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By Muir D. M

Highly saline process water has a number of implications for the CIP process during the leaching, adsorption and recovery of gold. The reduced oxygen solubility in saline water can seriously reduce the rate of gold leaching, while dissolved oxygen meters do not necessarily reveal actual oxygen concentrations in saline water. High levels of magnesium in the ground water necessitate operation at lower pH (-9), with the potential for greater cyanide loss via HCN stripping. In addition increasing salinity renders viscosity modifiers largely ineffective.The adsorption capacity of aurocyanide onto activated carbon is improved with increasing salinity, but misleading results can be obtained in assessment of gold loading kinetics of plant carbon samples already loaded, or partially loaded, in saline water if subsequently tested in fresh water. Elevated chloride levels in the Zadra elution process can cause severe anode corrosion in the elecuowinning cell. The Anglo elution process is tolerant to only slight increases in water salinity, but elution times can be reduced by ethanol addition. Care is required in carbon regeneration, as salts can catalyse carbon decomposition as well as increase kiln corrosion.

Jan 1, 1994

The first continuous pressure disk filter took up industrial-scale operation in Germany in 1976. This paper comments on major components of pressure filter facilities from the point of view of industrial-plant suppliers. For lack of time aspects of economy have not been commented upon. The paper elucidates a number of process-engineering inter-relations. It outlines important development trends from the angle of a machine-building company.

Jan 1, 1989

During the past 18 months several import- ant hydrocarbon discoveries have been made in the Dampier Sub-basin, which is a sedimentary area lying entirely offshore from the Precambrian Pilbara Block in the southern part of 'he Northwest Shelf of Western Australia. This sub-basin is a major sedimentary downwarp forming a northern extension to the Carnarvon Basin. This extension is bounded to the north by the De Grey Nose, separating it from the Beagle Sub-basin. To the south the Dampier Sub-basin merges with the Barrow Sub- basin. Extensive seismic data combined with results from exploration drilling show that the Dampier Sub-basin is a complex depositional basin containing over 20,000 feet of sediments which are mainly Triassic to Recent in age. Tectonically the sub-basin can be divided into seven main structural elements. In a northwest to southeast direction these are the Rankin Platform, the Kendrew Trough, the Madeleine- Dampier Trend, the Lewis Trough, the Legendre- Rosemary Trend, the Enderby Fault Zone and the broad Pilbara Shelf. Permian sediments were encountered in only one well drilled to date in the sub-basin, but Triassic and younger sediments are extensive. The section consists initially of 'hi -_D 7 ri ,~ ~, , i , Derived

Jan 1, 1973

By Sullivan BJK

The 1100 orebody is a massive copper sul- phide orebody which contains a major portion of the Isa Mine copper ore reserves of 130 million tonnes at 3.2%. The underground mining of a deposit as large as the 1100 orebody is technologically a complex operation as extraction strategies have to be evaluated with reference to 1. rock mechanics considerations, 2. safety and environmental standards, 3. production and operating require- ments and 4. metal recovery and costs. The mining philosophy in the orebody has undergone considerable change over the past five years as a result of experience and improved technology. At this stage, primary stopes are extracted by high rise sublevel open stoping and pillars by slot and mass blast drawn either under rock fill or as an open Stope.

Jan 1, 1978

Recent geological mapping has indicated changes to the stratigraphy of the Pine Creek Geosyncline. The new stratigraphy and interpreted depositional environments are examined in relation to the distribution and genesis of stratabound mineral deposits. Basinward correlations are made with near-shore carbonate and psammite-rudite units in the Rum Jungle region. Most other units in the same region are condensed, indicating long- lived supratidal, intertidal or shallow conditions during most of the depositional cycle. Units containing most of the mineralisation represent the earliest near-shore developments of strongly reducing partly pelitic and evaporitic conditions and contain mainly uranium and base metals. Restricted distal, strongly reducing facies with associated felsic volcanics are also well mineralised, and mainly contain gold, silver and base metals, although some deposits are probably genetically related to synorogenic or postorogenic granites. Mineralisation in other facies is almost all epigenetic hydrothermal in origin, although minor mineralisation is related to volcanics, or dolomitic parts of the sequence. Areas of potential mineralisation include near-shore environments in the north, and carbonate reefs along growth faults. Two suites of postorogenic felsic volcanics and related sediments deposited in shallow water within and around northwest and east-northeast rift systems, overlie the metasediments of the Pine Creek Geosyncline in the south. The suites have potential for volcanogenic deposits, mostly of uranium, gold and copper.

