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By P. J. Remington

Field measurements utilizing a seat pad accelerometer were made on 25 underground coal mining machines in order to quantify the vibration levels experienced by the operators. Those data were combined with information on the statistics of the operating times of those machines in order to compare the operator's vibration exposure to the criteria in ISO 2631, "A Guide for the Evaluation of Human Exposure to Whole Body vibration." The comparison showed that about 30% to 40" of all underground coal mining machine operators can be expected to be exposed to vibration exceeding the fatigue decreased proficiency criterion, whereas only 10 to 15% would be expected to experience vibration exceeding the exposure limit. The primary sources of the exposure are shuttle cars and possibly scoop trams. Detailed exposure statistics are presented and the implications of the results are discussed.

Jan 1, 1983

Structurally- controlled deep leaching processes have removed vast quantities of carbonate from a substantial portion of the "silica-dolomite" enclosing the 500 copper orebody. Mine drainage subsequently allowed free access of air to the porous environment created and oxidation of sulphides commenced. During the mIne development stage the exothermic and temperature-dependent nature of these hydrolysis reactions resulted in a slow general elevation of ground temperatures. and levels of 90 - lOO°C were attained in restricted moist sulphide-rich areas.With the advent of production and extensive use of explosives, the oxidation processes were locally raised to new levels of activity. Direct interaction of explosives and sulphides in favourable conditions caused temperature rises to above 260 C. Above this point the dry oxidation of sulphides in air was initiated and rapid escalation to the vicinity of 800 C has been known to occur in isolated cases.Ground reactivity is a function of the complex interrelationship of several controlling factors and no simple index exists.Control techniques are presently aimed at prevention of temperature rises in the range 100 -260 C. Inhibition of the rapid dry oxidation processes above 260 C is difllcult and current efforts have met with only partial success.

Jan 1, 1968

By R. Tessier, C. R. Larsen

"INTRODUCTIONOn November 10, 1982 Nor and a Inc signed an agreement with Golden Sceptre Resource Ltd. and Goliath Gold Mines Ltd. to construct a mine and milling facility.The Golden Giant mine is located in the Marathon area of north - western Ontario, immediately north of Highway 17 and about- 3.5 km west of Highway 614.With the exception of selected unit processes, the mill was designed for a nominal throughput of 2500 tonnes per day with early operating data to be used to identify sections requiring possible expansion to achieve an ultimate throughput of 3000 tonnes per day.Commissioning of the highly instrumented milling complex which includes crushing, grinding, cyanidation, and carbon in pulp processes commenced in February 1985. After water testing various sub-circuits from grinding through tailings, waste ore was introduced to ensure proper mechanical and electrical operation of process equipment.The first ore was milled as a mixture with waste on March 4, 1985. The first gold bullion was poured April 6, 1985.Initially, ore was only available from mine development at a rate of 700 t/d, which was milled at a minimum rate of 1200 t/d. While regular weekly shut downs of two to three days was useful for mechanical maintenance, changes, and modifications, process tuning was more difficult due to the non-steady operation. As increased quantities of ore became available, regular weekly shutdowns tapered off and process operation improved accordingly. For testing purposes and as ore was available, mill throughput was increased regularly to 2300 t/d and for very short periods of time to nearly 3000 t/d.No major design or operating problem has been encountered to date. The following is a brief description of the milling process and various operating highlights. Process flowsheets are shown in Figures 1 through 6."

Jan 1, 1986

By SUMNER S. SMITH

Mine inspection in Alaska by the Federal mine inspector was somewhat handicapped during 1915,the inspector having to spend a large part of the summer and fall in examining the Matanuska coal field in connection with the designation of the Government reservations and the leasing units in that field. However, in addition to>this work, the mines in southeastern and southwestern Alaska were inspected by both Federal and Territorial inspectors, a considerable number of men near the Federal inspector's officeat Juneau were trained in first aid to the injured and in the use of mine rescue apparatus, the mines of the interior and of Seward Peninsula were inspected by the Territorial inspector, and a suit was brought in the name of the Territorial inspector for the nonreporting of serious accidents under the Territorial inspection law. The work of the Federal inspector was handicapped also by a lack of field assistants. This condition is likely to be serious, as preparations have been made for opening the Matanuska, Bering River, and Nenana coal fields, and a number of permits granting the free use of 10-acre tracts in other fields throughout the Territory have been issued. The need of a comprehensive inspection law and experienced engineers to safeguard the opening of coal mines by operators who are not familiar with coal mining and are using inexperienced help is obvious.

