precludes the need to clean or redrill the hole before injecting grout into the next overlying stope. This ascending stope scheme is preferred because of its simplicity and ef¬ficiency. It is used in most of the grouting of saturated fractured rock for the purpose of isolating aquifers while excavating deep mine shafts in the USSR. The second technological scheme (II in Fig. 43) injects the grout in sequence from top to bottom with descending stopes. Injection under this scheme is accomplished through the hermetically-sealed mouth of the hole. It is most advis¬able to grout with descending stopes in saturated fractured rock wherein the aquifers constitute thick networks of frac¬tures. Under these conditions it is practically impossible to drill a grout hole to the entire depth of the underground workings due to the large production rate of ground water. In conducting isolation operations with descending stopes, additional work (relative to ascending stopes) is necessary to drill out the grout in order to create and inject the next stope. As a result, the total amount of drilling required to drill out grout can even exceed the volume of drilling of original rock. Consequently it is advisable to use this inefficient scheme only for injecting grout into holes that contain prolific frac¬tured aquifers at depths less than 150 to 200 m. The third and fourth technological schemes (III and IV in Fig. 43) are used in the selective grouting of separate aquifers. For example, these methods would be applied when a grout hole is drilled to its entire depth, wherein grouting of the upper aquifers must be done first so that the sinking of the first shaft can begin prior to deeper grouting. The third technological scheme is used for the selective injection of grout into an aquifer with a thickness of up to 5 m. For this work the DAU-1-2 removable dual packer is installed. It is lowered into the borehole on an injection pipeline. For aquifers with thicknesses of more then 5 m, the selective injection of the grout is carried out according to the fourth technological scheme; a combination of the DAU-2 hydrodynamic plug and the DAU-1 packing device is used. In order to implement this injection scheme, the DAU-2 hydro-dynamic plug is installed at the bottom of the fractured aquifer and the DAU-1 packer is installed at the top of the aquifer.

Jan 1, 1993

By R. Barthel, O. Nitzsche, J. Pateiro Fernández, T. Cramer

The Hong Gai coal field in northeast Vietnam has been the main coal mining area of Vietnam for more than 150 years. Anthracite coal is produced from several open pit and underground mines situated close to the UNESCO world natural heritage site Ha Long Bay. The mining-induced environmental impacts such as dust emissions, acid mine drainage, and visual impairments due to waste dumps resulted in severe conflicts of interests regarding future land use and the protection of the world natural heritage site Ha Long Bay. Within the RAME project (Research Association Mining and Environment in Vietnam), Brenk Systemplanung is contributing to an improved environmental and sustainable planning in Vietnam's mining industry and the reduction of environmental impacts on Ha Long Bay by developing suitable and sustainable technology and planning measures (e.g. for dump construction/rehabilitation, predictive modelling, and/or monitoring) for Vietnam's leading coal producer.

Jan 1, 2011

By A. Adu-Acheampong

Photogrammetry and laser scanning has been employed at a number of Newmont mine sites to mitigate risks associated with conventional structural mapping, determining the geometry of voids from old underground workings, and generating topography in areas of slope instability. Laser scanning has also been used to evaluate as-built pit slope configurations with respect to design assumptions, operational practices, and rock fall potential. Recently, remote sensing applications carried on an unmanned aerial vehicle (UAV) were used to generate base topography at some Newmont sites. UAV are generally more convenient and less expensive and can be utilized in areas where cloud cover prevents manned aerial photography missions. This paper discusses these applications, and provides commentary on their benefits and limitations based on recent experience.

