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By Robert B. Scott

The Dents Run Demonstration Project near Morgantown, West Virginia, was a cooperative venture involving the U.S. Environmental Protection Agency (EPA), the Water Resources Division (WRD)(1) of the West Virginia Department of Natural Resources (DNR), and the Christopher Division of the Consolidation Coal Company (CONSOL). The object of this project was to demonstrate pollution control methods and to clean up a 37.8 sq km (14.6 sq mi) watershed severely polluted by coal mine drainage. A study entitled, "Water Infiltration Control to Achieve Mine Water Pollution Control" (EPA-R-2-73-142),(2) was conducted by the Cyrus Wm. Rico Division of NUS Corporation for the grantee to determine the feasibility of utilizing remedial techniques to improve the Dents Run water¬shed. This study showed that the Dents Run watershed was discharging as much as 6,870 kg/day (15,100 lb/day) of acid; 1620 kg/day (3,560 lb/day) of iron 17,250 kg/day (38,000 lb/day) of sulfates; and 29,500 kg/day (64,900 lb/day) of total dissolved solids into the Monongahela River near Morgantown, West Virginia. This pollution was caused by the combination of borehole pump discharges from active underground mines, runoff from abandoned strip mines, and runoff from refuse dumps.

Jan 1, 1977

By L. Garner McDonald

The U.S. Bureau of Mines tangentially impacted potential coal-cutter bit shank materials against sandstone to investigate the potential of the materials to ignite natural gas by a friction-generated hot streak. The shank material samples were mounted in a 24-in, 550-lb flywheel, which was rotated at surface speeds of 400 to 900 sfpm. The sandstone was advanced toward the rotating flywheel at feed rates of 1 mil per impact. The atmosphere mixture was 7 vol pet natural gas in air. Three grades of polycarbonate resin, an ultra-high-molecular weight polyethylene, and a zinc alloy (ZA27) were among the potential materials. None of these materials caused ignition of the methane at any of the three test speeds (400, 600, and 900 sfpm), but the above materials do not have sufficient strength to hold a carbide tip during coal cutting. Of the materials having sufficient strength to hold a carbide tip, three nickel-based alloys proved less likely to cause a natural gas ignition than did iron-based alloys such as 4340 (a commonly used shank material for coal cutters).

Jan 1, 1992

By Stanislaw Trenczek

Natural hazards such as rock bumps, methane, coal dust explosions, airborne respirable dust, outbursts of gas and rocks, water, radiation caused by natural radioactive materials, spontaneous fires, and climatic hazards, occurring in the Polish hard coal mines, should be controlled. These hazards are characterized by different scale levels numbered from 2?5. To recognize the amount and levels of hazards, research works were carried out in 109 mining districts of mines belonging to Jastrzebska Spólka Weglowa, Katowicki Holding Weglowy and Kompania Weglowa. These are 86 % of all mines and could be regarded as representative of the majority of Polish mining. The hazards have been classified as regards the frequency of their occurrence as: commonly occurring ? with a frequency of 100 % (like airborne respirable dust and fire hazards), high occurrence frequency ? frequency from 60 to below 100 % (methane hazard ? 83.5 %, coal dust explosion hazard ? 92.0 %, and water hazard ? 99.1 %), medium occurrence frequency ? from 30 to below 60 % (rock-bump hazard ? 52.3 % and climatic hazards ? 51.4 %), and episodic occurrence frequency ? below 30 % (outburst of gas and rocks and radioactive hazards). The dynamics of effects of growth in hazard levels to their intolerable values is diverse. Some of them are passive in nature, which allows for longer observation of changes and appropriate early response (as for climatic and spontaneous fire hazards). However the majority of them take on the character of disasters, like methane or coal dust explosions and damage of the excavation structure ? as occurs after a rock-bump or rock outburst; and creation of an atmosphere unfit for breathing ? during open or spontaneous fires, or after gas outbursts containing methane. There are also latent hazards whose effects do not influence indeed a process of production; however they are detrimental to health when a worker is exposed for a long time to airborne respirable dust and radiation. For other types of hazards a level of danger may be only estimated. Since the systems monitoring allows a wider range of control, therefore, aside from rock-bump and methane hazards, there are monitored also fire hazards including measurements of other air parameters (velocity, pressure, humidity, temperature, O2, CO2 concentration). A few types of monitoring systems are used in Polish mines, like the monitoring systems for environmental parameters such as SMP-NT, SMP-NT/A, the telemetric systems CST-40, CST/A, including the computer-aided system for methanometry control officer SWµP, the computer-aided measuring systems KSP-1, KSP-2, KSP-2C, or the production and safety control system VENTURON. The underground part of the systems monitoring of natural hazards contains measuring devices and equipment for automatic control (power-off) of machines and electric devices in case of increased methane hazard. The surface part of the monitoring system allows the measuring data to be visualized and pre-alarm (warning) and alarm states to be displayed. Furthermore it makes it possible to archive and report the data and to control the underground supply and signalling devices. The EMAG Institute developed monitoring methods to extend a measuring range of monitored parameters (such as methane and fire hazards) as well as to monitor so far unmonitored hazards like dust hazards (by continuous monitoring of dust levels in mine air) and climatic hazards (by online monitoring climatic parameters of mine air).

