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Supergene nickel sulphide ore mined currently by Agnew Mining Company is at times partially oxidised to sulphate. The resulting soluble nickel, and calcium and magnesium in mill water, are shown to act as depressants in flotation. The depressant effect is favourably selective in that violarite, the main nickel mineral, is less affected than pyrrhotite. Nickel recovery, however, is adversely affected, probably through reduced flotation of complex sulphides. Soda ash consumption is increased markedly by the presence of the cations as shown by operating data and pulp titration tests. A significant increase in concentrate grade, from 9% to 14% Ni, was achieved late in 1981. One of the changes in plant practice which contributed to this improvement was the addition of soda ash to mill feed rather than to flotation feed as before. It is shown by laboratory tests that this reduced the depressant effects of the cations, thereby improving recovery at the expense of rougher selectivity, or equivalently, increasing concentrate grade at constant recovery. The selective depressant effect cannot be exploited until scavenger recovery is improved and a scavenger concentrate regrind-retreat äcircuit is implemented. Development is

Jan 1, 1978

By Hindmarsh G

The colliery is owned by the BHP Collieries Proprietary Ltd., the principal shareholders being the Broken Hill Pty. Company Ltd. and Hebburn Limited.It is situated due west of Newcastle and 6 south-east of Cessnock, N.S.W., and is conneeted by 36 miles of railway to the port of Neweastle. Of this mileage, 3 miles are owned by the Company, 3 by Hebburn Limited, 9 by the South Maitland Railways Ltd., and 21miles by the Government Railways.The seam worked is known as the Main Greta Seam of the Greta Coal Measures and is on the southern slope of the Lochinvar anticline.At the shaft, the seam is 1190 ft. below the surface, and the section of the coal measures is:-Upper or Main Seam, . 24 ft. 0 in.Conglomerate and shale 70 ft. 0 in.'Middle Seam 8 in.Conglomerate 25 ft. 0 in,Bottom Seam 1 ft. 2 in.These lie between two marine measures, and are the lower coal series of the permo-carboniferous period.Only the upper seam is workable in this area, the lower seams being too thin for eompetitive working. The section of the workable seam at the shafts is as shown on Fig. 1.Unfortunately, only the lower 12 ft. 5 in. of the seam is saleable.

Jan 1, 1935

THE Taranaki oil-field is situated on the western side of the North Island of New Zealand, at about its widest part, and may be said to be the most compact and fertile part of the Dominion, for, with the exception of the. upper half of Mount Egmont and of the ranges adjoining, which absorb 36,000 acres, the whole of the area, miuus what is taken up by the rivers land streams-is suitable for settlement, and certainly two-thirds is good land. The gross area oE the district is 2,417,299 acres.The principle rivers are the Wanganui, Mokau, Waitara, Patea, and Waiwakaiho. Mount Egmont, which is 8260 ft. high, used to be called Taranaki, and from it the district takes its name (the Maori meaning of which is "sloping peak ").

Jan 1, 1911

By Chend J

Research conducted into backfill drainage at Mount Isa Mines since 1992 is described. Piping in draining backfilled scopes has been the primary cause of bulkhead failures and emphasis is placed on research into the piping mechanism. Laboratory and in situ tests aimed at understanding the piping mechanism have been conducted and the results are presented. A case history of piping in a draining bench scope fill mass is described and a technique for reducing the potential for bulkhead failures in hench stopes is presented. Hydraulic fill is produced by standard cycloning of tailings and the overflow (reject material) is sent to thickeners prior to placement in the tailings dams. Research into the partial introduction of thickener underflow into the backfill system and its influence on backfill drainage is also descrihed.

Jan 1, 1998

By K Matsui, T Sasaoka, S Kubota, Y Yosh

A large amount of wastes from the preparation plant is produced. The properties of these wastes vary depending on the mineralogical contents of the mother rock in which the coal is embedded. The waste quality depends on the method of mining and cleaning. The waste mainly consists of clays, quartz, carbonaceous materials, mica, pyrites and so on. About 55 per cent of coal-ash is now utilised and the remains are disposed of at the disposal sites, however, the life of the disposal site is limited. Moreover, it is difficult to find new disposal sites. Therefore, it is requested that the percentage of the utilisation of the coal-ash be increased in every field in Japan. So, it is very much available if the injection material for natural/artificial openings can be applied on the cement that is added to flyash. Among the man-made pozzolans, a flyash is probably the most successful component used in grout injection. When flyash is added to Portland cement concrete, the same kinds of oxides as those of the cement are being added. As an injection component, flyash acts, in part, as a fine aggregate and, in part, as a binding component. However, there is not a substantial alteration of the properties of the original component. From these points of view, in order to clarify to what degree the flyash content affects the properties of the injected grout mixture; different combinations of flyash, Portland cement and water were considered by means of several experiments.