Jan 1, 1984

By Godresse M, Turczynski G. P J, Driver I. J, Low G, Ozawa N

Geological evaluations of coal deposits have been traditionally undertaken in a somewhat manual manner. Information is collected downhole by chip sampling, coring and using downhole geophysical logging. This information is then interpreted by an experienced geologist to define the coal and noncoal lithological units. Coal units were subsequently correlated to provide data for structural modelling. In recent years a number of advancements in interpretation techniques have been made based on Artificial Intelligence. This paper describes an integrated geological interpretation system based on maximised use of Al techniques. The first part describes the lithological interpretation which uses a number of boreholes with both logged lithology and downhole geophysical logs. This information provides a learning set of data to the neural network. The second part concentrates on the correlation of both coal and noncoal units from borehole to borehole. Problems in this area, in a manual sense, are interpretation of correlation across weathering zones and other geological anomolies. The technique is based on pattern recognition and dynamic programming techniques where a correlation matrix is developed relating all holes with their maximum correlations.

Jan 1, 1995

By Sorokin M, Komkov A, Fyodorov A

The Vanyukov Process is a high-intensity smelting system that has been proven over the last 20 years for various metallurgical operations including the smelting of copper, nickel, copper-zinc, antimony concentrates, municipal waste treatment and pig-iron production. Extensive pilot plant tests on copper and copper-nickel concentrates have provided information for the design of the commercial furnaces. The thermodynamic analysis, design idea and the data obtained from commercial furnaces have shown that Vanyukov Process would be the best choice to smelt copper-nickel and nickel sulphide concentrates as well as oxide nickel ores.

Jan 1, 1996

By J Andrina, D Richards

The Grasberg is a large copper and gold open pit mine operated by PT Freeport Indonesia and located in the high equatorial mountains of Papua Province, Indonesia. The climate is alpine/sub-alpine with little seasonal variation in temperature and rainfall. The annual precipitation varies from about 3000 to 5000 mm over short distances around the Grasberg, but in general, an average daily precipitation of 10 mm per day applies and leaching of the overburden is continuous throughout the year. Mining commenced in 1988, and almost all of the overburden mined up to 2003 was potentially acid forming. The current acid drainage from this overburden is being collected and treated. From 2004 to the end of the Grasberg pit operation in 2014, approximately 70 per cent of the overburden will be potentially acid forming and 30 per cent limestone. A program of laboratory leach columns, field test pads and an instrumented full-scale dump was developed with the objective of defining scale up factors to quantify the acid and metal leaching rates and to evaluate the stockpile geochemistry and control options. The results of an ongoing seven year program have demonstrated feasible scale up between laboratory columns, field test pads and the trial dump in relation to material geochemistry and ARD evolution trends at Grasberg. The potentially acid forming waste types are highly reactive and maximum acid generation rate occurs within two to three years and that maximum copper release occurs within one to two years of exposure. The results also show that the net acid generation (NAG) test provides a good estimate for the potential acid load from overburden types. The chemistry, temperature and oxygen data from the trial dump suggest that oxidation and acid generation is occurring throughout the dump but at a decreasing mass rate with increasing distance from the toe of the dump. It is apparent that convection and/or advection are important mechanisms for the transport of oxygen into and within the dump. Key results and findings of the investigations carried out are presented and the implications of the findings for long-term ARD management at the Grasberg mine are outlined.

Jan 1, 2003

By Milawarma E, Cusack C

The Sapan Dalam coal deposit of Indonesia consists of ten steeply dipping seams with thicknesses varying between 0.1 and 3.5 m and split by shale, clay, silt and sandstone. The area contains four faults dipping about 75¦ with four to 85 m vertical displacements. The complex nature of the deposit coupled with limited 27 exploration drillholes at an average spacing of 200 m made it difficult to create a realistic geological model. A three-dimensional gridded seam model gave a fair representation of the deposit. Attempt to create an optimum pit using the WHITTLE 3D pit optimiser proved unsuccessful since the pit optimiser is restricted to standard regular or fixed blocks. The gridded seam model was converted to a fixed block model prior to the optimum pit design. Smoothing and pit base controlling were also introduced to obtain a smoother pit. A mining scenario produced 3.6 million tonnes of coal, 28.4 million bcm of waste and US$18.1 million revenue.