Aug 1, 2013

By R N. Humphries

The aim of this paper is to question the need to develop bespoke monitoring and assessment methodologies and criteria, thereby ‘reinventing the wheel’, when designing and assessing the success of important natural habitat and ecosystem restoration schemes at mine sites in the UK and Australia. It draws attention to the existence and applicability of the Phase I Habitat, National Vegetation Classification (NVC) and Condition Monitoring methods in the UK and similar approaches used in Australia. These are long accepted established methodologies and have published accounts for describing, assessing and managing natural vegetation communities, habitats and ecosystems. They are often used at the environmental impact stage, but seemingly rarely, if at all, in restoration design and management at mine closure. Their application to mine restoration and closure is illustrated and discussed by reference to a surface coalmine in South Wales, UK.It is concluded that the application of a combination of the Phase I Habitat, NVC and Condition Monitoring methods is highly relevant to the expectations of the Convention on Biological Diversity (CBD) and its implementation in the UK, and probably in Australia too. The methodology and criteria described could be incorporated into the guidance and specified in the mining permits so that there is clarity as to the expectations and requirements for monitoring and assessment for bond release. Their use could be of wider application where there is a requirement to assess the success of restored CBD assets and ecosystems.CITATION:Humphries, R N, 2014. Why reinvent the wheel when there are established methodologies to aid the design and assessment of restored natural ecosystems on mined land?, in Proceedings Life-of-Mine 2014 , pp 675–692 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Brent A. Elliott, J. Richard Kyle

Texas is a major producer of industrial mineral resources required by the state’s ever-growing population that now exceeds 28 million. Texas typically ranks in the top three states for the value of non-fuel mineral production with a total value of $5.2 billion in 2017, accounting for 6.9% of the total US mineral value. Almost 90% of current Texas industrial mineral value comes from the production of cement, crushed stone, industrial sand, and construction sand and gravel. Construction material consumption is focused in the 25 metropolitan areas of the state with populations of > 100,000 residents. Industrial mineral consumption is dominated by the four most populous regions of the state—Houston, Dallas-Fort Worth, San Antonio-New Braunfels, and Austin-Round Rock—with an aggregate population of more than 18 million. More than 11,000 employees work in Texas mining and processing operations. Texas produces more crushed stone than any other state from more than 200 quarries; a similar number of operations produce sand and gravel. Specialty industrial sand production for use as proppants in hydraulic fracturing for enhanced petroleum production serves as an excellent example of how developments in one industry sector can markedly affect another industry; the production of industrial sand in Texas has markedly increased over the past decade, reaching $1.3 billion in 2014. With Texas’ population projected to reach 50 million by 2050, continuing in-state development and production of industrial minerals will be required to supply its residential, commercial, and industrial users. Favorable geology and economic factors provide opportunities for identification and development of new industrial mineral production sites.