Feb 27, 2013

By Jock McGregor, Deepak Malhotra, Leonard Harris

After more than 100 years, alkaline cyanide leaching of gold and silver ores, either directly in the case of oxidized ores, or after pretreatment of refractory ores by roasting, pres­sure leaching or bacterial leaching, remains the dominant r leaching method to extract the precious metals f om ores. Leaching with halides (chlorine, bromine and iodine) and with thiourea and thiosulfates is less common but prac­ticed in some cases to dissolve the precious metals both from ores and jewelry and electronic scrap. Cyanide solutions can contain from 1 ppm Au to 30,000 ppm Au. According to the source, i.e., agitated tank leach­ing, heap leaching, eluates from stripping activated carbon or waste electroplating solutions. Similar variations occur with silver which can have a profound influence on the recovery method. The presence of other elements in the leach solu­tions, particularly mercury and copper, likewise play an important role in the procedures required to recover the gold r and silver values f om solution. The same circumstances are found when lixivants other than cyanide are used to dissolve the precious metals. For decades, the preferred method of recovering gold and silver values from alkaline cyanide leach solutions was by zinc dust precipitation according to the Merrill Crowe process developed in the late 19th century. Finely ground gold and silver ores or concentrates were either leached directly or after roasting, in agitated tanks or Pachucas and subjected to solid/liquid separation by filtering or by treat­ment in counter-current-decantation washing thickeners (CCD). This solid/liquid separation step was often very dif­ficult especially when ores containing high quantities of clay were treated which caused filtration or thickening problems. Following testing and development by the U.S. Bureau of Mines (USBM) in the late 60s, the introduction of carbon­in-leach (CIL) or carbon-in-pulp (CIP) plants to recover gold and silver from leach pulps was one of the greatest opera­tional and cost saving improvements made in the industry in South Dakota and quickly spread around the world to be the most common process to recover gold and silver from cyanide solutions.

Jan 1, 2000

By E. P. Gustafson

Demand by precious metals explorationists for cost effective means to target subsurface geologic structures worthy of evaluation by means of drilling has led to the use of the predictor-correlator technique. To locate polarizable targets, the predictor-a localized inhomogeneity in electrical properties-is placed at various locations in the computer-simulated subsurface region, and correlated with the potential distribution observed in the field. The correlation coefficient obtained is assigned to the subsurface location. IP targets are extracted by calculating a second correlation section based on higher-frequency illumination and subtracting it from the first. The locations of correlation difference correspond to the locations of polarizable mineralization.

Jan 1, 1989

By P. Tsakiris

The increasing social interest for the environmental issues, forces the authorities to enact more rigorous regulations. The mining industry is one of the sectors that concentrate vigorous remonstrance. It is an absolutely justified reaction, as a result of the numerous contaminated and polluted sites that have been inherited by previous operations and they remain unremedied. The lack of a consolidated global legislation, transfers the burden of decisions to the national level. This paper consists of two parts. At the first part, it discusses the critical role of the state to form an effective environmental policy, feasible for the context of the national economy. Afterwards it analyses two of the main points, which must be considered by the regulator for the excavation activity, the abandoned sites and the duration of the mining investment. The aims are to defuse, in the short-term, the public pressure, protecting the economic growth and, at the same time, to form a basic structure for the development of the corporate social responsibility. The second part presents an alternative financial instrument for the Greek regulatory framework, conformed to the characteristics of the Greek Economy, and analyses the expected benefits both for the business and the social welfare.