Jan 1, 2003

In order to maintain an accurate survey underground, it is first necessary to connect all shafts used for the transferring of the survey to the levels below by a precise surface survey.This has been achieved at Mount Isa by a careful triangulation survey with stations adjacent to those shafts most suitably located for transferring the survey below.The precedure used is described herein.The Weisbach triangle commonly used is obtained by reading to swingirig wires, the theodolite being placed in line with them as nearly as is possible. The surveyor at the surface places the wires in the shaft as far apart as the size of the shaft will permit, with sufficient space between the wires and walls to ensure their swinging freely. The far wire is fixed in position, while the near one is movable by means of fine adjusting screws to facilitate its being brought into line with the fixed wire and the theodolite. When this is done the surveyor at the lower level is advised by pre-arranged signals and the survey can then commence.The surface portion of the survey is simple; all that is necessary being to read the angle from the backsight to the wires, measure their distance from the theodolite, and keep a check on them throughout the survey to make sure that no movement takes place.The lower portion of the survey is more difficult, the surveyor first qf all having to place his theodolite as nearly as possible in line with the wires.

Jan 1, 1953

By S Brochot

In cases where coarse gold is present in a deposit, it is usual to use the screen fire assay (SFA) method to analyse the samples. There is no doubt that this method is more accurate than the standard fire assay (FA) and reduces the risk to have a systematic bias. Nevertheless, the difference between the analytical errors of both methods can be glossed over when the overall sampling error is added to obtain the measurement error. In that case, the advantage of the SFA cannot justify its higher cost.The current paper attempts to address this question in the case of a gold ore deposit with visible coarse gold in various sampling situations (drill core sampling in exploration, blasthole or chip sampling in mining exploitation). The overall measurement error is estimated taking into account the analytical error and all the sampling error components following the Pierre GyÆs theory of sampling.Firstly, only the last sampling stage is considered when the pulverised sample is processed either to obtain one analysis sample for a FA or to be screened and subsampled for a SFA. The calculated measurement error clearly shows the advantage of the SFA specifically in presence of coarse gold. Secondly, the half core sampling is studied to explain the observed discrepancies when controlling the second half core. Finally, the blasthole sampling is treated using in situ heterogeneity models to show that the relative advantage of the SFA is hidden by the large overall sampling error.In conclusion, the choice of the assaying method is discussed at the light of the overall measurement error and in accordance to the analysis objective.CITATION:Brochot, S, 2012. Standard fire assay or screen fire assay? Application of the overall measurement error approach to choose the most appropriate method, in Proceedings Sampling 2012 , pp 135-142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

We operate a 50 cubic metre per hour mobile alluvial tin mine on small scattered deposits in the Irvinebank area. Wash is loaded by a Cat. 950 front end loader into the bin of a screening section and screen undersize is pumped to a separate jig unit. Both units are rubber tyre mounted and are shifted once a month when the haul distance gets to about 150 metres. The shift takes about 8 hours.The screening section is sited close to the face with a ramp for dumping in and a one metre drop for the screen oversize which is removed by the loader.A reciprocating plate feeder with variable rate hydraulic drive, feeds wash onto a horizontal 1.2 metre x 2.2 metre two deck Kinergy screen. Minus 10 millimetre undersize is pumped by a Warman 6/4 sand pump with a 37 kW variable speed Reeves Motordrive to the jig unit.The jigs are placed 20 to 70 metres away so that tailings will run back into previously mined ground. Reject stone is used to impound the sand and mud, allowing the water to filter through and return to the feed water pump.An MTE trapezoidal module is used as a primary jig. Hutch product is pumped to an eight cell clean-up jig which we developed ourselves along MTE lines. It has a trapezoidal shape and sawtooth stroke provided by cams. Clean tin is taken from the first four spigots. These consist of clear plastic tubes fitted with taps so that there is no water loss except when the tin is drawn off. Fine concentrate from the last four spigots is put over a curvilinear table which sits on a steel base packed with earth.

Jan 1, 1986

The Que River Mine is a small under-ground base and precious metals mine located in north-western Tasmania. Current production rate is 220,000 tonne/yr from reserves grading 0.37% copper, 7.1% lead, 12.2% zinc, 195 g/tonne silver and 3.4 g/tonne gold.Ore is mined using longhole open stoping techniques. Cemented fill is placed in primary stopes to permit safe and efficient recovery of pillars. The operation is trackless with both shaft and decline access from surface.Ore produced is trucked 40 km by road to be sold to the Electrolytic Zinc Company of Australia Ltd., for treatment at their Rosebery concentrator.