By T R. Anderson, A R. Butler

Haymont (2012) notes that in parts of Australia significant areas of mining disturbance cannot be relinquished. In Queensland it has been estimated that by 2010, just 0.3 per cent 507 ha of mining disturbance had been rehabilitated to the regulator’s satisfaction (Short, 2015).One reason for this poor record is the presence of inappropriate, unachievable or unmeasurable rehabilitation targets (Glenn et al, 2014; Butler, Anderson and Sexton, 2015). In the authors’ experience in Queensland many mature operations have licence conditions that hinder the achievement of sustainable outcomes or prevent successful validation of rehabilitation success. This creates a lack of certainty for industry and a lack of confidence in the community that the sector can deliver good rehabilitation outcomes (Short, 2015).This extended abstract presents a framework approach that has been applied at two contrasting operations. Without the changes presented, the goal of progressive rehabilitation certification, reduction in financial assurance (FA) and a path to surrender at these sites would have been impossible. The framework can be adapted for use across different bioregions and commodities.CITATION:Butler, A R and Anderson, T R, 2016. Reassessing rehabilitation objectives and targets for mature mining operations in Queensland, in Proceedings Life-of-Mine 2016 Conference, pp 139–141 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Robert A. Bauer

Investigations of bedrock within subsided areas over abandoned coal mines reveal) very little disturbance of the bedrock. In areas that have surface subsidence of .3 to 1 m (1.0 to 3.25 ft), examination of cores from exploration drilling and investigations of the boreholes by means of closed circuit television have shown that fractures are spaced at least .9 to 3.6 m (3 to 12 ft) apart and are located within a zone 6 to 15 m (20 to 50 ft) above the collapsed area in coal mines 42.6 to 112.7 m (140 to 370 ft) deep. The dip of the fractures ranges from 25 to 60 degrees, cutting across nearly horizontal sedimentary bedding planes. Typical core recovery is 80 to 95 percent within the subsided areas and 100 percent outside the subsided areas.

Jan 1, 1984

By J. A. Bowers

THIS investigation of the effect of bottom shape and life on slag volume was carried out in two Lectromelt top-charge furnaces whose rated capacity is 1000 lb per hour. Unfortunately, just as the work [ ] was started, our steel tonnage was reduced approximately one half, therefore we did not accumulate enough data from which to draw any definite conclusions. Furthermore, the life of the linings in these furnaces was greatly decreased by intermittent operation, which was a further handicap in making a study of this kind. The weight of the heats from which the data were taken varied 1200 lb but all the information was corrected to the standard weight charge for these furnaces of 4500 lb. Almost all the heats were plain carbon; a few contained a small percentage of added copper.

Jan 1, 1947

By James F. McConnell, Charles W. Statler

Pennsylvania's existing large coal-fired units are limited to 2.0, 1.8, or 0.6 lb of sulfur per million Btu fired, depending on site location. Multi-stream coal preparation can be employed on system basis to extract the highest quality fraction of coal for use in units requiring the lowest sulfur. The middling fraction can be directed to units permitted higher sulfur. General Public Utilities Corp. has concluded that it is feasible to advance the state-of-the-art of heavy media coal preparation to produce an intensively cleaned primary product of 1.3 sp gr of less than 0.6 lb of sulfur per million Btu for the new unit and a middling product of 2.0 lb of sulfur per million Btu for existing units.

Jan 1, 1977

1. A passenger rickshaw in China. 2. A Pekin cart carrying coal, on dirt roads; the cost works out to 15 or 20 c. per ton-mile. 3. Coolie with wheelbarrow. This one has a small load, but barrow men carry ordinarily 250 lb., occasionally 400 if with a helper. He goes about 18 miles a day and the cost is about 25c. gold per ton-mile, though it varies widely. 4. Coolie delivering coal balls in Pekin. He carries about 65 lb. On some roads with a different arrangement a coolie carries 133 lb., making about one ton-kilometer per day. 5. Truck used by the Government Fuel Yard at Washington. Carries 71/2 tons in an hour as far as a barrow man carries 1/4 ton in a day.

Jan 8, 1928

By Henning Nielsen

SIX weeks ahead of schedule, the International Nickel Co. of Canada Ltd. has brought a 30-mile rail line into the newly born town of Thompson, Manitoba. Its construction spurs the development of a rich new mining region slated to become the world's second largest nickel-producing area-exceeded only by Inco's Sudbury, Ont., workings. Two mines, the Thompson and the Moak Lake, will be opened to meet International Nickel's scheduled annual production goal of 385 million lb of refined nickel by 1961. Accomplishment of this aim will mean an additional 75 million lb of the metal available to consumers. In addition, stepped-up out- put of Inco's Sudbury holdings may increase this figure by another 25 million lb. (For an earlier report on these developments see MINING ENGINEERING News, January 1957).