Jan 1, 2002

By M. C. Fuerstenau

The zero-points-of-charge of apatite, calcite, and fluorite are pH 6.4, 10.8, and 10.0, respectively. Scheelite is negatively charged above at least pH 3. Flotation responses of these minerals in the presence of potassium oleate and sodium silicate are presented and compared with electrokinetic data. Colloidal silica appears to be the species principally responsible for calcite depression, while silicate anion is the species responsible for fluorite depression. Additions as high as 1 x 10-3 mole/liter silicate have no effect on the flotation responses of apatite and scheelite. Selective flotation of nonmetallic minerals is difficult to achieve with fatty acids or soaps by themselves. As a result, specific reagents are added to aid these separations, and one of the reagents commonly employed for this purpose is sodium silicate. Flotation separations of various calcium¬ bearing minerals such as fluorite from calcite (1,2,3) and scheelite from calcite(24) and apatite(2,5) almost always involve the use of sodium silicate, for example. The mechanisms by which sodium silicate functions as a depressant are still not understood; this fact is probably due to a number of reasons. That is, the dissolution process of sodium silicate is complex, giving rise to a number of ionic and colloidal species. (6) In addition, the type and concentration of these species depend on the ratio of Na20 to Si02, the concentration of sodium silicate, and the pH of the system. (6) At the present time, it is not known which species, colloidal silica or silicate anion, is responsible for depression. If colloidal silica is the species that is adsorbing, then adsorption must occur by electrostatic attraction between the colloid and the mineral surface. Silicate anion, on the other hand, may adsorb either physically or chemically. The objective of this paper is to determine first the active species of sodium silicate and then the conditions under which this species will adsorb and function as a depressant.

Jan 1, 1968

"With a longstanding reputation for engineering expertise, Weir Minerals continually develops solutions and technology to better serve the mining industry. Recognizing that throatbush wear rate has a major impact on the overall efficiency of slurry pumps, Weir Minerals has developed superior rotating and axial adjustment technology.In many applications, the pump’s throatbush is the component that has the shortest life compared to the impeller and liners, with considerable variability.Adjusting the gap between the throatbush and the impeller front shroud reduces hydraulic recirculation in the pump. This prevents localized wear on the throatbush, improves hydraulic efficiency and lowers the total ownership cost for the operator. To avoid impacting the plant’s production, these adjustments are often performed while the pump is operating. However, this can have safety implications for individuals working at the front of the pump unit.“Manually adjusting an alloy throatbush on a large pump requires several people and is laborintensive. It requires mechanical tools to adjust the four pusher bolts, one at a time, in order to reduce the gap between the throatbush and impeller. We wanted to find a safer and quicker way to extend the wear life of the pump with regular adjustments, which led us to development of this technology,” said Marcus Lane, global product manager for centrifugal pumps for Weir Minerals.“Our automated throatbush adjustment solutions are available for pumps fitted with either rubber or alloy throatbushes on Warman slurry pumps used in the most arduous applications, and have been designed with our customers’ safety and pump operation in mind. By mechanizing the adjustment procedure, personnel are removed from the line of fire, and the accuracy of axial movement is increased,” said Ron Bourgeois, director of slurry pumping technology group for Weir Minerals."

Mar 1, 2019

By Dennis J. Lachel, Lloyd B. Underwood

In recent years a great number of papers have been presented at symposiums and have appeared in the literature relative to geologic prediction for rapid excavation and tunneling. Many of these papers describe research projects now underway to investigate tunnel site selection by remote sensing techniques, seismic holography, electro¬magnetic pulse sounding, optical scanning for structural features, and many other exotic geophysical techniques. While it is possible that this research will produce techniques that may prove to be very useful, it appears for the present at least, and perhaps for another decade, that there still will be no substitute for conventional exploration methods such as coring boring, geologic mapping, studies of existing wells, and proven geophysical techniques. Nevertheless, there is still room for tremendous improvement in the conventional techniques for geologic prediction in tunneling. These include: more rapid and accurately aligned coring borings drilled parallel to the tunnel alignment; improved geophysical surveys both prior and during construction; improved methods for predicting ground¬water inflows and water pressures, both of which can greatly influence the cost of driving tunnels. Geophysical techniques can also be ap¬plied to locate deeply incised glacial troughs or ancient buried stream channels that might cross the tunnel alignment. In the meantime, while some researchers continue their efforts to¬ward a breakthrough in new techniques for geologic prediction, it is recommended that other researchers direct their efforts toward sol¬ving specific problems such as accurately predicting ground-water conditions, determining locations of high geostatic stresses, and locations of major fault and shear zones.

