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An exploration and preliminary mine design contract was undertaken in Thailand to establish whether adequate lignite resources existed for the addition of future power generation plant through to the year 2000. The lignite ranges in heat value from 14 to 24 MJ/Kg (air dry basis) and occurs in 2 major seams consistituting measured reserves of 536 Mt (with an ash cut-off level of 45 % on an air dry basis) and a strip ratio of 4.1 bank cm/t. The paper describes the pre-planning, programming, equipment used, project management, logistics and exploration methods adopted to undertake the contract in a monsoonal area using Australian drilling and geophysical contractors.

Jan 1, 1983

By Sakai S, Suga S, Bisque RE

Soil gases were collected on activated charcoal, analyzed by computerized mass spectrometry and treated with multivariate statistical pattern recognition to determine the diagnostic geochemical signature associated with the Okuaizu Geothermal Field in Japan. From this a geothermal model was developed and compare to 175 "unknown" samples in a 250 m spaced grid over 30 1Qn2 mapping the areas with a matching geochemical character. Faults and fractures were generally located by the presence of high molecular weight components. Following the initial survey, the faults in two specific areas were precisely located by a second survey with samples at 10-30m spacing. Where earlier geochemical surveys had placed anomalies 1-2 Km northeast of the geothermal center, the fingerprint survey accurately mapped the system and detected several faulted zones. It was not misled by hot springs located away from the geothermal System.

Jan 1, 1987

A 1991 survey of 48 mining companies, employing more than 24 000 employees, showed that disabling injury and disease rates continue to be the most common measurements of safety management effectivness in the Australian mining industry.Of the companies surveyed, 22 claimed to be making regular safety audits. Of these only two listed the improvement of audit scores among their goals for 1991.Influenced by loss control management thinking, some managers have expanded the scope of their safety programs to include all accidental operational losses adversely affecting mine profitability.Learning from their new experience with total quality management some managers are now recognising that successful safety management outcomes depend on the effective management of program inputs. They are thus turning away from measurements of accident consequences - the failures of the management system - to measurements of management control.The new focus of safety management attention is now on corrective actions before accidents happen.

Jan 1, 1992

By J Boland

Polycrystalline diamond compacts (PDC) have been widely used as cutting elements in the drilling tools for the oil, gas, civil and mining industries because of their faster penetration rates and longer bit life. US Department of Energy reports that PDC bits account for more than one-third of the total footage drilled worldwide (US Department of Energy, 2004). However, non-thermally-stable diamond composites (NTSDC) have seldom been applied to geothermal drilling, since premature failures of such PDC cutters have been observed in hard rock formations. Several factors need to be considered to prevent premature failure of cutters and improve cutting performance when using PDC-based bits and other rock cutting tools. The first set of factors consists of the strength, density, stiffness, toughness and thermal resistance of the PDC and the rock. A second set relates to the complex behaviour of the bonding between the PDC cutter and the bit matrix, or the pick and the pick holder, which is vital in maintaining stable, reliable and durable adhesion of the cutters to their hubs. Finally, based on a better understanding of the cutting processes, the formulation of a predictive model would assist in further development of cutter design.

Jan 1, 2004

Physical model testing at Bergbauforschung is done in two rigs, a roadway rig and a longwall rig. The loading of such models, in scale relation to the con- ditions in the collieries provides valuable guidance to the probability and nature of failures, and thus to support requirements, in structural, roofbolts and self- auvancing supports. The success of such modelling when related to subsequent underground designs put to use suggests that such methods of investigation could be extended to pillar extraction problems also.

Jan 1, 1974

The economic significance of a fundamental understanding of the mineral pyrrhotite is dis- cussed. Particular emphasis is placed on the relationship of other sulphide minerals to the pyrrhotite when it is the major sulphide mineral present in an ore body. Studies of the Kambalda nickel deposit are used to give a better under- standing of (a) the genesis and other character- istics of a particular ore body (b) the textural relationships between pyrrhotite and other sul- phide minerals (c) magnetic properties of natural pyrrhotite, and (e) the oxidation and supergene processes that take place in a sulphide ore body.

Jan 1, 1972

By Rao S. B, Baafi E. Y

A venturi based multi-scrubber air cleaning system has been developed for dust control along a longwall face in coal mines. The system consists of a number of scrubbers. strategically placed along the wall face which deliver cleaned air at high exhaust velocity into the middle section of the longwall cross-section thus dividing it into two zones. The aim is to maintain the walkway on the powered support side as a zone of relatively clean air. Laboratory studies have shown that the scrubber's average efficiency is 90 per cent. Field trials in three longwall faces have shown that. under normal operating conditions. 40 to 50 per cent average protection efficiency can be achieved within 3 m to 4 m downstream of the scrubber. A three-dimensional finite element computational fluid dynamic model. FIDAP. was used to simulate the airflow patterns the dust concentration and the scrubber dust control technique at a typical longwall face. Results of simulations tally very well with the field results.

