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By Robert E. Gray

The vat leaching operation at the Yerington Mine was started in October, 1953. The original plant facilities consisted of primary and secondary crushing, eight leaching vats, precipitation launders, sulfuric acid plant and the necessary maintenance, warehouse and administrative facilities. By 1961, 35,000,000 tons of oxide ore had been removed from the mine exposing the underlying sulfide ore body. A 5,000 ton per day concentrator was constructed and put into operation to treat the sulfide ore in November, 1961. The original crushing plants were used for both oxide and sulfide ores. By adding a third crushing shift for six days per week, the treated ore was increased from 12,000 to 17,000 tons per day. To balance the oxide and sulfide ore reserves, the concentrator was expanded to 13,500 tons per day in 1967. Again, no additional crushing facilities were added. It was anticipated that the treatment rate of oxide ore would be reduced from 12,000 to 9,000 tons per day. Instead, the addition of two crushing shifts per week, and improved operating procedures, increased the treated ore to 26,500 tons per day, 13,000 tons to the vat leaching and 13,500 tons to the concentrator.

Jan 1, 1975

By James Wm. White

Computer-based mine management systems are being used in many surface mines to assign haul trucks, track equipment and manage information. Advances in digital communications allow these systems to be used in underground operations. Underground mine management systems help maximize production by providing gains in equipment and manpower use, drawpoint equalization in block caving operations, preventive maintenance and safety. Current systems use allocated or "locked" train and load-haul-dump (LHD) dispatching. Allocated dispatching rarely optimizes open pit product' on. But it offers an efficient mode of operation underground and where options are more limited. The primary objectives of underground mine management systems are to maximize production and mini¬mize contention time through allocated train, truck or LHD dispatching, traffic control, equipment monitoring and comprehensive reporting. The main components of an underground mine management system include: ? A central computer (personal computer or worksta¬tion) in a central control center. It sends instructions to train, truck or LHD drivers and allows dispatcher interaction. ? A field computer system (FCS). This consists of a touch-screen graphics console (GC) and mobile hub - on each train, truck or LHD to receive and display instructions from the central computer and accept driver input. ? A data radio network based on leaky feeder (data, voice, video) or microcell radios (data only) and advanced token-ring technology. This passes information between the central computer and the FCSs. ? Radio frequency (RF) tags mounted at boxes, weigh bridges, tips and rim tunnel main haulage ways to locate trains or LHDs (Luke, 1993). Such a management system must be in place before implementing computer-based dispatching (Vagenas, 1991) for production optimization.

Jan 1, 1997

Shallow ore deposits are mined by surface methods but a depth is reached in the case of most deposits after which underground methods are applied for the extraction of the remaining ore. The determination of this depth and its analysis is the subject of this paper. In order to determine transition depth from open-pit to underground mining on the basis of the allowable and economically feasible overall stripping ratios, an economic-mathematical equation is first introduced. Using the achieved equation and an analytical procedure on a particular two-dimensional hypothetical tabulate deposit, an effective formula is then established. The formula introduced here, together with the procedure adopted, could be used in all similar mining situations by the mining design engineer.

Jan 1, 2010

By E. F. ‘Pat’ Nelson, Richard Broom

Our portion of this afternoon’s session is dedicated to the operation of automatic process control associated with small to medium size primary or SAG milling circuits. In recognition of the subject matter of this symposium, specifically precious metals, our historical reference is Rosario Dominicanna in the Dominican Republic, one of the largest gold producers in the Western Hemisphere. Plus a backward glance to review very briefly the initial performance of the big primary mills at Island Copper in British Columbia and Pima IV in Arizona. We will then get to the subject at hand with a discussion of a retrofit control logic recently installed on a 5000 hp primary mill. The focus of this review is the simple, inexpensive, and cost effective character of this retrofit installation.

Jan 1, 1984

By Roland C. Walker

Traditional headed rebar has existed in the mining industry as a ground support product for many years. The head of a rebar bolt is most commonly produced by hot upset die forging. Upset die forging produces a rugged, simple head that performs well. Certain elements of the head must comply with regulatory standards, such as ASTM F432-95, which offers a standard test procedure to ensure quality of the product. The head style produced by all major manufacturers has been optimized to reduce manufacturing costs, provide greater miner safety and provide an excellent performing product. Observations were made in some mines of heads failing under in-situ loading. These observations could not be replicated according to the ASTM testing method. This paper highlights the problem and how a solution was developed. The development includes pictures of in-situ failures from the underground operations, laboratory replication tests indicating how this loading occurs, and then the use of this calibrated test method to validate the new design created.