Jan 1, 1917

By Harold E. Marr

A simple algorithm is presented for processing digitized X-ray spectra obtained with a Si(Li) or Ge(Li) semiconductor detector coupled to a multi- channel analyzer. The simplified least-squares procedure is used to smooth out the statistical fluctuations in the spectrum by repeatedly fitting a quad- ratic equation to a predetermined number of channels and performing a traveling smooth across the spectrum. A logarithmic transform is applied to the raw data to minimize the distortion of the gaussian-shaped peak profiles. The efficacy of the technique is evaluated by observing the distortion of several gaussian-shaped peaks that have been subjected to the smoothing operation. The locations of maximums and minimums in the spectrum are predicted in the process as well as the values of the peak heights. The convolution integers from a least-squares fit of a quadratic equation are calculated as part of a FORTRAN subroutine. The building-block approach to computer programing in a small laboratory is discussed.

Jan 1, 1972

By J. C. Watts

Monitoring and control of conventional industrial wet grinding circuits is conceptually straightforward. However, since production objectives and operating constraints can vary widely from plant to plant, there is probably no single overall grinding circuit control strategy which is "best" in all cases; in-variably some compromise is necessary between performance desired under ideal conditions and performance achievable in practice. The recent advent of relatively low cost, reliable, high speed small computer systems is revolutionizing daily operations in increasing numbers of metallurgical processing plants. Of special power and capability is a hierarchical computer network like that currently in use at the Pinto Valley Operations of the Cities Service Company. Several satellite processors for key plant areas communicate with a master computer operating under a powerful multitasking real-time operating system. Hardware and software structure is such that downtime on one of the processors -including the master -does not have a major impact on overall system operation. Admittedly, the powerful, core efficient table driven satellite software, which handles process/computer communication, calculation of nonmeasured process variables, and basic Direct Digital Control functions, is difficult to modify. However, important high level process monitoring, report preparation, graphic display, and supervisory control functions -including economic optimization -can be implemented by project engineers at the plant site. Thus, for example, new control strategies can be quickly examined and rapidly evaluated. Such computer monitoring capability also permits use of short duration process pulse tests for approximate dynamic modeling and rapid calculation of controller tuning constants for single loop dominant systems. Following a brief back-ground discussion of the Pinto Valley Project, we present some of the more interesting results and conclusions of our work over the past year.

Jan 1, 1978

By F. Bonnet, J. Lehmann, H. Gaye

A review of thermodynamic information and models of slags, including associated software when available, is presented. The pertinence and accuracy of these models is discussed by comparison of their predictions for various slag thermodynamic properties with the available experimental data. Practical industrial applications will be illustrated by a literature review of the dephosphorization process of ferromanganese alloys and by the description of Ti behavior during silico-manganese alloys production. This latter example will show how the thermodynamic models have been used to propose a flotation treatment at low temperature to enhance TiC removal.

Jan 1, 2004

By P. H. Morris

The exponential delta profile equation matches the profiles of a wide range of coal and metalliferous subaerial tailings deltas well, but the original model implies unrepresentatively low solids concentrations. A revision, based on analysis of the governing equations of mobile bed flows with high concentration values, has shown that for exponential delta profiles to form there must be quasi-steady, slowly varying flow and slow deposition as well as tailings with a log-uniform sorting-parameter distribution. Deposition on tailings deltas is slow and the flow in many natural streams and, by analogy, tailings deltas is quasi-steady and slowly varying; the assumption of such flow is justified by the strong congruence of the revised model and the available data. The predictions of the theoretical model are essentially unchanged but concentration and flow Froude number are now not explicitly limited

Jun 19, 1905

PRODUCTION of cesium, cesium salts, and rubidium salts in the United States declined somewhat from 1961 levels; rubidium production was virtually unchanged. Imports of pollucite declined because consumption was supplied partially out of inventory. Domestic Production.-About 50 tons of pollucite was reported mined at the Tin Mountain mine in the Black Hills of South Dakota. The Dow Chemical Co., Midland, Mich., MSA Research Corp., Callery, Pa., and Penn Rare Metals, Inc., Revere, Pa., produced a total of 159 pounds of cesium. Rubidium production remained essentially the same as in 1961. Shipments of the two metals by these companies and by American Potash & Chemical Corp., Trona, Calif., totaled 279 pounds. Production of cesium and rubidium salts by American Potash & Chemical Corp., Penn Rare Metals, Inc., and Rocky Mountain Research, Inc., Denver, Colo., declined substantially during 1962.

