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By Ramazan Comakli, Cemal Balci, Nuh Bilgin, Hanifi Copur, Can Polat, Deniz Tumac

"Application of mechanical excavators for rock excavation in both civil construction and mining engineering fields has increased significantly in recent years. Prediction of the excavation performance of any mechanical excavators – tunnel boring machines, roadheaders, impact hammers, continuous miners and shearers for any geological formation is one of the main concerns in determining the economics of a mechanized mining and/or tunneling operation. A new portable linear rock cutting (PLCM) device was developed in the Mining Engineering Department of Istanbul Technical University and supported by The Scientific and Technological Research Council of Turkey (TUBITAK-112M859). The PLCM is used for cutting small core or block rock samples by a real-life mini disc cutter. The results from the PLCM are compared with the results obtained from the full scale rock cutting tests and theoretical model. It is found that there is reliable correlation between test results obtained from both cutting tests and theoretical model. 1. INTRODUCTION Mechanical excavators are currently the only alternatives to drill and blast due to higher production rate, increased safety, uniform muck size, less roof support, easier ventilation, continuous rather than cyclical operation, and possibilities for automatic control. The most of large civil tunneling and some mining projects are now carried out by mechanical excavators rather than drill and blast methods. Mechanical excavators can be categorized into two main groups: full-face and partial-face machines. Full-face machines such as tunnel boring machines excavate the face in one mode at the size of the cutterhead. Due to their cutting mode, the shape of the face profile by the full-face machines can only be circular. As for partial-face machines, the cutterhead is attached at the end of a boom. The face profile excavated by the partial-face machines can be from circular to horseshoe shape due to the cutting mode of the boom."

Jan 1, 2016

By Bryan Morris

Quebrada Blanca (QB) is a copper project located in the semi-arid Andean highlands of northern Chile. The operation is situated 170 km ( 105 miles) southeast of the port of Iquique and 30 km (18 miles) west of the border with Bolivia, at an altitude of about 4300 m (14,000 ft) (Fig. 1). The QB ore body is a secondarily enriched porphyry copper deposit containing reserves of 85 Mt (93 million st) grading 1.3% copper. Underlying the enriched zone is a significant primary ore zone containing several hundred million tons grading about 0.5% copper. In the late 1970s and early 1980s Falconbridge and its affiliates spent $20- $30 million exploring the deposit and conducting feasibility studies. Falconbridge, however, decided not to develop the property. It was returned to its owners, Empresa National de Mineria (ENAMI), a Chilean state mining corporation. In 1988, ENAMI announced its intention to privatize the property through public bidding. Cominco Resources, then 61% owned by Cominco Ltd., examined the property and the extensive data base developed by Falconbridge. In conjunction with its parent company, Cominco Resources submitted a proposal to ENAMI to construct an open- pit mine, with heap leaching and solvent extraction/electrowinning (SX-EW) processing facilities. The plan would use patented heap leaching technology developed by Sociedad MineraPudahuel (SMP), a privately owned Chilean mining company. At that time, a $150-million project that would produce about 45 kt/a (50,000 stpy) of cathode copper was envisaged.

Jan 1, 1993

By K. V. Raj, C. A. Berry, A. T. Weakley, A. L. Miller, P. R. Griffiths, D. A. Parks

Diesel particulate matter (DPM) has been classified as a carcinogen to humans by the International Agency for Research on Cancer. As a result of its potential carcinogenic nature, DPM exposure is regulated by the Mine Safety and Health Administration. Currently, diesel emissions in the workplace are monitored by collecting the aerosol onto filters, which are then sent to a laboratory for thermal-optical analysis using the NIOSH method 5040. This process can take days or even weeks, and workers can potentially be exposed to excessive levels of DPM before the problem is identified. Moreover, the delay involved in getting the loaded filter to the lab inevitably means the loss of some of the more volatile organic carbon. To remedy this delay, researchers from the National Institute for Occupational Safety and Health are seeking to develop a field-portable, real-time method for measuring elemental and organic carbons in DPM aerosols. In the current study, the use of mid-infrared spectrometry was investigated. It is believed that mid-infrared spectroscopy is more suitable for use in a real-time field-portable device than thermo-optical analysis methods. This article presents a method for measuring organic carbon (OC) and elemental carbon (EC) in DPM for a broad range of OC/EC ratios. The method has been successfully applied to laboratory-generated and mine samples.