Jan 1, 1997

By K. Vaxevanidou

A combined chemical and biological treatment for the removal of heavy metals and arsenic from a contaminated soil was studied as a potential method for soil remediation. Small scale and column tests were conducted in order to ex-amine the effect of plant-compost and Na2CaEDTA addition on a calcareous soil highly contaminated with heavy metals and arsenic. EDTA is known to be an efficient leaching agent of heavy metals from contaminated soils but has no effect on arsenic. Compost tea on the other hand contains humics that can leach several iron compounds including Fe(III)-oxides and thus can extract arsenic bound to these oxides. The action of Fe(III)-respiring bacteria D.palmitatis was also evaluated for the reduction of iron oxides and compared to simple chemical treatment in the presence of compost in small scale tests. Results indicated that the addition of compost and EDTA into soil pulp lead to the predominance of reductive conditions and the simultaneous dissolution of both heavy metals and arsenic at high percentages. The presence of D.palmitatis did not further enhance the reductive dissolution of Fe(III)-oxides by compost and EDTA as it was observed in the inoculated samples. Column tests using soil as received revealed that, although the extraction of metals seems to be a slow process, compost is an effective oxygen barrier that promotes the reductive dissolution of iron oxides and the subsequent arsenic release together with the dissolution of heavy metals by EDTA.

Jan 1, 2005

By R. A. Pond

Two 6.17 m (20 ft 3 in.) diameter raises, concrete-lined to 5.49 m (18 ft) inside diameter, were completed in 1978 at the Monterey Coal Company Number One Mine near Carlinville, Illinois, by Frontier-Kemper Constructors. These two raises are the largest in cross-section yet completed by full-face upreaming, and the success of this project is expected to increase the application of raise-boring to coal mine shaft construction. WHY 6.17 M (20 FT) DIAMETER ? Raise boring is well accepted in the metal mining industry for a variety of applications, and is gaining in acceptance in the civil works construction industry. The use of raise boring to construct vertical openings for coal mines has not been as widely accepted, even though coal mining requires, per mine, the greatest number of openings to the surface of any underground activity. Several factors have influenced the low utilization of raise boring in coal mining: 1. Coal mine shafts must often be of large diameter to pass the required high volumes of ventilation air at acceptably low water gage pressures. Cross-sectional areas of finished shafts exceeding 23.23 sq m (250 sq ft) are common. 2. The life of ventilation shafts is comparatively long, and the typical sedimentary strata overlying coal seams normally require that the shafts be lined. Shafts on the intake ventilation circuit must have permanent water-tight linings. 3. Unconsolidated overburden at the surface is often thick, and as reaming cannot be safely utilized in unconsolidated material,

Jan 1, 1979

By Marion A. Goudie

The Devonian salt basin, which contains the Saskatchewan Potash deposits, extends from just east of the foothills in Alberta, north as far as the Peace River area, across Saskatchewan and into Manitoba as far east as Range 10 west of the First Meridian and south into Montana and North Dakota. The basin is closed everywhere except to the northwest. The known potash deposits are confined almost entirely to the Province of Saskatchewan, with the exception of a small area in western Manitoba bordering the Saskatchewan boundary. The following discussion will concern only the Saskatchewan part of the basin. The evaporite series in the basin is defined as the Prairie Evaporite Formation of the Elk Point Group, of Middle Devonian age. Recent work done by potassium-argon dating methods has indicated an Upper Middle Devonian (Givetian) age of from 265 to 347 million years for the potash. The Elk Point Group consists in ascending order of the Ashern, Winnipegosis and Prairie Evaporite Formations. The Ashern formation, sometimes called the Third Red Bed, consists of dolomitic shales or shaly dolomites. The Winnipegosis is a reef type dolomite, usually with good porosity, and in many cases oil-staining, although to date no production has been obtained. The Prairie Evaporite formation consists of anhydrite overlain by halite and finally, in Saskatchewan, by the potash beds. In almost all wells which have been cored for potash the lowest potash bed is underlain by one or two bands of anhydrtte, which are used as marker horizons. Cores from a few wells which cored to the bottom of the salt series have shown flecks of potash throughout the halite.