Jan 1, 1995

By Brinkmann J. R

In the narrow stopes of South African gold mines, rockbreaking is carried out by drilling and blasting with safety fuse and igniter cord being used as the initiation system. The fuse/gniter cord system is used primarily because of its low cost, however several limitations of this method include: inaccurate delay time, unreliable firing, inflexible application to varied configurations, and the absence of dynamic interaction between holes. Alternative initiation systems that incorporate millisecond timing are being developed to overcome the limitations of fuse(tgniter cord systems. Current investigations by the Stoping Technology Division of the Chamber of Mines Research Organization (COMRO) into the effects of millisecond initiation are being conducted at a deep test site. Experimental blasts using various millisecond delays and the independent firing of holes with fuse/igniter cord are being studied in order to quantify the influence of delay time on the blasting process and to identify the best methods of applying millisecond initiation systems. The effect of design variables such as delay time, hole firing pattern, stemming, and panel layout are discussed. Blast results including throw distance and direction, muckpile profile and rock cleaning times are used in the discussion of different combinations of blasting variables.

Jan 1, 1990

The paper describes the 209 in. single stage axial flow mine ventilating fan which commenced operation at The Zinc Corporation Limited, Broken'Hill, N.S.W., in January, 1954.This fan is used to ,ventilate the underground workings of The Zinc Corporation Limited and New Broken Hill Consolidated Limited and, at the time of installation it was the largest fan of its type in the world. It has amaximum capacity of 900,000 c.f.m. at 4·2 in. watergauge and is equipped with adjustable pitch blades and a novel form of variable speed drive.The considerations which lead to the adoption of this particular design are outlined, and a full description of the contruction and installation of the fan and auxiliaries is given.Comprehensive acceptance tests were carried out on the completed installation and, the testing procedure is described in detail. The results of sound level measurements are also included. A brief report on the performance during the 12 month period from 1st July, 1954, to 30th June, 1955, is then given.SELECTION AND DESIGN OF FANGeneral ConsiderationsBecause of the economic advantages of joint ventilation of the underground workings of The Zinc Corporation Limited and New Broken Hill Consolidated Limited, it was decided, after a full review of the future ventilating requirements of both mines, to sink a 20 ft. diameter circular upcast airway on the common boundary of the two properties, to handle a maximum quantity of 900,000 c.f.m.The anticipated air requirements were at this stage estimated to be:(a) initially 700,000 c.f.m. through a mine equivalent orifice of 160 to 2'40 sq. ft. (equivalent total pressures being 2·70 in. w.g. and 1·20 in. w.g.) ;

Jan 1, 1956

By Tapp B. A

The minerals industry in Australia is currently regarded as the country's economic saviour; the bastion of economic security. As Fitzgerald (1974) stated, 'Australia's natural endowments in minerals are the envy of most countries of the world'. As a result the proposed new mineral developments are on a scale that hitherto in the sixties would have been completely unenvisaged. It is reported that Australia is poised on the verge'of a sixteen billion dollar mining-based investment boom: a boom that will see Australia dominate the energy export field, the mineral processing field, and create the 'coal dollar'. This growth scenario has many inherent dangers, and it is the authors' contention that these should be carefully considered before further development proceeds. Two of the major problems related to the mineral industry growth scenario are the predictability of the future metal market, and the energy cost of mining. The latter problem is the one discussed here. The mining-mineral processing industries in Australia currently use about 36% of Australia's primary energy

Jan 1, 1980

By Vynne J. F

Drill monitors for blasthole and exploration drills have been available to the mining industry since the 1970s. The early monitors were pen strip chart recorders which were developed for the oil drilling industry and adapted to mining. They recorded drilling parameters such as depth, pull-down pressure, torque, RPM, and bailing air pressure. While these recorders could generate a large volume of paper, the amount of useful data was minimal. The data was not summarised and required an engineer to interrupt the chart traces. Being a mechanical recorder, the devices were also susceptible to frequent failures.

