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By R J. In, C Moore, P J. Moffitt, T Hansen

Telfer Gold Mine combines a world-class gold and copper resource and longevity of operation as a major gold and copper producer. Telfer Gold Mine has undergone a series of transformations since mining commenced as a high-grade narrow-vein oxide open pit operation in 1977. In 1986, the open pit operation converted from a narrow-vein, high-grade operation, to a low-grade high-volume oxide mining operation utilising dump leach processing technology. Mechanised underground mining of the high-grade narrow-veins commenced in 1990. Total recovered gold production between 1977 to 1999 has totalled 5.7 million ounces. The Telfer Extension Project consists of two pre-feasibility studies, the Surface Extension Project (SEP) and the I-Series Project (ISP). The combined studies represent one of the more significant resource evaluations undertaken in the gold industry in recent times. Geological activities for the SEP pre-feasibility study have included the drill definition of a large low-grade resource within an area of 25 km2 . The surface drilling program has completed 15 000 metres of HQ3 diamond drilling and over 30 000 metres of RC between last quarter of 1998 and late-1999. The ISP pre-feasibility study is currently evaluating the resource potential of both a high-grade low-volume and a lower grade bulk mining scenario, 800 m to 1200 m below the surface of Main Dome. 15 000 metres of underground diamond drilling have been completed between last quarter of 1998 and August 1999 as part of this study. Systems and cultures have been developed to maximise safety, monitor the quality assurance/quality control (QA/QC) on all aspects of the operation, and minimise impact on the environment. All data are stored in database systems, specifically designed for Telfer operations. 3D geostatistical resource estimation using ordinary kriging has been carried out for over 220 geological domains within the 25 km3 of mineralised system. Non-linear geostatistical techniques are being investigated as part of the pre-feasibility study.

Jan 1, 2000

By R. E. Allen

THERE was once a time when a practical oil man would appraise or buy a producing property on the basis of from $200 to $500 per barrel of average daily settled production. Curtailment-has, for the present at least, caused a virtual abandonment of the "barrel -of settled production" as a yardstick of, oil property value and in its place has come the "barrel of allowable production," which, although an artificial thing, is nevertheless now the principal factor governing the rate of ?pay out? or investment return. The potential production of a well, settled or otherwise, is of less importance in determining the present worth of a well than is the rate at which it may be produced. Speaking only of true potential for the moment, it is obvious that of two similar wells having the same potential, the one having the highest rate of allowable production would be worth proportionately more than the one of lesser allowable. The discount factor for deferred return and risk can easily vary the present values of the two wells by as much as 20 per cent when allowable rates are not greatly different.

Jan 1, 1934

By Robert H. Merrill

A method of determining the strength of a mine roof layer in place is described in this report. The method was tested on a limestone roof layer 50 feet wide, 100 feet long, and 20 inches thick. In place measurements were accomplished by introducing air under pressure into a separation between the layer and the overlying roof, and as pressure was increased, the corresponding strain and deflection of the roof layer were measured until the roof failed. The ultimate strength of the roof agreed with the tensile strength of the roof rock (modulus of rupture) as determined in the laboratory; the modulus of elasticity as measured in place did not agree with the laboratory-determined values; the deflection and tensile strain in the layer in place showed good agreement with the theory of a body-loaded beam clamped at both ends. This procedure for determining the strength of a mine-roof layer is safer and less costly than successively widening a roof to failure. For example, it would have been necessary to mine the room to a width of 114 feet and a length of 228 feet to produce failure in this roof layer. The method is not necessarily limited to limestone; any thinly bedded rock type can be tested by this procedure when there is an open parting over the mined area.

Jan 1, 1958

By D. K. Marjaniemi

The U.S. Bureau of Mines inventoried and characterized mineral sites and production plants within 200 km of the border in both the U.S. and Mexico. Sources of information included the USBM Minerals Availability System, the USBM Automated Mineral Information System, the USGS Mineral Resources Data System, the Mine Safety and Health Administration Address/Employment File, and the literature. Three hundred seventy-eight major construction material and industrial mineral properties were identified and characterized in the U.S. and Mexican parts of the Borderlands. Sixty-six major metallic mineral properties were identified and characterized in the Mexican part of the Borderlands.