Jan 1, 1963

By C. Nexhip, S. Sun

Critical to understanding and controlling phase mixing and separation in metallurgical processes, is the development of reliable experimental techniques to measure interfacial properties of melt systems. A series of experiments has been carried out to determine the effect of oxygen potential on the surface tension of liquid copper. Using an electromagnetic levitation method, a surface tension-oxygen chemical potential adsorption isotherm was produced for the Cu-O system at T 1400 K. The surface tension results show good agreement with the literature values e.g. within 3 per cent for pure copper. The Belton `ideal' adsorption isotherm was applied, and the following equation derived to best fit the experimental data ? =1251-77.5 1n41+ (2.79x105 . pO1/2)](mN.m Using this equation, the surface tension of copper was calculated/predicted as a function of oxygen potential at 1400 K, and showed excellent agreement with the experimental values. This confirmed that the adsorption behaviour of oxygen in liquid copper is ideal. The saturation coverage of oxygen on the surface of liquid copper was determined to be T0 = 6.65 µmoles.m,-2 corresponding to an area per adsorbed oxygen atom of ao ? 25 Å2. These values agree well with those cited in the literature, and our experimental data cover a very wide range of oxygen potential (10-5 to 10-17 atm). Keywords: levitation melting, surface tension, Cu-O alloys, oxygen potential, adsorption isotherm, surface coverage.

Jan 1, 2004

By A. C. Smith

The U.S. Bureau of Mines evaluated the effectiveness of automatic water sprinkler systems on the suppression of incipient and propagating conveyor belt fires under ventilated conditions. Large-scale experiments were performed at airflows ranging from 1.1 to 4.6 m/s. In incipient fire experiments with 100°C, standard-response sprinklers installed above and between the belts, the sprinklers activated later, the peak heat release rates were larger, and more belting was consumed at the higher airflow. In similar experiments with 74 °C, fast-response sprinklers, the sprinklers activated at the same heat release rate for both high and low airflows, but the peak heat release rate and amount of belting consumed was slightly higher at the lower airflow. In incipient fire experiments with sprinklers located only above the top belt, the heat release rate and amount of belting consumed was larger at the higher airflow. The propagating fire experiments showed that sprinklers located above and between the belts were effective in stopping flame propagation. Peak heat release rates and amount of belting consumed were larger at the higher airflows for both the 74 °C, fast-response and 100 °C, standard-response sprinklers. The sprinklers were equally effective at each airflow.

Jan 1, 2010

Recent advances in GPS, machine guidance technology and telemetry allow an unprecedented level of control of surface mining operations. GPS technology can now locate the bucket of a shovel or the blade of a dozer within 50mm (2 inches).Some of the outcomes possible are: precise selective mining – even when the ore is visually indistinguishable from waste: tracking grade and tonnage of every ore parcel through the mine: real time productivity monitoring: detailed post accident safety analysis: tracking the movements of every piece of equipment. This paper will consider the contribution that GPS based machine control systems can make to ensuring that surface mining projects deliver the outcomes promised in the feasibility studies. Case studies of installations are presented.

Jan 1, 2004

By Ronald W. Schaefer

This report describes operations at the Rosiclare Fluorspar Works of the Aluminum Co. of America at Rosiclare, Hardin County, Ill. The works include the Fairview mine, the fluorspar mill, and related facilities. The publication covers exploration, development, mining and milling practices, mine-drainage problems, and other activities and is presented as part of the Bureau of Mines series of publications on mining and milling practices in various parts of the United States. The Rosiclare fluorspar area, for its size, has been the largest producer of high-grade fluorspar in the United States and probably in the world. The vein system in this area is over 5 miles long and 1/2 mile wide, and ore has been found as deep as 900 ft.