Jan 1, 1959

By Jed H. (Original by) Mosgrove

Good mine ventilation starts at the drawing board. A coal mine will either be adequately ventilated or not, depending upon how good a job was done in the planning. Poor planning will not only result in inadequate ventilation, but may also lead to low productivity. A mine foreman cannot achieve high productivity while trying to maintain 4.2 ma/s (9000 cfm) of air at his last open crosscut.

Jan 1, 1981

By S. Chander

A comparison of gold, platinum and sulfide ion selective electrodes was made for determination of Eh in solutions containing hydrosulfide ions as a model system. The comparison was made in terms of the accuracy of the measured response, response time, pH dependence, and reproducibility of measurement. The sensitivity of each electrode towards changes in hydrosulfide ion concentration was measured in terms of the change in measured Eh per decade change in concentration. On the basis of a detailed investigation of the electrode processes occurring at the surface of gold and platinum electrodes, it was postulated that within the pH range investigated these electrodes respond to changes in the hydrosulfide ion concentration in solution. In comparison, the sulfide ion selective electrode is known to respond to changes in the sulfide ion activity in solution. Although the potentials measured with gold and platinum electrodes were mixed potentials, pretreatment procedures can be used to obtain a signal suitable for process control. For control of hydrosulfide ions in flotation pulps, the use of a gold electrode pretreated at 1.0 V with respect to a standard hydrogen electrode is recommended.

Jan 1, 1992

By W. –E. Marx, M. Faber, R. Pollak, I. Astberg

INTRODUCTION Essentially three strategies are pursued in parallel for protecting the underground working force in mining against the consequences of methane ignitions which might lead to explosions: • Sufficient ventilation for avoiding the formation of explosive methane-air mixtures. • Avoiding sources of ignition caused possibly by electrical equipment or friction. • Structural explosion protection for limiting explosion propagation to the farthest-going extent for the case that methane is fired because of failing of the above preventive measures taken. The corresponding methods taken in mechanized roadheadings with point-attack roadheaders in German coalmining are subject of this paper. VENTILATION In ventilation of roadheading sites the following is to be considered in respect of methane control: • Sufficient air flows by volume being cycled to the heading face for diluting released methane to safe concentrations. • Sufficient local air velocities for effective mixing of methane and air in the whole heading site, in particular directly on the heading face and underneath the roof. Furthermore, ventilation needs to be laid out in a way that cut- ting does not result in health affecting dust exposure at any working place. Accordingly, the ventilation systems shown on Fig. 1 including primary and, if necessary, secondary auxiliary ventilation air ducts as well as dedusters, are used in roadheadings. This equipment is run according to the following principles: • If the roadheader is at standstill, the heading face is ventilated by the free air jet from the blowing duct closest to the face. In this operation phase the deduster is shut-down. • During cutting, the exhaust of the blowing air duct is automatically closed, and the deduster is taken into operation. The in- coming fresh air is now locally discharged via a lateral orifice, or distributed by Coanda-type ducts from the primary or secondary ventilation air duct. In this way, a stable dust wall not disturbed by the jet of the air duct is formed in front of the heading face. Only the ventilation air stream taken in by suction of the close-to-face deduster is passed through the inby zone of the heading face (over approx. 20 m). The clean exhaust of the deduster is dischayed to the roadway in some distance outby. Immediately at the heading face, methane accumulations possibly released by cutting are diluted by compressed-air jets from air-movers located near the roof which assure more rapid motion of the air without distuhing the dust wall. • In the zone of overlapping of primary and secondary duct and the deduster - that zone possibly is poorly ventilated during cutting - sufficient local air speed is assured by Coanda-type ducts or additional ventilation jets for avoiding methane accumulation. The regulations of the inspectorate specifies geometrical conditions to be met with these configurations of ventilation equipment. In-seam roadways are ventilated at rates > 0,5 m/s. For dedusters, present-day ventilation air flows are of 600-800 m+/ min. Ventilation monitoring and control is assured by units for measuring methane and ventilation air flows. If pre-set thresholds are exceeded or fallen short of, these measuring units shut-down - dependent on potential hazard - any not intrinsically safe electrical equipment in the roadheading, either totally or in limited zones. In addition, CO-measuring units near the roadway en- trance serve for early detection of mine fires. In spite of this ventilation layout and the equipment used and in spite of the water spray systems on the cutting head (discussed later in this paper) several cases of methane ignition and subsequent burning off (however, no explosions) have been recorded in the recent past. Therefore, the above-described ventilation is nowadays complemented in many cases by machine-mounted ventilation equipment for the immediate surroundings of the cutting head. Ventilation of the surroundings of the cutting head Investigations carried out subsequent to the above-mentioned gas ignitions have shown that the high ventilation air speed necessary for rapid dilution of methane could not permanently be arrived at in the following zones: • The direct zone of cutting, in particular during sumping. • The floor zone above the debris, predominantly below the cut- ting head. Accordingly, VOEST ALPINE-Bergtechnik, a producer of mining machinery, in cooperation with DMT developed for point- alttack roadheaders a novel machine-mounted ventilation equipment, the Jet-Block" (AERO SAFE Jet-Block) shown on Fig. 2. This system allows to ventilate the above-mentioned critical zones with high flow speeds. One AS Jet-Block is mounted on each side of the boom approx. 0.5 m behind the cutting head. The blocks discharge compressed-air jets with high energy from 10 nozzles per block into the hazardous zones (Fig. 3). Two nozzles of each jet block are tangentially oriented toward the upper circumference of the cutting head, the others are arranged fan-like with orientation to the heading face underneath the cutting head and the debris. The nozzle array of the blocks as well as the com-