Jan 1, 1985

The theme of this Annual Conference of The Australasian Institute of Mining and Metallurgy is in the form of a question: `Adding Value to our Resources - Our Future?' There are two ways of looking at this question. The first is to assume that any mineral or energy resource is worthless until it is identified, recovered and put on the market. In this sense all our current operations, be they open cut coal mines or aluminium smelters, are engaged in adding value. The question then becomes: what is the future of the minerals and energy resource industries with which we are familiar - will they grow or contract? The second way is to emphasis the value-adding aspect. The question is now one of whether or not our future depends on adding further value to resources we are currently selling.

Jan 1, 1995

It is now 32 years since Walsh's classic publication (1) heralded the beginning of atomic absorption spectrophotometry (AA) as we know it today. During this time, AA has developed into the most widely used analytical techniques for the determination of the metallic elements. The years have seen progressive changes in instrumentation so that today it is a highly sophisticated technique. One area of development in AA that is experiencing renewed attention is in the area of electrothermal excitation. In this technique a flame is not used by the analyte solution is atomised by an electrically heated graphite furnace. For a large number of elements the graphite furnace atomic absorption spectrophotometer (GFAA) is considerably more sensitive than flame work. It is common to be able to detect concentrations one hundred times smaller than those possible by flame. Today's geochemists are finding that they can gain valuable information out of very low limits of detection. Electrothermal atomic absorption spectrophotometry (or GFAA) allows for low limits of detection and can be seen to be a valuable aid to geochemical prospecting Analysis.

Jan 1, 1987

An on-stream iron ore analyser has been developed in collaborationwith Hamersley Iron Pty. Limited for determining the iron content ofboth lump (- 30+ 6 mm particle size) and fines ( - 6 mm particle size)on conveyor belts. The analyser, which is called IRONSCAN, is basedon pair production, and is now commercially available from Mineral ControllnstrumentationLimited (MC!) in Adelaide. It can be mounted underexisting conveyor belts with minimal modifications to the conveyor structure,and the presence of steel cables in the belt does not interfere oncethe analyser has been correctly calibrated. The analyser has been extensivelytested on both lump and fines on the shiploading conveyor at Dampier,and typically the root mean square (Lm.s.) deviation between singleIRONSCAN measurements and conventional chemical analyses is betterthan 0.5070 Fe. It is currently being evaluated on - 150 mm ore from theprimary crusher at Mount Tom Price, and initial result are encouraging.The principal advantage of IRONSCAN is that it provides rapid informationon ore grades. But perhaps its greatest potential is at the primarycrusher where conventional sampling and analysis is very expensive toimplement.

Jan 1, 1988

The intention of this paper is to examine the practical and technical aspects associated with the measurement of blasting related phenomena. The emphasis is directed towards the acquisition of quantitative data rather than its theoretical interpretation. The application of advanced technologies will require that many more people involved with blasting become familiar with this topic. Against the many other disciplines where measurement may be beneficial, blasting is peculiar on several counts. 1) It must almost always be carried out in the field, and very often in a production environment. 2) Much consideration must be given for the safety of personnel and equipment. 3) The process is dynamic and seldom repeatable. Because the blast process is so dynamic there is little opportunity for direct examination. For this reason measurements are almost universally made using electronic techniques. In this way the event can be captured faithfully as it occurs and later examined in detail, after the fact. It is obvious that some familiarity with these electronic techniques is a necessary ingredient for successful blast monitoring.

Jan 1, 1990

The subject of the present paper will be combustion of fuel and as the combustion of fuel requires a certain amouut of air to effect combustion the question might be asked what is air?Air is composed, we will say, principally of two gases, oxygen and, nitrogen, but our business is with the former gas, and its leading feature as a supporter' of combustion. In point of fact no fire will burn without its presence, nor can animal life be sustained when this gas ls absent, because it is the life-sustaining element. For example, if we take a piece of charcoal, which is pure carbon, and burn it in the open air combustion takes place in the union of the carbon of the charcoal with the oxygen of the air, forming the compound known as carbonic acid (0.0.)The rust we see on iron and other metals is a kind of slow combustion, which is termed oxydation. When oxygen unites with any other element heat is given off in the process, and it may be here stated that the most intense heat is produced, by burning the two gases-oxygen and hydrogen in precisely the same proportions as that forming water.