Jan 12, 1957

By Yi Luo

The efforts to mitigate longwall subsidence influences on various residential and farming structures by many coal mining companies have been successful in the recent years (Luo, et al, 2003). The successes were largely dependent on the accurate subsidence predictions, correct assessments of potential influences, appropriate design and implementation of the mitigation measures. However, such efforts for protecting large industrial structures are still very rare. In this paper, the successful assessment and mitigation of the subsidence influences associated with a very intensive dynamic longwall subsidence process on a large workshop are presented.

Jan 1, 2005

By Xiang (Frank) Chen, Mikhail A. Sokolov, Randy K. Nanstad

"Nickel-base Alloy 617 is being considered as a structural material for application in the secondary heat exchanger of the New Generation Nuclear Plant, a very high temperature gascooled reactor. Thermal aging of Alloy 617 plate and welds is being performed with tensile, Charpy impact, and fracture toughness tests conducted at temperatures to 950°C. Results of testing for thermal aging to 5,300 h have been obtained and are presented; varying effects of thermal aging temperature and time on fracture toughness are observed. The 9Cr-1MoV (Grade 91) ferritic steel is a candidate for structural applications in the sodium fast reactor. Fracture toughness testing of unaged Grade 91 steel has been performed to evaluate specimen size effects in preparation for future testing of the material in the thermally aged condition. Results for material in the mill-annealed and heat treated conditions are presented and show that this heat of Grade 91 steel does not indicate a small specimen bias on the fracture toughness Master Curve reference temperature.IntroductionThe behavior of advanced engineering materials will be a critical factor in the performance of Generation IV reactors. In the case of materials utilized for reactor internals and pressure vessels, the effects of irradiation and long time thermal aging are major issues. The environmental conditions for some of the Gen IV reactors are generally beyond present day reactor technology, requiring new experimental data as well as analytical predictions of expected behavior of candidate materials at conditions for which there are only sparse or no experimental data. The radiation environments and several key materials issues for some Gen IV systems are summarized in Section 5 of [l] as a starting point for modeling and microstructural analysis of Generation IV materials. More detailed descriptions of materials research and development needs and recommended activities for the SCWR, VHTR, and GFR are provided in references [2, 3, 4], respectively. Mansur, et. al. provide an interesting comparison of materials needs for Generation IV reactors to corresponding needs for fusion reactors and spallation neutron sources in [5]. The two primary candidate reactor systems currently undergoing significant research and development by the U.S. Department of Energy (DOE) are the New Generation Nuclear Plant"

Jan 1, 2012

By G. M. Ault, G. C. Deutsch

The paper reviews the efforts made to utilize powder metallurgy to solve problems encountered when using alloys at high temperatures. The following subjects are discussed: comparison of wrought and sintered super alloys, sintered aluminum powder, porous materials for transpiration cooling, molybdenum, and cermets. TODAY, powder-metallurgy techniques are be-JL coming increasingly important, producing materials which at the present time cannot be made by any other method. Among these materials are high melting-point metals such as tantalum and tungsten, porous metals for filters and lubricant-containing bearings, electrical contacts and electrodes (i.e., tungsten-copper), cutting tools of the cemented carbides, and magnet alloys. In addition, the powder-metallurgy industry has grown because, through the application of its methods, shaped parts, such as gears, can be produced at tremendous rates with a low scrap loss in comparison with manufacture by casting or forging and machining. In the past few years, by utilizing powder metallurgy, several approaches to the problem of high temperature materials have been investigated. In this paper the authors will review some of the studies on application of materials having properties above 1350°F. Since their experience lies in the aeronautical field, possible uses of powder-metallurgy techniques in the production of aircraft en- gines will be emphasized. A large portion of the work is classified, but such a restriction has not eliminated any field from discussion, although limiting the amount of detail it is possible to present. The development of high temperature alloys from powders and porous metals for cooling will be discussed as well as research done on molybdenum and molybdenum alloys, cermets, and intermetallics. Some studies on the utilization of cermets will be considered along with special problems that have been revealed through these investigations. Special interest in certain factors of sintered aluminum powder (SAP) makes it desirable to discuss this material although its use temperature is below the 1350°F limitation set for this paper. High Temperature Alloys from Powders In general, components made from powders for room-temperature application have been investigated with the primary purpose of taking advantage of the high production rates and economies made possible by powder metallurgy. From the standpoint of properties, the ojective of the powder metallurgist has been to obtain a product comparable to the cast or wrought product that is to be replaced. Comparisons of the properties of alloys made by powder-metallurgy methods with those of similar compositions made by casting and forging are reported in the literature.12 In many cases equivalent