Jan 1, 1997

By J. R. Carr

A crucial concern when implementing computer algorithms for geostatistical analyses on microcomputers is speed of execution. Kriging, in particular, typically relies on a Gauss elimination algorithm to solve for weights. Because such an algorithm is required for each estimate, the solution for weights can result in very slow program execution speed on a microcomputer. One approach to enhancing the efficiency of Gauss elimination is demonstrated herein. The upper triangle plus diagonal of the intersample covariance matrix is used in a modified banded Gauss elimination algorithm. Results show that such an algorithm yields approximately a two-fold reduction in execution time for kriging when the number of nearest neighbors used for estimation is large.

Jan 1, 1990

By R. Owen

The vision-based approach to process control involving fine particles in harsh on-line environments is discussed in this paper. The sensor equipment at the process location, consisting of a light source and a CCD camera provides RS-170 B&W video output. The video can be seen on a process monitor in the control room and is sent to a computer based Vision Processor. The Vision Processor contains a video digitizer and Canty developed software that extracts process information. The iron mine application controls thickener agent feed rate and thus settling pond overflow clarity. The sensor is mounted in the overflow flume of the outdoor settling pond and is used year around in the Minnesota weather. Alternate control system needs a low flow water sample which is subject to freezing in winter. The computer based vision processor provides 4-20 mA analog outputs for real time control as well as file archive for a history record.

Jan 1, 2001

By Jun Han

Coal has been mined in the Kailuan mining area for more than 130 years. The remaining reserves consist of, in large part, coals that would have been considered economically unminable or technically not feasible by the previous generations. Some of the current operations have to resort to overmining because the lower seams had been extracted in the past. This paper deals with the feasibility and proper layout of mining roadways of overmining carried out in the No. 5 seam of Qianjiaying coal mine of Kailuan mining area using numerical and physical simulation. FLAC2D was used to investigate the characteristics of stress and displacement in the overburden after extraction of the lower seams. It also analyzed the proper layouts of gateroads in the upper seams, i.e. locating them in the stress-relief zone of the gob so that their stability can be easily maintained. In addition, a two-dimensional physical model was constructed for investigation of damages to the upper seams due to mining of the lower seams. Finally, based on the results of investigations, proper gateroads layout was designed and successful extraction was implemented for panel 1357 in the No.5 seam.