Jan 1, 2009

By Jacques Villeneuve, Stéphane Brochot, Jean-Claude Guillaneau, Marie-Véronique Durance

Since 1986, BRGM has been developing a powerful process simulation software package, USIM PAC. These last years have seen significant developments in mineral processing technologies, particularly in hydrometallurgy, bio-hydrometallurgy and mineral liberation. The new version of the simulator, USIM PAC 3.0, incorporates these modem-processing fields. Its structure and tools allow the user to take into account, at the same time, a wide range of technological, economical and environmental aspects. The improvement of the existing features and the introduction of new unit operation mathematical models and tools such as the supervisor, global optimization, workshop model or chemical reactions contribute to a global approach in mineral processing design.

Jan 1, 2002

This paper reviews the historical literature and the author's experience with regard to the effect that the selection of grinding ball size or sizes has on ball mill grinding efficiency. The conclusions presented provide guidelines for single and multi-size charging prac- tices in commercial milling operations.

Jan 1, 1998

By K. L. Branham, D. W. Steeples

Surface collapse over abandoned sub- surface coal mines continues to be a problem in many parts of the world. High-resolution P-wave reflection seismology was successfully used to locate water-filled cavities in a 1-m (3-ft) thick coal seam at depths of 9 m (29 ft) in southeastern Kansas. A dominant frequency of 275 Hz was attained enabling us to delineate the top of the coal seam. To our knowledge, this study is one of the first to locate water-filled coal mine cavities at depths of less than 30 m (100 ft) wing high-resolution P-wave seismic reflection techniques.

Jan 1, 1987

By I. Iwasaki, X. Cheng

A series of batch flotation tests was performed on chalcopyrite-quartzite, on pyrrhotite-quartzite and on chalcopyrite-pyrrhotite-quartzite mixtures. Pulp potential measurements in the flotation tests with single sulfide minerals indicated that each sulfide mineral had its own optimal potential range for flotation. When these results were used to select the potential ranges for the separation of the two minerals from their mixture, their flotation responses changed, and the selectivity of separation was adversely affected. A possible mechanism involving surface alteration through galvanic interaction is discussed, and a method to improve the selectivity of flotation separation is proposed.

Jan 1, 1993

By Eric W. Johnson

In the late 1950's a low-grade copper ore zone was outlined at the fifty-year-old McIntyre Porcupine Mine in Northern Ontario. Following this an independent copper circuit was installed in the existing gold mill. The nature of the operation decreed that capital expenditure be a minimum. To this end, in order to resolve the problem of storing and grinding two separate ores, it was decided to install a divider in the existing 4000 ton capacity fine ore storage bin and to replace ten conventional feeders with sixteen Mexican feeders. The article describes a successful application of the Mexican type feeder.

Jan 1, 1968

By C. Roldan, C. Garcia, J. D. Miller, C. L. Lin

The ultimate recovery in a heap leaching operation is related to the degree of exposure of the valuable minerals in comminuted particles. Recently, high-resolution cone beam x-ray microtomography (XMT) has been used to determine this parameter. XMT technology consists of examining the extent of mineral exposure for each size fraction of ore in 3D, then, by algebraic calculations, the ultimate recovery can be estimated for different particle size distributions (PSD). To confirm the usefulness of the XMT technology for mineral exposure analysis, column tests were performed to determine ultimate recovery using three PSDs for two composites obtained from the copper heap leaching operation at Zaldivar-Chile.

Jan 1, 2003

By Arash Nikvar-Hassani, Lianyang Zhang

To address the drawbacks of the conventional portland cement/fly ash (PC/FA)–based cementitious material currently used in practice to construct pumpable roof supports (PRSs), a novel cementitious material has been developed based on geopolymerization technology. The novel cementitious material is comprised of two pumpable grout streams: Stream 1 is a slurry composed of pozzolanic material and high-calcium additive and stream 2 is an alkaline solution comprised of a gelling agent. Biopolymer has been added to the second stream to provide ductility to the geopolymer cementitious material. In the laboratory scale, systematic experiments have been carried out to investigate the viscosity, setting time, and uniaxial compressive strength (UCS) of the new cementitious material and develop the right recipe for field applications. By collaborating with industry and the National Institute for Occupational Safety and Health (NIOSH), full-scale PRSs have been constructed and tested. The results show that (1) the novel cementitious material based PRSs has much higher peak UCS and similar or higher residual strength than the conventional PC/FA-based PRSs; and (2) unlike the PC/FAbased cementitious material, the novel cementitious material shows good long-term durability with nocracking/disintegration when exposed to air.