By Terry W. Engelhart

"A computer-based approach to online supervisory control and operations management of bulk materials handling terminals". This paper describes an integrated computer facility supporting the functions and responsibilities of shift operations, scheduling, maintenance and management using real-time interactive techniques. The functions and responsibilities as related to coal export terminals are specifically addressed, although these functions would be equally applicable to other terminal configurations and other commodities. A discussion of the resulting benefits are presented: - throughput efficiency - long-term planning and scheduling, using simulation - operations monitoring and protection - demurrage/despatch optimization - preventative maintenance - operational productivity

Jan 1, 1982

By C. Hansen, J. Killey

This paper discusses the replacement of AEROFLOAT ® 1 25 promoter by AERO ® 5688 promoter at Sonora Mining Corp.'s California Mother Lode concentrator. Flotation concentrate is trucked 120 miles to a leach plant in Nevada, so the reduced mass resulting from higher gold grades and reduced talceous gangue and barren pyrite resulting from this change in promoters has brought about a major decrease in shipping costs. Preliminary laboratory testing indicated that free milling gold and controlled amounts of pyrite could be floated using Aero 5688 promoter with reduced dosages of Aero 350 xanthate.2 Extensive plant trials confirmed that the new reagent suite could indeed maintain gold recoveries while reducing total mass. Improved froth characteristics also improved operating flexibility in treating various ore types, and overall reagent costs have been reduced.

Jan 1, 1991

By Adam Levy, Thomas Novak, Sampurna Arya, Joseph Sottile, Kozo Saito

The use of a woven wire-mesh screen as part of a flooded-bed dust-scrubbing system is popular in the underground coal mining industry. It is used in combination with a demister (mist eliminator) to remove dust from the dust-laden air. A study was conducted to measure the pressure drop across a flooded-bed, wire-mesh screen at different airflow rates in one-phase (dry) and two-phase (wet) conditions. Two empirical relationships between pressure drop and air velocity were developed for dry and wet conditions, respectively. In both cases, the form of the empirical relationships was found to be similar to relationships given by Sabri Ergun for high velocity, non-Darcy, single- and multi-phase flow through porous media. The experiments were repeated on a reduced-scale model of the wire-mesh screen, and the pressure-velocity relationships obtained from the full-scale prototype experiments were tested. The test results show validation of the full-scale empirical formulae on the small-scale model with an insignificant variation. This paper presents the empirical equations for pressure drop across the wire-mesh screen in dry and wet conditions. Researchers can use these equations as a tool to predict total pressure drops for wire-mesh screens of different scale sizes.

By J. Drelich

The wetting behavior of liquid polymers at solid surfaces and the adhesion forces involved at polymer-filler interfaces should always be considered in the fabrication of high quality polymer composites, including those made with mineral fillers. Spontaneous polymer spreading over the filler surface is a basic condition in the fabrication of the polymer-mineral composites. In this regard, the wetting and adhesion characteristics of polymer-mineral systems are reviewed in this contribution. It appears that several aspects of wetting phenomena at mineral filler surfaces are not well described in the literature and require further systematic study. Specifically, it is clear from this review that efforts should be made to determine the effects of mineral surface contamination (including surface hydration) on wetting and adhesion phenomena, and to determine the wetting characteristics of molten polymers at mineral filler surfaces. It is expected that any improved fundamental understanding of wetting and adhesion phenomena for the polymer-mineral composites will provide the basis for further technological development.

Jan 1, 1995

By Margaret Armstrong

The increasing cost of developing new mines and the need to mine more marginal deposits have led mining companies to use more sophisticated estimation methods such as kriging. But until recently, coal mining companies have shown little or no interest in these techniques. However, the stringent quality controls which are now placed on coal have led to a surge in interest in improved estimation methods. This can be seen from the -, number of research projects by private companies and governmental agencies on the application of geostatistics to coal reserve estimation. At present, most of these programs are centered on the problem of estimating the tonnage and the average grade (i.e. ash percent, sulphur content, calorific value, etc.) of the coal in-situ. See, for example, Sabourin (1975), Woods (1976, 1979), Pauncz and Nixon (1979) and Armstrong (1980). These studies show that the established techniques of linear geostatistics can be applied successfully to coal deposits. The study by Woods is particularly interesting because he had access to the actual production figures as well as the initial sample data from the no 2 seam in the Greenside Colliery owned by the Anglo-American Corporation. He showed that the estimates obtained by kriging were consistently closer to the actual production figures than those given by three other estimation methods. This confirms the superiority of kriging as a method of estimating block values for coal. Another advantage of geostatistics is that it can be used to determine the optimal spacing between drill holes. An example of this is given by Armstrong for the coking coal deposit in the Bowen Basin, Australia.