Jan 1, 1996

By Earl Oliver

SEVERAL notable papers, and free discussion on many controversial subjects, marked the various sessions of the Petroleum Division at the annual meeting. The Division first convened on Tuesday afternoon, Feb. 16, and wound up with a dinner and technical meeting on Thursday night. H. C. Fowler presided at the opening session, which was devoted to problems of engineering research and production engineering. Joseph Chalmers abstracted his paper on the flow of air and gas through porous media, in the preparation of which E. L Rawlins and D. B. Talia-ferro contributed. G. H. Fancher told how much he and his associates at Pennsylvania State College were interested in this field, and described the problems they had met in conducting test work. He made a plea for standardization of testing methods. Mr. Fowler then read an abstract of written discussion by Professor Barb, which was followed by discussion by Dr. Fancher and Mr. Chalmers of technical points in connection with the Chalmers' paper. H. H. Hill abstracted written discussion from Messrs. Wilde and Moore, of the Humble company. The second paper, by K. B. Nowels, on computing pressure drop in the pipe of flowing oil wells, was abstracted by the author. Messrs. Blair Smith, G. W. Coggeshall, and I. I. Gardescu participated in the discussion, and the chairman abstracted written discussion prepared by Mr. Rawlins. Most of this had to do with the viscosity of gas¬oil mixtures, on which subject Mr. Nowels said there was great need of accurate technical information.

Jan 1, 1932

By William Hustrulid

Pre-split blasting is a primary technique for creating slopes with a minimum amount of unwanted damage to the remaining rock mass. Rock slopes created in such a way have both safety-related and economic advantages. The applications extend from road cuts to rock quarries to large open pit mines. For example, as deep open pit mines approach the end of their operating lives, slope steepening is one option to be considered. To be able to safely achieve and maintain steepened final slopes, good blast design techniques must be available and applied together with close operational control. Pre-split blasting is an important element in this slope creation process.

Jan 1, 2007

By W Newton, J Price

This paper outlines the design, justification and performance of a gravity circuit upgrade at the Marvel Loch treatment plant. The design of the upgrade was simple but effective. The key components of the upgrade were the addition of a sluice and a second Knelson Concentrator. The sluice was installed as a pre-concentration step. The upgrade also included the purchase of a Mineral Cone to treat the increased quantity of gravity concentrate. The cost was low because of the use of mostly second-hand equipment. The result was that for a cost of $75 000 the gravity recovery doubled and the overall recovery increased by over one per cent. This paper shows that you do not need to spend millions of dollars to be innovative and successful.

Jan 1, 2000

By C. J. Bise

Virtual Reality (VR) is a concept in which the human experience of perceiving and interacting with a computer-modeled environment is achieved through the use of sensors and effectors. It is an advanced fonn of computer graphics where the images are generated based upon where the user looks and how the user moves. As personal-computer-based (PC-based) instruction gains acceptance as an innovative approach to providing safety training, VR offers the capability of providing a multisensory, rather than merely a multimedia, mode of presentation. VR has been effectively used by the military for training tank commanders and by hospitals for training surgeons. However, these applications have been limited to small numbers of highly skilled participants. The purpose of this paper is to examine VR's potential for enhancing the hazard awareness of larger numbers of individuals in a broad-based approach to mine safety training, such as new-miner, annual-refresher, and independent-contractor training.

Jan 1, 1996

By M Grigorescu, J H. Hodgkinson

The expansive, open cut iron-ore mines in Western Australia typically experience few days of rain per annum, often amounting to less than 250 mm. Unlike mines where rainfall is frequent, they may be less prepared for extreme rainfall events. Such events can cause erosion, flooding and sedimentation, drainage alteration, spoil and stock heaps wetting and effect slope stability. Such impacts may threaten personnel safety, infrastructure, and production. The CRATER (‘Climate Related Adaptation from Terrain Evaluation Results’) framework collates and interprets a mine’s pre-existing data and semi-quantitative information to assess vulnerability to, and ultimately plan to avoid or minimise, flood-related hazard to infrastructure, people, downtime, environment and revenue. Outputs assist decision makers to design investment strategies for minimising mining operations’ vulnerability to climate. Previously developed for smaller, wetter mines in Queensland’s coal region, the outputs provide a hot-spot map, fault tree analysis and an assessment of the mine’s capacity to adapt. The multicriteria evaluation (MCE) within a geographic information system (GIS), equally suits iron-ore mines’ siteconditions (elevation, slope, drainage, soil and vegetation) to identify critical inundation areas. Hotspot results provide target zones for in-depth fault-tree analysis that, in turn, present a range of sitespecific adaptation options. Rainfall-intensity and the number of rain days since the 1970s have increased over central and eastern parts of the Pilbara Region. While tropical cyclones may become less frequent, they are projected to increase in intensity. Although some parts of the Hamersley Ranges receive more than 500 mm per annum, rainfall in the Pilbara is generally very low. Therefore, experience of the impacts of extreme rainfall events in the constantly changing topography of Western Australia’s iron ore region may be sparse. Minimising potential effects can be proactively assisted using CRATER.