By R Grogan

The Ungay-Malabago polymetallic deposit, currently owned by Lafayette Mining, is located on the eastern end of the island of Rapu-Rapu which lies east of the city of Legazpi in the Philippines. The island is sparsely populated and has largely been deforested by extensive logging some 30-40 years ago.The deposit is situated on a plateau some 200 m asl and lies about one kilometre inland from the coast. The site topography is difficult with minimal flat areas for plant facilities. The region around Legazpi is subject to volcanic activity and though the island is not affected it is in a seismic zone. There is no other mining or other industrial activity on the island, the local inhabitants being engaged in subsistence farming and fishing. These activities place a high level of responsibility on the mine operator with regard to the environment and the provision of employment and training to the local inhabitants. Although no previous mining was carried out at Ungay, shallow pit mining for high-grade direct smeltable copper ore has occurred during the mid-1900s in an area, known as Hixbar, some 2 km west of the deposit This area is currently being explored by Lafayette.

Jan 1, 2002

By Hinrichsen H. D, Rathburn D. R, Stieger W

The present situation in the field of iron ore pelletizing is briefly described with particular view of the Lurgi/Dravo travelling grate process. To meet todays pellet quality requirements with regard to physical and metal- lurgical properties it is often necessary to add basic fluxing materials. It has been de- monstrated that for certain ores, basic addi- tives provide a considerable improvement in fired pellet quality. The production of self- fluxing pellets is becoming increasingly attractive. One Lurgi/Dravo plant is now in operation and another is under construction which were designed for the production of self- fluxing pellets. Self-fluxing pellets may be considered as the primary or exclusive blast furnace burden and the installation of a sinter plant is not necessary if the pellet plant-can handle all in-plant fines. Reference is made to the first pellet plant utilizing iron ore concentrate, in-plant fines and basic flux. The use of solid fuel for pellet indura- tion is discussed because of the increasing prices and possible shortages of heavy oil and natural gas. Since there is a strong tendency to increasing plant capacities, the design fea- tures of travelling grate pelletizing plants for productions up to 6 million tonnes are Discussed.

Jan 1, 1974

By Wagland D. G, Guo H

The Mt Whaleback orebody is in a complex geological regime. A good understanding of geological structure is essential during the design and implementation stages. The amount of information on the rock-mass condition available at the design stage is considerably limited. It is essential to validate the rock-mass properties used in the design during implementation. It is important to achieve integrity of the final pit wall during development and to maintain the integrity until the end of its designed life for safe and economical extraction of ore. The original geological model is updated by way of on-going detailed geological face mapping. Original design is reassessed and is modified based on any significant variations to the previously evaluated geotechnical conditions. Information gathered during design implementation provide tools for effective management of the pit walls. Controlled blasting techniques are employed in the final limits blasting. Presplit blasting is used in most limits blasts. Presplit helps to maintain the integrity of the wall by venting excessive gases from the limits blast. This helps to reduce bedding dilation by gas penetration. Also, it helps to define the design batter for the operators for final batter trimming. Pyritic shale needs special attention during blasting due to its reacting nature. Cablebolting is applied in selective areas to secure small-scale potential instabilities. During the development phase, pit wall monitoring instruments are installed. These instruments are used to monitor the performance of the wall during and after excavation of the slope.

Jan 1, 1995

Pongkor Gold Mines is one of seven units of production owned by PT Aneka Tambang (State owned mining company). The mine is located in the western part of Java Island, Indonesia. It is in the Bogor District and approximately 110 kilometres to the south of capital Jakarta. It is located in very steep hilly terrain intersected by many river valleys and the mine site is approximately 500 metres above mean sea level (see Figures 1 and 2 - Mine location map and picture)

Jan 1, 1997

The orebodies at Kambalda are complexly faulted, folded and intruded. It is realized that the ore reserve calculations will be wrong and steps are taken to minimise the errors. The calculations are a combination of computer data handling and manual input. Initially Geological Ore Reserves are calculated and then production data and experience are used to produce a Planned Mining Reserve. At all stages maximum professional judgement is incorporated. The basis of the calculation is the polygonal method of area estimation, and production reconciliations together with the style of data available indicate that it is a most suitable technique. It is also a tech- nique that is easily communicated to all levels from operators to management.

Jan 1, 1979

The development of computers is examined in the context of the mining industry. The risk element is given as a reason for the slow introduction of the computer into mining. Dealing with mining's uncertainty is seen as a major role for computers. The use of computers is traced from early accounting applications to current involvement with all aspects of mining. The problems associated with increasing use of computers and their impact on management is discussed in depth. Disenchantment of management is thought to arise from unfulfilled expectations. Contributory causes are given as overselling of computers, reaction against change, speed and growth of computer technology. The solution is seen to lie in a more dominant role for user management in the development of computer systems and greater emphasis on education. The computer of the future will then become integral to the mining process as an extension of management's planning and control function.

Jan 1, 1974