Jan 1, 2009

By Randy Ynchausti

ERIC GUTIERREZ, Knowledgescape: Our next speaker is Randy Ynchausti. He's the director of development, Knowledgescape systems division, of EIMCO Process Equip- ment Company. The title of Randy's talk is "An Expert Control System for Phosphate Beneficiation." RANDY YNCHAUSTI: System integration. How does the systems integrator survive when caught between plant engineers, plant management, and third-party engineering firms, and stay within the budget of the corporate goals? I'm not sure that anyone knows how to do all of that on one project. Results are critical when we talk about how systems integrators work with operating people, how the operating people want systems integrators to work with them, and how both groups work together so that at the end of a project, you have been provided with solutions that meet your needs and solve your problems at a fair price. How does the integrator's role change when working with different types of professionals, such as plant managers, plant engineers, engineering firms, or other system integrators? Finally, what is the dynamics of people working with machines and providing services and solving needs? The average number of employees per pound of copper processed has decreased significantly during the past 15 years. I would dare to generalize and say that the average number of employees per whatever unit of measure we have in whatever industry we work in has decreased over the last 15 years. From a system integrator's perspective, there are some clients who lack a bit of internal expertise as corporate downsizing occurs, and that's one reason why we go out to system integrators or third-party vendors and buy things from them to solve our problems. Downsizing really amounts to savings, but more than that, I think Brian expressed this and I agree with him, it also amounts to a cost. Unfortunately, most of us count the savings and none of us count the cost in that approach. It's easy to count the savings, which is one reason why we count it so quickly. Maybe that also accounts for why we set our pencils down so quickly after we get that dollar value. Maybe we should pick that pencil up every once in awhile and refigure the expense, the cost to us, and determine what we're going to pay during the next year or two or three in losing that expense, or that staff. A broad experience base accumulated over projects at various plants helps system integrators to provide services to clients. This experience enables the system integrator to

Jan 1, 1998

By W. M. Jr. Aubrey, R. L. Stone

INTRODUCTION Most metallic minerals and some industrial minerals have a relatively high specific gravity and most have at one time or another been concentrated by gravity methods. The principles of gravity concentration are straightforward, well documented and easy to understand, but in practice there are many pitfalls that await the engineer in the development of an integrated flowsheet. Gravity concentration equipment has a long history of use and there is a great diversity available. The equipment is capable of treating material over a broad size range, only falling off in efficiency in the very fine sizes. Gravity concentration is also inexpensive, generally free of environmental problems, and commercial equipment can process large tonnages of ore with a minimum of capital cost. As might be expected of an efficient and low cost process, the bulk of the tonnage quickly and inexpensively. Another obvious application is treating mineral deposits such as hematite and manganese ores that are sufficiently liberated after a minimum of crushing to allow production of a coarse concentrate that will meet market specifications. Except for hand picking and mechanical sorting, there is no competing process on coarse size material. Conversely, it is sometimes obvious that gravity concentration does not warrant consideration. Examples are ores that require very fine grinding to attain liberation, for ores where the minerals of interest have a gravity similar to the gangue, and ores that are strongly magnetic. Actually a mineral processing engineer may not know if gravity is the best way to concentrate an ore, but he should have little difficulty recognizing when gravity concentration deserves consideration based upon specific gravity differences and liberation gravity concentration has wide use. size. His challenge then is to At times its selection as the identify and test the applicable primary concentration process is processes, to develop a obvious. Low grade placer deposits metallurgical balance and flowsheet of tin, gold and beach sands usually for the best process, to estimate are only profitable because gravity production rate over the life of concentration is able to throw away the deposit and to make equipment

Jan 1, 1986