Jan 1, 1981

By S. J. Schatzel

Longwall coal mine operators in the US are required to ventilate multi-panel longwall districts but may have little or no knowledge about what happens to the ventilation air between the inlet evaluation points (IEPs), bleeder evaluation points (BEPs), and bleeder fans. The effectiveness of bleeder performance can directly influence the ability of a ventilation system to remove and dilute coal bed methane emissions. Consequently, the performance of coal mine bleeders is an important aspect of underground worker safety. U.S. coal mining stakeholders have acknowledged their belief that the T- junction split at the longwall face tailgate corner is very important in controlling the distribution of ventilation air. The percentage of air directed inby towards the bleeders and bleeder fan and outby to the submains is often not well-defined and can vary over the life of a longwall panel. To obtain direct measurements of bleeder performance, a tracer gas, sulfur hexafluoride (SF6), was released into the intake air stream along the panline of active longwall panels and in the bleeder/gob ventilation air inlets of an inactive panel. Tracer gas sampling was conducted underground using tube bundles attached to permissible vacuum pumps in the gateroads, former gateroads, and bleeders. Surface tracer gas monitoring was also conducted from operating gob boreholes and from bleeder fans. Testing was performed on multiple longwall panels which included various phases of longwall development and variable path lengths of ventilation air transport to bleeder fan installations. The applied methodology defines and describes coal bed gas pathways, rates, and volumes of movement at the bleeder/gob interfaces, and indicates flow rates for air/gas mixtures within these gobs. These findings are reported for three stages of longwall extraction using direct field-based measurements. Changes in the T-junction ventilation air distribution over the life of a longwall panel and its variable effect on panel ventilation airflow are discussed. These findings will assess the effectiveness of commonly applied ventilation strategies for improving air distribution and ventilation controls to meet statutory requirements and to achieve the desired ventilation patterns through multiple phases of longwall panel extraction.

Jan 1, 2011

By J. Brune, P. J. Coleman, L. Martini

Research in the field of mining safety and health in the United States plays an important part in protecting the lives of miners. The National Institute for Occupational Safety and Health (NIOSH) Mining Program conducts surveillance, studies and developmental work aimed at improving the safety and health of miners. With recent reviews of the Mining Program by the National Academy of Sciences and the Mining Program response (NIOSH, 2008), the importance of setting goals, conducting high quality engineering and scientific research and evaluating the outputs, outcomes, relevance and impacts of these projects has been reemphasized. Surveillance of reported injuries is a first step in deciding on research directions and in designing specific projects. Groups of injuries often share features and attributes that suggest common causes and may respond to similar preventive efforts. Identifying groups of injuries also serves to prioritize intervention efforts. The Mine Safety and Health Administration (MSHA) Accident and Injury database (MSHA, 2008) provides individual case reports of mining injuries, illnesses and certain no-injury accidents (events such as roof falls that stop mine production or miners’ activities for more than one hour). This database is an indispensable resource for researchers and stakeholders needing information on the statistics of these events. From an epidemiological perspective, research projects target groups of miners at risk due to specific patterns of work, equipment, mine settings and the management of safety and health in their mines. Incidence rates are provided by the MSHA data for selected variables, such as surface/underground location, standard industrial classification and state. While incidence rates are the preferred measure for all variables, denominators are not typically available; for example, to more clearly understand the data about injury by occupational type, it would be necessary to conduct demographic surveys. A current survey of the demographics of the mining industry should be complete by 2010, which will allow incidence rates to be developed for a number of variables such as age, occupation and experience. This survey will provide the first update of its kind since the first survey was conducted in 1985. This report describes an alternative method of analyzing and presenting MSHA data for the purpose of identifying high-cost, high-severity injuries and illnesses. Researchers at the NIOSH Spokane Research Laboratory (SRL) developed programs to find the top five most frequent accident classes, natures of injury, types of accidents and other selected variables from the MSHA database. Studying these variables gives a cross-sectional snapshot of the most frequent groups of injuries within a commodity, regional group or time period, and allows researchers to quickly understand developing patterns for new research projects. The primary benefit of this approach is to

Jan 1, 2009

By Glenn M. Boyce, Timothy R. Coss

Microtunneling first appeared with some regularity in the United States in 1987. Until then, only Japan and Germany utilized this method of construction. Its high costs initially limited its application to special situations. The last ten years have seen the use of new pipe materials, new machines, new cutterheads, new techniques, and an average growth of30 percent each year. This paper documents the growth and changes that have occurred with microtunneling. Based on current industry practices and advances from abroad, this paper postulates what the next ten years may hold.