Jan 1, 1961

By W. H. Boyer, J. W. Gabelman

The concept of metal zoning has long been recognized (Spurr, 1907, 1923; Emmons, 1924, 1926; Lindgren, 1933; Rateman, 1950), although it has been considered indistinct for most epithermal districts. The geometric relation of barren zones of hydrother-mally altered rock to ore deposits was emphasized in the work of Lovering (1941, 1949, 1950), Sales and Meyer (1948, 1949, 19501, Burbank (1941, 1950), Schwartz (1939, 1950), and Kerr (1947). Lovering (op. cit.) and Sales and Meyer (op. cit.) emphasized the consistent presence of barren alteration envelopes enclosing individual ore bodies, particularly of the vein type. Schwartz (1950) noted a difference between the distribution of alteration zones described by Lovering and by Sales and Meyer, as compared with those associated with the porphyry copper deposits of the Southwest. The disseminated deposits of the Southwest usually occur within large bodies of altered rock whereas most veins do not. In the following discussion the mineralization process is conceived of consisting of two distinct phases: pre-ore nonmetallic alteration and metallization. In the present investigation the position, size, and shape of all known hydro thermally altered areas and the position, size, and metal type of all known ore deposits were plotted on base maps of southwestern and west-central Colorado (Figure 1). The maps indicate a generally consistent geometric relation between altered and metallized areas. The addition of alteration to the pattern of metal deposits establishes a temperature zoning pattern of much greater clarity than that formed by the epithermal metal deposits alone, and allows a more precise definition of mineral belts. The center of strongest mineralization is indicated to be the area of greatest barren alteration, and metal deposits are grouped about it both under structural control and crudely in response to temperature zoning. The combination of an area of strong alteration and associated marginal clusters of metal deposits is defined as a mineral district. The strong similarity in individual deposits, in groups of different types of deposits, and in the alteration-metallization relation in districts throughout the region implies that a single metallogenic province is represented in southwestern and west-central Colorado. The occurrence of deposits in Tertiary voi-canics indicates a late Tertiary metallogenic epoci., although an early Tertiary epoch is known locally as at Ouray. Patterns formed by mineral districts can be

Jan 1, 1961

By G. Danko, R. Tiwari, J. Knowles

Many excavation and loading tasks require equipment operators to simultaneously coordinate the motion of multiple machine links, in order to achieve complex tool trajectories. Efficiency, ore selectivity, and machine wear, are all affected by the skill level and attentiveness of the operator. A software-based kinematics reconfiguration system designed to assist operators with various tasks has been implemented on a small experimental excavator using our new differential control architecture. Kinematics transformation and feedback control algorithms are being developed and tested using computer simulation, and the results implemented on the experimental excavator. Several task-specific kinematics transformations, including a virtual revolute-to-Cartesian machine reconfiguration and computer-assisted bucket steering and stabilization have been successfully tested. Progress, challenges, results, expected benefits, and planned work are described.

Jan 1, 2006

By E. A. van Wyk, M. R. de Villiers

"Mining companies strive to increase and maintain production, while simultaneously remaining competitive in the global economy. Furthermore, they must ensure workers’ safety and maintain good safety records. The use of virtual reality (VR) facilitates the development of tools and systems for various purposes that can improve knowledge and understanding of the work environment. VR is a rapidly growing technology that uses the ever-increasing power of computing to simulate real-world and imaginary environments and situations with a high degree of realism and interaction. The availability of 3D modelling tools and simulation programming engines that work effectively with a mid-range desktop PC and standard 3D graphics card, make VR technology viable and attractive for mainstream training applications. The design, development, and implementation of interactive VR training systems is proposed as an innovative approach to augment safety training. However, in order to assess the impact of such VR training systems it is of particular importance to determine the effectiveness of the design of such systems. This article proposes an evaluation framework for this vital purpose. This framework comprises criteria to assess VR training systems, specifically relating to usability, instructional design, VR systems design, and mining industry context-specific aspects. Although the framework was developed as an evaluation tool to assess effectiveness of the design of such systems, it can equally well be used as a set of design principles to inform the design of VR training systems for mining. IntroductionMining in South Africa has been the main driving force behind the history and development of Africa’s richest and most advanced economy (Coka, 2012). The South African mining industry is frequently criticised for its poor safety record and high fatality rate (Stoddard and Skweyiya, 2016). Inadequate or insufficient training is often cited as a root cause of accidents (Van Wyk and De Villiers, 2009; Tichon and Burgess-Limerick, 2011). Virtual reality (VR) is a rapidly growing technology that utilizes the ever-increasing power of computing to simulate real-world and imaginary environments and situations with a high degree of realism and interaction (Webber-Youngman and Van Wyk, 2013). VR is currently being used or investigated as a training solution in a variety of industries. VR technology has developed rapidly and costs have fallen to levels where it can now be considered for mainstream training applications. The availability of 3D modelling tools and simulation programming engines that work effectively with a mid-range desktop PC and a standard 3D graphics card, make VR even more attractive to mine training centres (Van Wyk and De Villiers, 2009)."