Jan 1, 1955

By J. C. Wynn

J.R. Hillebrand From the abstract, "A realistic ore deposition model to serve as a conceptual framework." Further, on page 246, "The first area of study was the Josephine peridotite, now identified as an ophiolite terrane, located in northern California and south-western Oregon (Fig. 3). Here, it was felt that we could test the models shown in Figs. 1 and 2 and, if successful, expand the model and test it in other chromite districts in the US and around the world." My comments refer only to chromite deposits in Europe and the Middle East. First, I question that may chromite deposits occur in the idealized ophiolite section shown in Fig. 1. Second, although some podiform deposits (referring to morphology) have been important (Guleman, Turkey, for example), the stratiform deposits are of greater importance in tonnage and frequently grade. Examples include Nada, Yugoslavia; Bulqiza, Albania; Xerolivado, Greece; Saranovsk, Russia; and Abdasht, Iran. Reply by J.C. Wynn Mr. Hillebrand raises two issues that deserve a serious response. One issue is basically subjective and the other is ultimately political. First, the question of where (and how many) podiform chromite deposits are found in the idealized ophiolite section of Dickey (1975). The Dickey model is still perhaps somewhat controversial (Panayoutou, 1980), but our experience in the Josephine ophiolite of northern California (Wynn, 1980; and Albers, 1983) shows that the model works well there. Virtually all the chromite is found in dunite lenses in the tectonite peridotite (harzburgite). Since there are few complete ophiolites exposed in the world, the model will probably never satisfy everyone. The degree of acceptance is a function of any individual's subjective experience. Second, it is well known that stratiform chromite contributes more than 95% of the chromite reserves presently known in the world, and it could be reasonably argued that there is no point in exploring for or exploiting podiform deposits further. The title of the paper, however, was in part 'strategic minerals geophysical research'; chromite is considered a strategic and critical mineral of the US and many other industrialized nations. Stratiform deposits in South Africa and Zimbabwe account for most of the chromite reserves in the world. Unfortunately, experience in modern times with substantial price fluctuations and even resource cartels dictates the wisdom of identifying and maintaining a national chromite reserve, irrespective of the cost. An improved exploration methodology is an essential element in this strategic objective. References Albers, J.P., 1983, "Geological and Geophysical Studies of Chromite Deposits in the Josephine peridotite, California and Oregon," US Geological Survey Bulletin 1546 A-D, 118 pp. Dickey, J.S. Jr., 1975, "A Hypothesis of Origin for Podiform Chromite Deposits," Geochimica et Cosmochimica Acta, Vol. 39, pp. 1061.1074. Panayiotou, 1980, Proceedings, International Ophiolite Symposium, Cyprus, 1979, 781 pp. Wynn, J.C., 1980, "Exploration Geophysical Methods and Strategies, and Their use to Locate and Assess Small Mineral Deposits," Chapter 12 of Meyer and Carmen, eds., The Future of Small Scale Mining, McGraw-Hill, New York, pp. 75-83.

Jan 12, 1983

By J. D. McKay

The Bureau of Mines devised a column flotation technique using either fine or coarse bubbles and compared it with conventional flotation on a Montana chromite ore. On deslimed ore, fine-bubble column flotation produced a 44.7-pct-Cr203-grade rougher concentrate with 87-pct recovery, compared with 43.8- and 43.5-pct-Cr203-grade rougher concentrates with 85- and 77-pct recovery for coarse-bubble column flotation and conventional flotation, respectively. On undeslimed ore, coarse-and fine-bubble column flotation produced rougher concentrates containing approximately 41.5-pct-Cr203 with 95-pct recovery, exceeding conventional flotation which produced 35.6-pct-Cr203-grade concentrates with 87-pct recovery.