Jan 1, 1997

By M. A. Barclay, D. Samson, A. M. Esteves

Several companies have adopted policies and standards aimed explicitly at increasing ‘local procurement’, recognising that local economic participation has benefits for companies and communities alike. From a corporate perspective, local economic participation is seen as one means of maintaining a social license to operate, as well as ensuring reliability of supply by having a supplier located nearby. From a community perspective, the participation of local businesses in the resource project is a means by which the benefits of resource development can flow into their communities. This paper is based on the research undertaken to produce a good practice guide for the mining, oil and gas sector. Our research revealed that the extent to which the local community will actually benefit from local procurement initiatives is dependent on the capacity of the community to supply goods and services to the project and, even more importantly, on its ability to adapt to the inevitable changes that accompany large-scale resource development. We provide guidance on adapting impact assessment tools to guide planning of procurement interventions.

Jan 1, 2011

By M. Adnan Goksel

A blast furnace test of approximately 5,000 tons of PelleTech Corporation (PTC) cold bond pellets was successfully run at Kaiser Steel Corporation (Kaiser) Steel Manufacturing Division at Fontana, California. The pellets were produced from mill scale, BOF dust and blast furnace flue dust. A 15 day base period, during which time the metallic burden was 2/3 heat indurated pellets and 1/3 sinter, preceeded the test. During the test period the metallic bur- den was 10% cold bond pellets, 56.7% heat indurated pellets and 33.3% sinter. A 15 day post test base period followed during which the PTC pellets were replaced by conventional pellets. The pellets were produced in the 3.C Semi-works Facility located on Kaiser property. The facility incorporates the Michigan Technological University Hydro-Thermal Agglomerating Process.

Jan 1, 1979

By David A. Fawcett

An auxiliary cross-pit mining system, working in tandem with the prime excavator, is evaluated technically, operationally and economically for application in the selective removal and replacement of soils and unconsolidated ovezburden. Previous studies on cross-pit technology and applications of this technology are briefly reviewed. Stratigraphy plus pit, operating and economic parameters are assumed and applied in the evaluation and comparison of a base case dragline system with two alternatives - a dragline/scraper-dozer combination and a drag- line/cross-pit system combination. The economics of the proposed cross-pit system favour it as a viable alternative to conventional systems.

Jan 1, 1981

By Howard S. Avery

The wear resistance of an alloy in heavy mill liner sections may be quite different from that of the same alloy in small balls and other light sections. This fact was established by means of a well standardized laboratory test that was validated for ball mill service. The salient properties of mill liner alloys, including austenitic manganese steels, medium alloy hardenable steels, and abrasion resistance cast irons are described, critically compared, and quantitatively ranked in terms of mill liner service. Where they are tough enough the high-chromium and other martensitic cast irons (e.g. Ni-Hard) promise maximum economy, but their section sensitivity is a limitation. To overcome this an extensive research program studied over a hundred experimental alloys, ranking them for heavy section abrasion resistance by means of the laboratory test. Computer analysis of the results provided a parabolic formula in terms of composition, the apexes of the parabolas providing optimum wear resistance. From the extensive family of parabolas one apex was selected for intensive study in experimental liners, pilot plant production, development of quality controls, and finally full scale production. This is a 19% chromium iron critically alloyed with nickel and molybdenum and hardened by heat treatment. It has excellent resistance to various types of abrasion, but its chief advantage is in heavy mill liner sections, where it has about 25% better abrasion resistance than the best of the quality controlled chilled Ni-Hards. It is also tougher. After production problems were solved, a number of ball and rod mill tests were arranged on a guaranteed performance basis. Two of these, representing about 138,000 pounds of mill liner castings, have recently confirmed in service the superiority that was predicted by the laboratory tests.