Nov 8, 2021

By Kai Hu, Xuewei Lv, Run Zhang

An oxygen sensor of zirconia-based solid electrolytes for in situ measurements of oxygen potential in high titanium slag was developed in the present study. With the facility, series of measurements of electromotive force were successfully conducted for different titanium slags at 1998 K under an argon atmosphere. Oxygen potential in the slag was calculated by the measured EMF and simultaneous readings of temperature using the modified Nernst equation. In addition, the relationship between slag compositions and the oxygen potential in the slag was explored in detail. It has been found that the oxygen potential increases with increasing FeO content in the slag and decreases with the increasing Ti2O3 content in the slag. The oxygen potential in the slag has been calculated thermodynamically and compared with the experimental measurements. The results showed that oxygen potential in the slag may be controlled by FeO/Fe equilibrium reaction.

Mar 1, 2018

By S. J. Ma

With the very effective depressant and collector developed by China Bluestar Lehigh Engineering Corp (hereinafter referred to as LEHIGH), satisfied results are obtained from laboratorial beneficiation tests on phosphate samples from Karatau, Republic of Kazakhstan by the direct flotation process. In this paper the effect of single factors on performance of flotation is studied and their applicable ranges are proposed. The final test results are described as follows: As the feed contains 23.20 % P2O5, and 3.96% MgO, a phosphate concentrate assaying 29.77%P2O5 and 1.54% MgO is produced, and the P2O5 recovery in concentrate is 88.28%. The beneficiation tests make it possible to simplify existing technology with fine grinding-desliming, followed by reverse & direct flotation system and consequently improve the concentrate grade and recovery for the future beneficiation plant

Jan 1, 2014

By T. A. Penzov

As a result of recent scientific and experimental studies new technical devices have been developed for monitoring and control the process of grinding. The description of microprocessor module MILLCONT 1 for control of the loading of the mill and microprocessor density control module DENSIMETER is given in the paper. The improved variant of the automatic system for ore grinding control in single-stage ball mill working in close cycle with a classifier with above mentioned technical means is shown in the paper. The loops for measuring and stabilization of the basic technological parameters (density of the ready pulp ? and fineness of grinding of the pulp ß) are described in the paper. The nowadays economic results in ore grinding process automation are given as well.

Jan 1, 2014

By Richard Franchot

DISCUSSION of a paper is sometimes more in-teresting in what has not been said than in what is said. In the present case the paper is mainly directed to certain thermo-dynamic relation-ships in the blast furnace. Careful reading of the dis-cussion fails to show a single use of the term, heat unit, or its equivalent. If we wish to know very-much about the furnace action it is necessary to count calories or B.t.u. Nothing much is. said about the availability of heat at high temperatures, although it will be generally admitted that in seeking underlying limiting factors in the furnace economy the hearth heat relations offer-the most promising clues. Those discussing the paper, with exceptions of course, apparently have failed to recognize an outstand-ing fact. It is a fact that the heat actually generated by the air oxygen in CO formation (including the blast heat) is in excess, after charging off radiation, etc., by from 70 to .90 per cent over the heat absorbed in melting the iron and slag and calcining the stone reduction by CO absorbing no heat. The fact stands out as plainly as does the fact that the furnace functions largely as a gas producer. The surplus heat is there. It is in the picture. Why not take a look at it, face the fact? That the surplus heat is necessitated by the hearth conditions admits of very little if any doubt. The furnace is really two separate pieces of apparatus: the hearth, doing certain work, and the superimposed shaft, doing certain other work. The combustion of fuel in the hearth, primarily serving the hearth pur-poses, generates much more heat and gas than the shaft requires, or can use, in smelting work. The result is surplus heat makes still more gas in the heat-absorbing reaction between CO, and coke; what is left of the surplus going to top heat. Here we have a simple yet adequate sketch of the furnace action. Having obtained a fairly comprehensive view of the existing heat relations of both hearth and shaft, the way to improvement seems quite plain. Either do more of the work above the hearth or put more heat into the hearth. Since there is already a great surplus of heat above the hearth, probably little needs to be done by way of increasing the proportion of the work done in the shaft. The shaft can, however, probably do much more work than it is now doing provided that a way, can be found to get more work, done in the hearth. The hearth heat is nicely balanced. Losses by radiation and water cooling and other losses are already taken care of. Any increase of hearth heat development could be utilized in taking care of increased smelting work. Aside from the possibility of increased blast heat, there is one sure way of putting more heat into the hearth, and this is to blow more air. And since the shaft already has more gas than it needs, the increased gas resulting from the greater blast volume can be withdrawn from the bosh after it has done its work in the hearth. Now an increase of burden will cool the shaft, cut down solution loss and thereby supply addi-tional coke in the hearth to burn with the additional air blown. The hearth heat per pound of coke charged will be proportionately increased. The balance between hearth and shaft will be better. Gruener's ideal will be more nearly attained, if not exceeded. Most inter-esting of all perhaps, the more the burden is increased, the more coke will reach the hearth and the more burden can be added. The effect is to be cumulative.