Jan 1, 1993

By Hsiung SM, Jiang YM

The orientation and location of the hydraulic legs are two very important parameters for the design of shield supports in longwall mining. Studies have shown that leg orientations and locations of a support determine the magnitude, orientation and location of the resultant support resistance which in turn affects the efficiency of the support and the ability to prevent premature roof falls in the face area. Therefore, there is a need to determine the best combination of orientation and location of the hydraulic legs for each type of shield support under various geological conditions. This paper attempts to evaluate, first, the individual role of each parameter (orientation or location) and then to determine their integrating functions in terms of ground control employing finite element analysis. Three types of shield support (2-leg and 4-leg shields and 4-leg chock shield) with various combination of the parameters are simulated and their effects are discussed. The optimum design for each parameter for each support type under various geological conditions is also discussed and recommended.

Jan 1, 1988

A microcomputer based expert system is presented for fast and cheap mineral identification. Because of the increasing pipularityof and interest for minerals and precious stones (selling, hobby polishing, collecting, teaching etc.) we pointedly deal with gemstone identification. In most cases only some fundamental data are needed to identify a mineral sample (or precious stone) if we know how to use these data. The important, characterizing data of the well-known minerals are stored in the data-base of our program-system. The visible and measured optical and physical properties of the sample are compared adequately with the stored data to get the result, the name of the examined mineral. The system works in a simple, friendly way - asking questions, understanding answers - so that no special computer knowledge is necessary to use it, only the answers should be typed in. The main advantage of the system is that only relatively simple and fast measure-ments are required. Based on these measurements a fast, reliable identification is processed on a cheap com-puter running a sophisticated program-system. The MINTEST system handles even those cases when the tested mineral cannot be determined based on the given input data.

Jan 1, 1985

By Blackwood R. L, Crichton G. P

In recent years, the value to Australia of the introduction of a system of resource rent taxation on the mining industry has been frequently debated. The forms that this rate of return based tax could take, and the impli- cations on government revenue and mining com- pany profitability have been discussed at some length. Further, the selective application of this taxation scheme to certain mining industry sectors has received considerable attention. This study takes the form of a survey of the taxation history of one significant Australian mining venture, the Mount Lyell Mining and Railway Company. The conditions faced by this company during its history are used as a base for the imposition of rent taxation schemes. Comparisons are drawn between the historical taxation liability of the company and that which would have been incurred if a resource rent form of taxation had been in existence. From the results of the study, it can be concluded that while the company can be con- sidered to have been a successful enterprise during most of its history, it has not achieved a level of profitability which would warrant the collection of any form of excess profits Tax.

Jan 1, 1979

By Cunningham J. C

JUST prior to the war the Broken Hill South Ltd: raised, on the average, 6628 tons of ore per week, all of which was crushed and treated in the 4-section gravity mill and the slime flotation plant, for the recovery of lead concentrate carrying silver. The sandy residues from that treatment were railed to the treatment plant of the Amalgamated Zinc (De Bavay's) Ltd. for the recovery of zinc concentrate by flotation, on the joint account of both companies. Subsequent to that-since 1916-approximately 1000 tons of old dump slime were also treated weekly for the recovery of lead and silver as slime-lead concentrate.PLANT CAPACITYUnder this programme the Babcock and Wilcox boiler plant of 8 boilers was taxed to such an extent as to call for the installation of two additional boilers, each of 2690 sq. ft. of heating surface and 55 sq. ft. chain-grade area.The electric generators and the air compressors of the old powerplant were also loaded to their maximum capacity. In view of the fact that the old power-plant had been added to from time to time since 1901, and that further extension was notpossible, and as it was not, moreover, an economical arrangement, the whole question of power generation was reconsidered. The considerations that determined the installation of entirely new plant were as follows:(1) The need for more compressed air for underground work and more electric current for the extension of the slime-flotation plant for the recovery of zinc, as well as lead, as slime concentrates. Provision of additional power was also deemed advisable for the...

Jan 1, 1921

Conventional narrow vein mining, utilising hand held methods, is expensive and requires specialised miners who are becoming a rarity. Hand held mining techniques (shrinkage stoping, leading stoping and cut and fill) have the advantage that they can be selective. The methods allow continued sampling of the face, control of hanging wall conditions and are adaptable to changes in strike and dip. On the other hand, more productive longhole stoping methods can allow excessive dilution due to drill hole deviations and changes in orebody dip and can be subject to unexpected hanging wall or footwall failures. Development of small scale equipment (as narrow as 0.8m wide) used for drilling or bogging very smallaccess drives has been ongoing over the past decade. In this paper, types of equipment are examined and compared, particularly with respect to their produc- tivity, size, and working environment. The introduction of electric hydraulic equipment has provided a better working environment with reduced noise, exhaust fumes and heat. The concept of the "hydraulic cherry picker" may have application in mining steeply dipping orebodies. The system requires orebodies to be reasonably consistent in dip over 15 metre sub-level intervals. The system involves the basic concept and skills of machine and airleg mining, combined with the safety and productivity of a mechanized work platform. The platform or basket is stabilized between the hanging wall and foot- wall by hydraulic rams and is extended by a tilting hydraulic boom mounted to a small prime mover or trailer. Design concepts (including remote controlled charging of explosives, adaptation to the boom for rock cutting and the overall electric hydraulic mining concept) are put forward in the paper as a view as to how narrow vein mines will be mined in the future.