Jan 1, 1969

By Felicia F. Peng

The plant data were collected from three streams around a dense medium drum for coarse coal cleaning operated at various volumetric ratio of medium-to-feed. The effect of the volumetric ratio of medium-to-feed (MF) and particle sizes on the performance criteria, g50 and Ep, of the dense medium drum. These measured data were adjusted and calculated for the yields and balanced relative density distributions by mass balanced method based on the statistic principle. These balanced data were then used to formulate the mathematical models of the separation distribution curves for the various feed size intervals. The correlation equations for the g50 and Ep as the function of inverse of the feed size, and MF and total throughput were established. A numerical algorithm utilizing the Secant method, based on the root searching principle, was developed for yield optimization and simulation of dense medium drum separation to improve the separation efficiency and hence the product yield. The relationships between the direct ash content and relative density of the particles in feed and the products were established and incorporated into the numerical algorithm for predicting the product quality.

Jan 1, 1996

By Walter N. Campbell

The Simon Silver Mine is located near Mina, Nevada, approximately 50 miles northwest of Tonopah and 40 miles east of Hawthorne. It is an old property which was last worked in 1932 and closed operations due to problems arising from low metal prices. Federal Resources Corp. acquired the property in 1963 and undertook a completely new development program since the old surface plant and underground workings were beyond feasible repair. The deposit of silver, lead, zinc and copper is predominantly replacement of limestone. In the summer of 1964, a new surface plant was constructed and on December 2, 1964, sinking of a three compartment vertical shaft started and was completed to a depth of 1088 feet in April of 1965. Following the sinking program an 850 foot crosscut was driven to intersect the mineral zone on the 1000 level after which drifting, crosscutting and raising totaling some additional 4280 feet has been completed along with considerable diamond drilling and long holing into the walls. To date, two ore bodies have been encountered and test stoping operations are underway together with development of the 800 level for servicing, ventilation and access. The present development of ore is directed towards substantiating sufficient reserves to warrant the construction of a flotation mill.

Jan 1, 1967

By Gerald A. Zicg

The Sheep Creek project area lies between 15 and 20 miles north of White Sulphur Springs in west central Montana, on the southern flanks of the Little Belt Mountains. The Sheep Creek project is a joint venture in which Cominco American Resources, Inc., has a 50% operating interest and BHP-Utah International, Inc., has a 50% participatory interest. The property consists of over 40,000 acres of leased fee land and lode claims. Modern exploration of the Sheep Creek area began in 1973 and 1974, when Homestake Mining Co. examined the extensive Sheep Creek gossans with soil sampling, trenching, and drilling. Cominco American Inc. began exploration in the area in 1976. Between 1978 and 1985, Anaconda Copper Co., Exxon Minerals Co., and Freeport also conducted exploration programs in the area. In 1985, Cominco completed consolidation of the district, gained BHP-Utah International, Inc., as a joint venture partner, and the joint venture drilled the first significant copper mineralization on the property. Of six bodies of copper mineralization so far located, the best defined are an upper copper zone, which includes a probable resource of 4.5 million metric tonnes grading 2.5% Cu and 0.1 % Co, and a lower copper zone which includes a possible resource of 4.5 million metric tonnes grading 4% Cu. Exploration drilling of the property is in progress.

Jan 1, 1991

By R. H. King

The Deserado Mine of Western Fuels- Utah Inc. installed a micro-computer based mine wide monitoring and control system for mine environment, beltway fire protection, belt operating parameters, and equipment power utilization. The Colorado School of Mines was funded by the U.S. Bureau of Mines to document, evaluate, and report on the system design, procurement, installation, tests, and operation. This paper results from that project. The paper compares planned activities such as installation and start up, procurement contract specifications and system layout with actual performance to develop recommendations for future installations by mine operators.

Jan 1, 1987

By M. Soderstrom

In a solvent extraction (SX) plant, stage efficiency calculations are used to determine mixer efficiency. With modern extractants and mixing equipment, it is generally taken for granted that stage efficiencies will be above 95%, but this is not always the case. Dependant on mixer/solution conditions, stage efficiencies can occasionally be low, therefore leading to higher reagent usage. Proper methods to identify when stage efficiency performance is below expectations, and ways to identify if it is an equipment or chemical issue are valuable tools for a plant metallurgist. With these tools and skills an on-site metallurgist can more quickly return their SX plant to proper operation. This paper will discuss methods for analyzing stage efficiency, evaluating factors that may affect stage efficiency, and evaluating the impact of stage efficiency on the overall operation.

Jan 1, 2010