Jan 3, 1927

By John C. Machisak

THE INJURY data and experience at quarries and related plants of the United States are presented in this publication under the following general sections: (A) General injury experience: Tables 1 through 3: Contain current data on the number of injuries, injury-frequency rates, location, accident agency, degree of injury, and related employment data. (B) Injury experience at different kinds of quarries: Tables 4 and 5: Contain current, data on number of injuries, injury-frequency rates, locution, accident agency, degree of injury, and related employment data. (C) Injury experience by States: Tables 6 through 19: Contain current data on the number of injuries, injury-frequency rates, accident agency, degree of injury, and related employment data.

Jan 1, 1958

By Gorzalczynski. Stan

The recent trend in underground mine developments is ?big is better?. This is most certainly evident in the mine shaft and the conveyances that operate within its compartments. Today, there are several new installations requiring mine cages that can transport up to 170 passengers. The technology in mine hoisting is advancing to address a combination of higher capacity requirements, deeper hoisting depths and faster winding rates, however, some areas of the hoist plant have not changed for the past fifty years. The most notable of these areas is the shaft compartment guide string and the conveyance mounted safety arrest mechanism. The technology in use today for the protection of passengers in a shaft conveyance from a hoist rope severance incident, remains conceptually unchanged from Elisha Otis? design of 1850. The actual retardation components, the safety dogs, have taken on several forms since Elisha?s invention with the last major design change occurring in the late 1940?s. The arrest of a free falling shaft conveyance requires that the shaft guides withstand the energy imparted on them by the safety dogs. There are some very real limitations presented by the use of wood for this application. The new hoisting era will most certainly continue to demand larger capacity equipment but also, an increased awareness toward safety.

May 1, 2002

By Anna Carolina Cerqueira Neves

Synthetic fiber has been gradually replaced by natural fiber, such as lignocellulosic fiber. In comparison with synthetic fiber, natural fiber has shown economic and environmental advantages. The natural fiber presents interfacial characteristics with polymeric matrices that favor a high impact energy absorption by the composite structure. However, until now little has been evaluated about the hemp fiber incorporated in polymeric matrices. This study has the purpose of evaluate the impact resistance of this kind of epoxy matrix composite reinforced with different percentages of hemp fibers. The impact resistance has substantially increased the relative amount of hemp fiber incorporated as reinforcement in the composite. This performance was associated with the difficulty of rupture imposed by the fibers resulting from the interaction of hemp fiber / epoxy matrix that helps absorb the impact energy.

Aug 16, 2017

By B K. Hebblewhite, G Sharrock

The strength and deformation properties of a rock mass are important parameters influencing the design of civil and mining excavations or structures. The mechanical behaviour of jointed rock masses are controlled by the characteristics of discontinuities and the strength of intact rock bridges between discontinuities. To date, analytical, empirical and experimental methods have not captured the key mechanisms controlling the mechanical properties of actual rock masses with non-persistent joints. The emergence of the synthetic rock mass (SRM) in 2007 provides a promising approach for this purpose. In this paper a rock mass with non-persistent joints is analysed with the SRM model based on PFC3D. The influence of joint geometrical parameters on the uniaxial compressive strength (UCS), rock mass deformation modulus (Em) and failure mode is studied. Joint parameters include joint orientation, persistency, spacing and step angle. Prismatic numerical samples with dimensions 300 mm × 150 mm × 50 mm were generated and a sensitivity analysis of each joint parameter on UCS and Em was undertaken. The results show that of the parameters tested, joint orientation has the greatest influence on UCS. Minimum UCS occurs when the angle between the major principal stress and joint surface is approximately 60°. The joint step angle was found to have a significant effect on failure mode and a joint step angle of 90° is the most favourable joint orientation for step-path failure. The importance of joint step angle is highlighted in the discovery of a failure mode bifurcation point at joint step angles of 60° and 90° for joint orientations of 75° and 90°, respectively. For these parameters the failure mode transitions from block rotation to a new failure mode where the coalescence of cracks results in the formation of new small regularised blocks.