Jan 1, 1987

By Cocker J, Urosevic M

Seismic methods have become common for the detection of low-throw faults ahead of underground coal mining. Surface seismic methods cannot theoretically be used where dykes occur, because seismic waves transmit from the surface down to the seams, and reflect back to the surface. Consequently, where sub-vertical structure such as dykes occurs, the surface seismic method fails.The ability of seismic methods to image dykes depends on the geometry used, the dyke thickness and the seismic wave propagation mode in relation to dyke composition and internal structure. Surface seismic methods find it difficult to distinguish between faults/fractures and very thin dykes (1-2m in thickness) when the dyke's thickness is less than the seismic wavelength. Consequently, borehole seismic methods have to be used to detect the presence of such thin dykes.

Jan 1, 1998

By Larsen D. F

Minor iron formation related base metal sulphide mineralization occurs in granulite facies metamorphic rocks of the early Proterozoic Willyama Complex. Rock sequences hosting three iron formation related Cu, Zn, Pb prospects from the Thackaringa Group (Suite 3) are described. A caparison of host rock sequences, style of mineralization and facies of iron formations suggests major differences in terms of the overall depositional environment. However, significant similarities are present with respect to the nature and distribution of iron formation facies and the occurrence of chlorite 'alteration' zones in close proximity to mineralization in all cases. The chlorite within these zones occurs in a number of diverse forms in a range of rock types. A comparison of the prospects shows that there is no evidence to indicate that the chlorite in the zones is a retrograde alteration product of former higher grade prograde mineralogies - the chlorite appears to have survived granulite facies metamorphism. The mode of occurence of the chlorite in the 'alteration' zones together with the fact that the association quartz + chlorite + magnetite + pyrite + base metals is cx rmn to all areas suggests that the chlorite is specifically related to the processes which deposited the stratiform iron formations and related sulphides. It is considered that the chlorite precursor was a prenetanorphic alteration product or chemical sediment closely related to submarine hot spring activity which was also the source for chemical sediment precursors of the iron formations, associated lode rocks and Sulphides.

Jan 1, 1983

By Hamblyn S

Oakbridge, in combination with its joint venture partner, Nippon Steel of Japan, is expanding its Bulga underground and open cut mines to meet the growing demand for coal in the Asian market. Expansion works underway will see the Bulga underground mine become a world leader in underground productivity, the introduction of a high capacity dragline into the open cut mine (largest capacity dragline in NSW) as well as a major upgrade of the coal preparation plant (CPP) and coal handling facilities (CHF) to process the increased production. This paper describes the planning and implementation of this major expansion program and highlights the rationale behind some key aspects of the program.

Jan 1, 1995

By Caelli T, Robey M

Most research into planning of open pit mines has been based on evaluation of volume-element block models in terms of their net present value. The major issues revolve around two interdependent problems the optimum ultimate pit and time-based scheduling. Despite feedback between the two problems, they are usually treated as separate tasks.The ultimate open pit is defined by the removal of whole blocks so that their net present value is maximised. This gives planners an estimate of the total worth of the venture in present terms, and is crucial to obtaining funding. All cost and profit values are assumed to be static throughout the mine life, and the only physical constraint usually taken into account is that of safe, average, wall slopes, which must be approximated by the removal of whole blocks. Modelling of any further constraints (for example, access roads and true wall slopes) is usually achieved by adding them to the optimal pit by hand. Typically this degrades the model by between five and 20 per cent of its value - which then brings into question whether it is still the true optimum.This paper reviews the dominant methods in use for this first task the ultimate open-pit planning problem. Some new optimisations are given, and the algorithms are examined in terms of their efficiency and accuracy. Finally, suggestions are made for improvement of model accuracy and eventual expansion into solutions of the more complete dual problem - that of simultaneously finding the optimum ultimate pits and dynamic schedules for the venture.

Jan 1, 1996