Jan 1, 1985

"INTRODUCTIONThe Department of Energy, Mines and Resources has recently developed two automatic controls for use in the cyanidation circuits of Canadian gold mills. These controls are the alkalinity probe and the Continuous Cyanide Titrator both of which are discussed in the paper ""Instrumentation in the Cyanide Process"".(1)In May 1966 these process controls and associated recording equipment were installed in the Bralorne mill by two Scientific Officers from the Department. The object was to determine if the equipment was amenable and applicable to this particular circuit. The purpose of this paper is to discuss the performance of the equipment over a test period of 4 months.CONCLUSIONSThe results of test work to date indicates that both the Conductivity Probe and the Continuous Cyanide Titrator would be an as set to the operation of the Bralorne mill.The conclusions are generalized as follows:-(1) At a milling rate of 100, 000 tons per year the expected reductionin reagent consumption would give a direct saving of 37, 660 lbs of lime@$0.030 per lb and 15, 790 lbs of sodium cyanide@ $0.175 per lb. Such cost savings would pay for the equipment and installation costs within a 30 month period"

Jan 1, 1967

By C. E. Jordan

The Bureau of Mines is conducting research into the pneumatic recovery of coarse mica and has used this method to produce mica concentrates that contain more than 90 percent mica. This research is being carried out pursuant to the Bureau's objective to develop technology that will help maintain an adequate supply of minerals and metals to meet national economic and strategic needs. Researchers used a Bureau-designed system of crushers, screens, and zig-zag air classifiers to concentrate coarse liberated mica particles from mica-bearing materials. This pneumatic system was used to concentrate four mica ores from Arizona, North Carolina, and South Dakota and three waste tailings from Alabama, Georgia, and South Dakota. Using these samples, it was demonstrated that plus 65-mesh size mica can be effectively recovered by the pneumatic method. Not only were the concentrates high in mica content; it was also demonstrated that this method can be used to recover up to 78 percent of the mica that was originally contained in the samples. Because it is a dry concentration method, the pneumatic beneficiation technique may be advantageous in areas where water resources are limited.

Jan 1, 1980

By M Sykes

Gold was initially discovered at Ballarat in 1851. After initial alluvial mining, underground quartz mining commenced in 1853, continuing until 1918. The historic miners were considered to be capable of mining anywhere in the world after overcoming the difficult conditions within the Ballarat goldfields. Whilst mining has changed dramatically since the early 1900s the challenges with underground mining at Ballarat have not. Modern pumping systems cope with the moderate water inflows. However, modern machinery and efficient mining methods influence opening sizes and extraction techniques. In some cases modern techniques have accentuated the challenging ground conditions and complex orebodies that were faced by the historic miners. As the Ballarat East project has progressed towards production, technical challenges relating to geomechanics and mine planning are being resolved resourcefully.

Jan 1, 2008

By R F. Cota, C Freeman, A Heberle

"The Lamego mine is an underground gold mine in the Iron Ore Quadrangle in Minas Gerais state, Brazil. The mine produces 48 to 50 koz per annum, as part of the larger Cuiabá-Lamego Complex. This combined unit is AngloGold Ashanti’s largest gold producer in the Americas, contributing with 310 to 320 koz per annum.The mine started production in 2009, utilising cut-and-fill mining methods.A mining method change was trialled in 2014, introducing open stope methods. The key benefits proposed from this change are considered to be: improved safety by eliminating re-entry mining methods reduced mining costs/increased productivity from utilising bulk-mining operations.The results from the trial were encouraging, and open stoping participation expanded beyond a trial.Production from open stope areas reached 180 000 t (40 per cent of total run-of-mine; ROM) in 2015. While the change in mining method resulted in higher production rates, it also introduced a critical issue in terms of stope recovery rate.Average underbreak (unplanned loss of ore) in the larger open stopes reached 21 per cent in 2015. To manage this ore loss, a project targeting higher recovery was structured with three primary components: analyse current performance to define contributing factors (design process gaps, operating practices) investigate corrective actions apply corrective actions and maximise team engagement to ensure changes become standard practice.Within six months of commencement, a range of contributing factors had been identified, and the majority of the associated corrective actions implemented, including increased team engagement to ensure changes were not ‘once off’ actions.The outcomes show a clear reduction in underbreak (average ~12 per cent for 2016), with further improvement opportunities identified. The challenging target is now to achieve a further reduction to 10 per cent underbreak as the average for 2017. The results contributed 1400 oz and additional US$ 0.5 million to the cash generation profile for 2016.CITATION:Heberle, A, Freeman, C and Cota, R F, 2017. Increasing stope recovery in an underground gold mine by using effective analysis, corrective action and employee engagement processes, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 117–122 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017