May 1, 2019

By D Cliff

"Recent underground coal mine incidents have again raised the issue of: under what circumstanceis it safe for personnel to re-enter the mine? Mine rescue guidelines make recommendations aboutthe limits in terms of the circumstances, lives at risk, no lives at risk and training exercises. Theseare based upon percentages of the upper and lower explosive limits. Many factors infl uencesett ing limits for safe re-entry. These include: the representativeness of the sampling location(s),the rapidity of gett ing an underground sample analysed and the rate of change of the atmospherebeing monitored. Value judgements based upon these parameters will then infl uence the sett ing ofa trigger point based upon per cent explosibility. This raises the question of how the percentage ofthe lower or upper explosive limit is established. It is easy to defi ne this when the sampling pointdata sit on the fresh air limit line. However - what value is used when the sample sits somewherein the body of an explosibility diagram? This paper explores the various options and illustratesvarious pitfalls and problems that are faced in making such a determination. These include howthe data are represented and the assumed knowledge of those doing the interpretation."

Jun 1, 2012

By L Eriksson, D Penn, J Appelgren

Atlas Copco, a leading supplier of equipment and services to the mining and construction industries, is consistently pursuing its strategy to offer the most productive and economical solutions by continuously offering new innovative products. These are, in most cases, developed and tested in close cooperation with demanding end users before being officially launched on the international market. The demands for higher productivity and improved overall economy have resulted in systems for automation of the drilling cycle and also tools for integrating the drilling equipment to the production control system used by the customer. In terms of improving the blasted material quality, the company has placed emphasis on accuracy in the drilling process and documenting what has been drilled. By applying state of the art technology to the common automation platform, developed for the surface drilling market, major steps in improving overall drilling productivity and blasting performance have been achieved. This paper will give some examples derived from the latest development of solutions for the companyÆs surface drilling products.CITATION:Appelgren, J, Eriksson, E and Penn, D, 2012. Rotary drilling automation increasing operator productivity and drilling quality, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 13-18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

Significantly increase the amount of fresh air that sweeps the face in front of a continuous mining ma-chine, in order to prevent methane gas buildup. Approach Water sprays are mounted along the sides of a continuous miner and behind the cutter head to help push ventilating air along the required path, and prevent its short circuiting. How It Works A continuous miner is fitted with two sets of water sprays, one of which is used at a time. The set of sprays shown in the diagram, helps move the ventilating air forward along the left side of the miner and across the cutter drum from left to right. That air is then drawn into the exhaust air passageway located along

Jan 1, 1978

By M Wieloch, D Wimpenny, M Chappell

Fibre-reinforced geopolymer concrete (FRGC) contains no Portland cement or steel reinforcement, but instead uses synthetic fibre reinforcement and a geopolymer binder. The use of geopolymer binder in lieu of Portland cement reduces the concrete’s embedded energy (CO2 emissions) whilst the use of synthetic fibres eliminates the issue of reinforcement corrosion, thus enhancing the overall long-term durability of concrete. This paper presents the development of FRGC during a three-year project funded by the Victorian Science Agenda and a consortium of five organisations. The work involved laboratory and field trials and the production of prototype tunnel segments that have been subject to durability and fire testing.FRGC has exceeded the performance of the Portland cement-based control mix in terms of flexural strength, chloride diffusion, water sorptivity and drying shrinkage. Furthermore, the FRGC segments subjected to a simulated hydrocarbon fire test did not exhibit explosive spalling; however, the creep of FRGC was approximately three times that of the steel fibre-reinforced Portland cement-based control mix. The compressive strength and tensile splitting strength of the FRGC were also lower than the control mix. These differences need to be allowed for in the design using FRGC.Prototype bolted tunnel segments of up to 0.8?t mass have been produced from FRGC using standard production techniques and ambient curing. These were successfully produced within a 24-hour production cycle. Cut sections through the segments showed good compaction and even distribution of fibres. The estimated carbon footprint of tunnel segments produced using FRGC is approximately 70 per cent less than that of Portland cement-based segments containing 25 per cent fly ash and steel reinforcement.The results to date indicate that FRGC has the potential to produce a new generation of tunnel segments and, in general, precast concrete products with increased durability and substantially reduced carbon emissions compared to the Portland cement-based concrete with steel reinforcement.A summary of further research carried out by CH2M HILL into a complete elimination of ferrous inserts from segmental concrete tunnel lining is also summarised in this paper. The use of non-ferrous connectors for radial joints in combination with the FRGC technology in the manufacture of tunnel segments will effectively lead to development of a new generation of segmental tunnel lining systems.CITATION:Wimpenny, D, Chappell, M and Wieloch, M, 2014. Fibre-reinforced geopolymer concrete – an innovative material for tunnel segments, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 345–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014