Jul 1, 2023

By Ann M. Hagni

One of the most costly factors in the production of aluminum is the consumption of energy in the form of electricity. Energy consumption is increased as refractories in the Hall-Heroult reduction cells are corroded by penetration of the fluxes cryolite (Na3AlF6) and villiaumite (NaF). To decrease thermal conductivity and refractory waste, protective barrier linings are installed. Dry powder barrier linings form stable reaction products at cell operating temperatures. Four dry powders composed of vermiculite, corundum, wollastonite, and anorthite are characterized mineralogically by X-ray diffraction, reflected light microscopy, scanning electron microscopy, and cathodoluminescence microscopy in this research project.

Jan 1, 1998

By L. Barry Phelps

The complexity of surface mining operations is increasing as attention is directed towards mining larger tracts of lower grade, higher cost deposits. Large tonnage requirements from these mines necessitate utilization of many large pieces of equipment. This equipment must be utilized efficiently, with production maintained at or near designed capacities. Basically, the problem is to select, size, and schedule equipment to maximize profits and minimize adverse environmental impacts (Anon., 1977). The time, manpower, and cost limitations required to analyze a wide variety of situations and alternatives in planning surface mines have been sidestepped with the application of simulation methods using a digital computer. Since a simulator can be programmed to represent the situations which are to be analyzed, many alternatives can be evaluated in a relatively short time. Input variables are easily changed and the resulting changes which take place in the system can be analyzed. When standard methods of analyses are applied, weeks and many man-hours are involved in analyzing large-scale mining operations. At the same time many simplifying assumptions must be made since these operations are dynamic and transient. Hence, it becomes difficult to make sound engineering decisions and take proper and timely corrective action in the absence of simulation methods. This chapter is concerned with the application of one such method, namely, the open-pit materials handling simulator (OPMHS) developed by the Mining Engineering Section, The Pennsylvania State University (Manula, Albert, and Ramani, 1977).

Jan 1, 1979

By Tamás Megyeri, Dániel Borbély, Vera Szánto, László Kovács

"Upon completion, the Bátaapáti deep underground radioactive waste repository complex (National Radioactive Waste Repository - NRWR) will provide safe final disposal for low and medium-level radioactive waste from the Paks Nuclear Power Plant in Hungary. The waste emplacement is in progress and one of the main concerns related to the development is ensuring a feasible plan is in place for permanent repository closure. Detailed hydrogeological observations and safety assessments revealed that the clay filled fault zones penetrated with the access tunnels play determinant role in the long-term confinement performance of NRWR, so they need to be plugged. Detailed mechanical analysis and numerical modelling of the tunnel constructed through a fault zone is presented here to gain a better understanding of the rock mass and rock support behavior. The effect of stress reflection is demonstrated and its consequences are described in detail. A recommendation is given for tunnel support design in such conditions. INTRODUCTION Crossing fault zones is a challenging task during tunnel construction and can lead to failure if not properly accounted for during design and construction. These failures are can be caused by high water inflow or stability loss of the rock mass surrounding of the tunnel (examples can be found in CEDD, 2015). The prediction of the magnitude and development of displacement has a considerable impact on issues during tunnel construction. Changes of rock mass stiffness or structure ahead of the face, to a great extent influencing stresses in the vicinity of the tunnel and thus deformations (Steindorfer, 1998). Further research with numerical simulations was carried out, and the qualitative and quantitative evaluation of displacement vector is presented in (Grossauer et al, 2005). The concern associated with crossing fault zones was considered during the design of the Bátaapáti deep underground radioactive waste repository complex (NRWR) in Hungary. In the case of NRWR project, the fault zones have an impact on maintaining the stability of the surrounding rock mass as well as the final sealing of the repository. As part of the final closure design, a complex numerical modelling program was completed to gain a better understanding of the mechanical behavior of the rock mass and the monitoring observations during construction. Even though the need for the presented study is closely related to the NRWR project, the results can be used in any project related to fault zone crossing. The methodology used to better understand the impact of crossing fault zones for the NRWR project is presented in this paper. First the project background is introduced including an overview of the underground facilities, the aim of the repository, and the construction experience gained from the first crossings of the fault zones. After that the in-situ and laboratory testing is summarized. The numerical modelling methodology is detailed in the next section. Not only the outcome of the model is presented, but the results are compared with the experience and observations made on site. Since a good agreement is found between the actual and the modelled behavior, the conclusions are based on the validated result. To fulfill the aim of the paper, the stress reflection concept is introduced to explain the mechanical behavior of the fault zone and the rock support; furthermore straightforward suggestions are made for rock support design."