Jan 1, 1995

Interpreted geologic domains provide the geologic architecture of many current models used to estimate the potential economic resources in mineral deposits. The spatial extent of each domain is usually defined by a three-dimensional wireframe or triangulated surface.The set of geologic wireframes forming part of a resource model might generally be called a spatial interpretation of some set of geologic features coincident with the mineralisation, based primarily on logged and mapped properties of the samples and other exposures of the mineralisation. The interpreted spatial distribution of rock type, alteration and grade of drill hole samples above a particular grade threshold are commonly used criteria in constructing the geologic domain wireframes. Frequently, the grade threshold is closely related to the anticipated economic cut-off grade. The boundaries or spatial limits of different domains are most commonly defined as æhardÆ or æsoftÆ. A æhardÆ boundary usually means no dependent relationship of any kind is defined between the properties of samples inside a particular domain wireframe and those samples outside the wireframe. A æsoftÆ boundary commonly implies that some kind of dependent relationship does prevail between the properties of samples inside and outside the particular wireframe. Many ways are used to describe those relationships, few of which are based on spatial analysis of the continuity of sample attributes across the domain boundaries. In local estimation procedures such as ordinary block kriging, æhardÆ boundaries act as a total barrier to the influence of samples on either side of the boundary depending on the location of the block being estimated. In some instances, æsemi-permeableÆ boundaries are used in which the samples inside a domain wireframe are allowed to influence the estimates outside but not the reverse. This can lead to many undesirable effects in estimates of block grades.This paper discusses the value of this approach to geologic domaining from a viewpoint of model complexity, as well as in relation to the implications for both linear and non-linear estimation methods and contrasts it with alternatives. It also explores some important consequences of using æhardÆ and æsoftÆ geological boundaries with the commonly used modelling methods: excessive smoothing of estimates near domain boundaries and conditionally biased estimates of grade at the global and local scale.

Sep 26, 2011

Nickel WestÆs Kalgoorlie Nickel Smelter operates three Peirce-Smith converters, each processing 110 tonnes of matte per charge. The vessels are lined with chrome-magnesia refractory with a mouth traditionally constructed from steel liner plates, protected with cast refractory. Mouth refractory is damaged by molten material and the action of cleaning solid buildup off the mouth. Once damage has accumulated, the mouth must be frequently maintained with hot refractory gunning or a mouth leak may occur. Such a leak requires a 32 hour repair period. A converter mouth redesign program was undertaken with the aim of reducing the rate of mouth damage during operation, eliminating mouth leaks and shortening mouth replacement times during vessel rebuild periods. An overview of the redesign process and operational performance is contained herein.

Jan 1, 2005

By Horiszt G

his report is going to point to that the effect of the mining dewatering on the area of Transdanubian Mountain Range has reached a phase when the cost of dewatering and providing damages can seriously jeopardize a profitable mining operation. Up to 60s the interest of mining had been dominant only, but since the begining of 80s the conceptions of industrial development and the value of enviroment protection have been changed. The natural karstwater balance of the TMR can be presented (Figure Land 2.) and the present situation of it points to that the descharge has exceeded the reacharge in 50 %. During the past 10 years the decreasing of the stored karstic water resourches was 1.1 km . The decreasing of the spring yields reached 80-82 % of the natural ones. (Figure 3-4.). Conservation of the present discharge may lead up to the totaly drain of the karstwater regime. A computer aid control system had been to develop by the bauxite mining and using of it the yield of dewatering decreased and a moderate rising of the water table has started since 1986. A recunstruction was made at the biggest thermal-medicinal lake its springs have had their source in 40 meter depth inside a spring cave at the bottom of the lake. Earlier the spring yield decreased due to the dewatering activity of mines. As a result of using of the CAC system and the providing works at the thermal sprino,the karstwater balance has got in the state of equilibrum, the first cost was decreased and spring yield was increased and the enviromental limits were adverted from the way of mining.

Jan 1, 1988

By Rautio V

The mining sector has been automated and robotised very rapidly during the last few decades. The organisation of work, schedules and housing has been modernised from the traditional modes of industrial society toward the more flexible modes of

Jan 1, 1998

Kamhalda is located within the Yilgarn Craton of Western Australia, specifically in the Norseman - Wiluna greenstone belt. Numerous nickel sulphide deposits have been mined at Kambalda with I I mines currently operating. For several years, a program of in-mine geophysics has been operating at Kambalda, with downhole electromagnetics (UHEM) one of the key techniques used. Three case studies illustrating the uses of UHEM in mines are presented here. In the first example, the Helmut South deposit was discovered as the result of an extensional exploration program. The first drill hole in the program intersected ore width and grade mineralisation at around 760 in depth. Two subsequent holes intersected subgrade mineralisation. DHEM surveys were completed in each of these three holes, with anomalies recorded indicating that a large conductor was located directly south of the first hole. The next hole intersected this target, for an intersection of 21.6 in at 3.5 per cent Ni. DHEM continued to play a role as the exploration program proceeded, providing drill hole targeting based on anomalous responses recorded in each drill hole. In the second example from Carnilya Hill, old drill holes were surveyed with DHEM in order to search a large section of prospective contact for massive ore pods. An off-hole anomaly was detected and subsequent mining discovered a small but high-grade pod of ore which was extracted for a considerable profit. Carnilya Hill has limited reserves and discoveries such as this, assist in keeping the mine operating. In the third example from Victor, a program of drilling intersected thin ore profiles in an interpreted flanking position. Without massive ore close by, these intersections probably do not constitute economic mineralisation. DHEM surveys of three holes did not detect any conductors. The area is now regarded as sterilised of significant massive ore and exploration efforts and dollars can be focused in other areas. These three examples demonstrate the type of successes that can he achieved through the use of DHEM.