Sep 26, 2011

By Knut L. Sandvik, Erik Larsen

"Estimated global solar energy demand in 2001 required approximately 5,500 tons of silicon feedstock. This required 65,000 tons of quartz. If the trend continues, the solar energy demand in 2010 would require approximately 30,000 tons of silicon feedstock and 350,000 tons of quartz, although the need for quartz probably will be lower than this due to higher solar cell efficiencies, larger and thinner wafers, more extensive recycling of waste material and new routes for the production of silicon feedstock. The raw material requirements for the production of metallurgical-grade silicon are most likely to change. This may favour increased beneficiation of primary raw materials in the future solar cell production chain.SOLAR CELL PRODUCTION CHAIN SCENARIOSThe major problem concerning solar cells is the production costs. Electricity produced from fossil fuels and hydropower plants are currently much cheaper than the electricity produced from solar cells. Also, limited availability of silicon feedstock for the production of crystalline silicon solar cells is considered a major threat to the further growth of the PV industry. The present route for solar silicon feedstock goes from quartz, through metallurgical-grade silicon (MG-Si) and to electronic-grade silicon (EG-Si). The reject from the EG-Si production are further processed into wafers and solar cells. This situation is not satisfying, however, because it has created a silicon feedstock shortage and a PV energy price that is not competitive in a large scale.Crystalline silicon solar cells are the most important solar cells manufactured today. This will most probably remain the situation the next decade. Also, the future silicon ""feedstock"" is most likely not reject from the production of electronic-grade silicon, as it is today. There will probably be a more direct solargrade silicon route, excluding the very expensive electronic-grade silicon ""detour"". Quartzite has been regarded as the most suitable primary raw material used in the silicon solar cell production chain. This may change as the raw material requirements for the production of metallurgical-grade silicon are most likely to change. In addition, quartz or other silica-containing minerals from other rocks may be of a higher purity or contain lesser amounts of the most harmful elements. This favours increased beneficiation of primary raw materials in the future solar silicon feedstock production chain"

Jan 1, 2003

By Jurgens J. Louw, Vincent C. Smith, Gareth C. Smith, Agit Singh, Dave G. Hulbert

"During 2000 Mintek Developed the PlantStar plant wide control platform for the minerals processing industry. The flexibility of the PlantStar control platform has enabled Mintek to investigate and easily develop new control strategies for both milling and flotation. This includes a Solids Feed Controller, a Safety Limit Controller, Mill Power Optimiser and Flotation Optimiser, amongst others.Processes with long dead times, like a feed belt to a mill, are difficult to control. The solids feed controller was developed for minerals processing plants using a specialised time delay compensator. Using conventional time delay compensators that are purely model based, results in robustness problems due to model uncertainties. The Mintek Solid Feeds Controller makes use of a plant model, but compensates for model inaccuracies, giving more controller stability and a more robust delay compensation algorithm.Often there are more variables on a plant that need to be controlled (process variables) than there are variables to control them with (manipulated variables). Process constraints are often reached and violated. Safety control loops are necessary to prevent constraints being reached. The safety limit controller has been developed to switch smoothly between normal and safety control loops without bumping the process. The safety loop output is chosen in accordance with a predefined list of priorities and whether the respective constraint boundaries are exceeded.The Mill Power Optimiser helps to find the power peak on the mill power curve. It continuously perturb the solids feed rate to learn ‘where’ on the curve the mill ‘was’ and then to drive it continuously toward the middle, maximum power drawn. This insures maximum grind with maximum throughput. It also prevents power dips due to mill overloads by cutting the solids feed to a minimum if the power drop below a specified threshold. Once the power rises above the threshold the solids feed is increased again to an intermediate value from where it start the perturbations again to find the maximum. This makes the milling circuit easier to operate."

Jan 1, 2003

By B. J. Scheiner

The Federal Bureau of Mines investigated an electrolytic oxidation procedure for extracting lead, zinc, copper, and silver from lead-zinc concentrates. Concentrates slurried in brine were pumped through the anode compartment of electrolytic cells equipped with selective ion diaphragms. Hydrochloric and hypochlorous acids generated in the anode compartment converted the metal sulfides in the concentrates to soluble metal chlorides, sulfate ion, and elemental sulfur. Metal extractions of 92 to 100 pct were obtained from lead-zinc concentrates at an energy consumption ranging from 1.5 to 5.0 kW-hr/lb metal extracted. Sodium hydroxide was formed in the cathode compartment at a current efficiency of >99 pet. Silver and copper were extracted from refractory tetrahedrite minerals, but the process entailed a relatively high energy consumption. Sealing the top of the diaphragm cell utilized the chlorine more effectively, thereby reducing energy consumption 10 to 50 pct.

Jan 1, 1975