Jan 1, 2016

By Y. T. Auck, M. E. Kukura, L. G. Stevens

At its Technical Development Center in Tucson, Arizona, the UOP Mineral Sciences Division operates a completely integrated pilot plant testing a proprietary process for the extraction of nickel from limonite/saprolite ores. The process is based on the reductive roast- ammonia leach procedure now employed in several plants around the world. The process improvements are such that nickel extractions well above that experienced in these processes are possible, particularly on the more garnieritic/saprolitic ores. This paper will describe the process and the results of process development studies. The data show that pilot plant results confirm those obtained on the smaller laboratory and bench scales of experimentation.

Jan 1, 1979

By R. M. Geisenheyner

We are in the midst of a transportation revolution. From the Wright Brothers to the SST. From the Toonerville Trolly to the 120-mile-an-hour Northeast Corridor train. From Christopher Columbus to Neil Armstrong. There is another side to this revolution and it is going on every day at our mines and factories. We call it bulk distribution. Perhaps ordinary sounding, but every bit as exciting as those other transportation innovations. Basically, we have gone from bag to bulk, and in the process reached that Last Frontier in manufacturing cost savings. By revitalization of our distribution system, we have made it possible for our mines and factories to realize fully the vast economies of spage-age manufacturing techniques and accomplishments. The pacesetters in this distribution revolution have been you gentlemen, the producers and shippers of dry mineral products. In this area bulk distribution grew up. And here most of the current innovations are being introduced. Management of your industry was early to realize the economic advantages of bulk distribution. Distribution costs of your products comprises a sizeable, portion of the selling price and management is sensitive of any developments which may even slightly reduce the cost of transportation, marketing or the exploration of new frontiers.

Jan 1, 1969

By Randy J. Mikula

Cleaning of low-rank coals can have several meanings, depending upon the definitions of the terms "low rank" and "cleaning." In general, low-rank coals would be lignite or subbituminous according to the ASTM classification. For the purposes of this summary, cleaning is defined to be any process which materially reduces the proportion of inert material in the coal. For low-rank coals, this often means a reduction in moisture content since moisture is the major inert component in these coals. A brief discussion of conventional cleaning processes is included, as is an extensive reference list.

Jan 1, 1991

By X. Wu, M. G. Karfakis, K. Y. Haramy, B. T. Brady

A quantitative evaluation of damage caused by ground motions associated with strong roof caving is presented. The strong roofs are modeled as either cantilevering or bridging beams over continuous elastic foundations that are subject to an exponentially distributed vertical stress. Major factors influencing roof caveability and strain-energy buildup are identified and investigated. A methodology for the evaluation of strain-energy accumulation caused by, an overhanging roof is presented. The potential for mine tremors is determined in terms of the local Richter magnitude (ML), which depends on the seismic energy transformed from the stored strain energy that is released when the roof fails. A particle-velocity model is applied to estimate the damage area associated with roof collapse. A case study from a Utah coal mine shows that estimations of bump severity and the damage area agree well with field observations.

Jan 1, 1997

By E. T. Sugar

English China Clays, the world's largest producer of China Clay, has its main production capacity in the South-West of England, where a complex of pits, refining plants, dryers and ports covers an area of approximately 100 square kilometres. The possibility of a computerised information network was first considered in 1980. The system was required to provide information at the central level and also at local plant level to improve co-ordination and control. Immediate access by any authorised user, and flexibility of interrogation were important aims. A small micro-based prototype system was implemented in 1981, and later that year development of the mainframe system commenced. This latter system will provide at least one terminal in every works location and will allow inter-communication of laboratory test data as well as detailed stock levels and production data. An integrated system for order processing will allow stock levels to be monitored in relation to anticipated requirements. The system has been developed by the Data Processing Department using the IDMS database package running on an ICL ME29 mainframe. It was decided to use microcomputers as terminals, which although more complicated because of protocol emulation allows stand-alone applications to be run on the same equipment. Those applications concerning Production Planning are outlined in the paper. Communication on the network is by synchronous transmission over dedicated lines. All data is stored on the central database with terminals accessing it in a star configuration. The system is currently partially implemented with 30 available screens at 18 separate worksites.

Jan 1, 1986