Jan 1, 1997

By Grieve BL

For a blast to be successful both heave and fragmentation must be satisfactory. Amongst the major factors influencing blasting are rock properties. This paper considers the effect of rock density on fragmentation and heave and how better results can be achieved in dense ore. Patterns which increase the heave and give better fragmentation are examined and the application of theory to the blasting of the Dales Gorge Haematite, density 4.2 - 4.5 t.m.,3 is then discussed. The drilling of staggered patterns instead of square patterns and a shallower 'V' initiation system has given better heave and fragmentation. This practice has re- duced backbreak and improved toe conditions; these factors have resulted in increased load ing rates. There has been an increase in the lump/fine ratio which is consistent with the theory although other factors such as ground conditions could have contributed.

Jan 1, 1978

By Ballantyne GH

The Ladolam gold deposit on Lihir Island, in Papua New Guinea, is a large disseminated gold deposit hosted by hydrothermal breccias. The deposit occurs in the cupola zone of a 350,000 year old monzonite stock which is emplaced in the collapsed caldera of a shosho- nitic stratovolcano.

Jan 1, 1987

The Olympic Dam deposit is located some 600 km north of Adelaide in South Australia. It was discovered in 1975 by Western Mining Corporation and in 1979 a joint venture was formed with British Petroleum for the evaluation and development of the project. Studies were completed and construction started in 1986 with the plant being commissioned progressively between April and August of 1988. In 1993 Western Mining acquired BP's interest and are now owners of the whole deposit. The scale of the initial development was 1.5 Mtpa of ore for the production of 45 000 tpa of copper cathode, 900 tpa of uranium oxide and some gold and silver. Two expansion programs have occurred in 1992 and 1995 and current performance is at the rate of 3 Mtpa of ore for the production of 84 000 tpa of copper cathode, 1500 tpa of uranium oxide, 24 000 oz per year of confined gold and 380 000 oz per year of confined silver (Table 1). An aerial view of the plant is shown in Figure 1. The benefit of diversifying into the production of more than one product is undoubted and the flexibility of being able to produce variable quantities of copper and uranium also allows advantage to be taken of a change in market conditions.

Jan 1, 1996

The three systems of mining in use in the Southern Coalfield of New South Wales are bord and pillar with or without subsequent extrac- tion, longwall and shortwall. Bord and pillar with extraction is regarded as the conventional system. The application of continuous miners and powered roof supports (Shortwall) to coal min- ing has, grown in recent years from something of an oddity among extraction systems to an acceptable and viable approach in certain min- ing environments. The method can be applied in a high proportion of situations where normal pillar extraction is practised with advantages over the conventional approach. These advantages extend to both safety and efficiency aspects and also include better utilization of coal reserves. It holds hope for further gain in efficiency because its simplicity of layout lends itself to achieving the goal of contin- uous haulage towards which operators are always striving.

Jan 1, 1976

The paper describes the reasons for developing, specifically in South Africa, dense medium processes to allow baths to operate at low (about 1,35) and high (about 2,0) cut points. Low density processing was developed to meet the demand for low ash coals; high density processing was developed to enable heavily contaminated raw coals, destined to be burned in captive power stations, to be de-shaled without loss of combustibles. The anticipated and actual technical difficulties of operating baths at such density extremes are described, and the results from operating plants outlined.

Jan 1, 1987

Exposure to respirable contaminants in mine atmospheres has long posed a serious hazard to miners. The control of these hazards, some of which can have sudden and catastrophic effects and some others, slow and long enduring consequences, has been a major concern for labor, management and government alike. This concern has manifested itself in four primary mechanisms of control -- (1) regulatory control through minimum standard setting by the passage of mine health and safety laws, (2) engineering control through design and operation of mines according to the best recommended practices, (3) medical control through periodic physical examinations, wearing personal protection devices, etc., and (4) legal and social control through workmen's compensation laws for occupation related health rleterinratinn_

Jan 1, 1988