Search Documents

By A W. Bewsher, T C. McCu, D B. Mapleson

The Miitel nickel sulfide deposit has been overprinted by a family of late stage structures that have acted as conduits for fluids that have contaminated the orebody with arsenic minerals. This has resulted in highly variable and unpredictable arsenic grades throughout the Miitel orebody. The ore produced from Miitel is processed under a toll-treatment agreement with Western Mining Resources Kambalda Nickel Concentrator. Part of this arrangement includes a financial penalty if monthly average arsenic grades in ore delivered exceed 800 ppm. This constraint has provided an extra challenge to the Miitel mine geologist in addition to daily underground duties. Routine development and stope mapping, close spaced sampling and cross-sectional interpretation were used in building an understanding of the structural controls of arsenic mineralisation and ore repetition at the Miitel nickel mine, and in providing maximum input to mine planning and scheduling. The distribution of structures responsible for arsenic introduction is now well understood from detailed mapping, sampling, and interpretation. By applying these insights to mine scheduling, the operation has successfully managed arsenic levels within the required specifications. Geological mapping has also improved the understanding of the structural complexity of the ore deposit, leading to the addition of ore tonnes and an increased confidence in resource modelling. Regular sampling and tight controls on data quality provided confidence in a strongly skewed arsenic data set. Multiple Indicator Kriging has been used for resource estimation of the arsenic contaminated nickel ore since it allows explicit control of the spatial influence of extreme grades in the positively skewed arsenic sample population. Both the grade control and exploration data sets are used to model the arsenic distribution.

Jan 1, 2003

Segregation studies in ternary systems of glass ballotini, iron ore and coke particles (with size range of 1-8 mm in each) in filling and emptying a laboratory size Paul Wurth hopper are described. In-bin segregation is shown to be a function of the position in the hopper, the nature of the material and the feed composition. The in-bin results are correlated by the equation C = C0k, where C and C0 are the size compositions (wt per cent) in the hopper and feed respectively, and k is an experimentally obtained segregation constant. The results of now pallern measurements show that material discharges from the hopper according to the sequence; core now - wall now - scaffold now, where the latter represents stagnant material at the hopper wall that discharges last. Size segregation in the discharge stream from the hopper is shown to be a function of in-bin segregation and hopper now pallern. A method of predicting discharge segregation from these two sets of data is suggested. The results of the model studies are also compared with industrial data and these show satisfactory agreement. Discussion of the hitherto ignored effect of size segregation on hopper now rates, stoppages and other operating problems is also included.

Jan 1, 1985

By Rigby D, Gould K. W, Hart G. H

The variation in chemical and isotopic composition of hydrocarbon gases generated from humic source rocks in the Cooper Basin, the orth West Shelf, the agoorin oil shale deposit. ollinsville and the southern Sydney Basin is reviewed, discussed and interpreted.The primary composition of gases generated in and released from such source rocks appears to be very largely controlled by the degree of dispersion of the organic material. For example in eoaly shales, where the degree of dispersion may be high, products as generated may escape into surrounding inorganic structures where further maturational reactions may proceed. On the other hand, when the organic materials occur in massive form, as in coal seams, the hydrocarbons generated tend to be retained within the coal. Further cracking to the stage of methane generation is usually required before release of hydrocarbon products is significant.Secondary factors of importance in determining seam gas composition in the Bowen (Collinsville) and southern Sydney Basins are the invasion of coal measures by carbon dioxide from external magmatic sources and/or the vertical diffusion and loss from the surface ofgases generated at depth.Isotopic measurements of gas composition have been particularly valuable in determining the origins and histories of the gases examined, in demonstrating when gases are of mixed origins and in the prediction of gas quality in exploration.

Jan 1, 1985

By S Wotherspoon

At Kalgoorlie Consolidated Gold MineÆs (KCGMÆs) Fimiston Operations, located on the periphery of Kalgoorlie Boulder in Western Australia, roughly 7.5 million tonnes of rock are broken each month for the extraction of gold. With the close proximity of neighbours to the mining operations in the Chaffers Cut Back, special blasting techniques and tools were employed by KCGM to manage the blast induced vibrations and noise in this area. The i-konTM initiation system coupled with OricaÆs complementary modelling and analysis tools offered the complete blast management package. With these tools KCGM management and Orica Mining Services commenced an investigation into the benefits of electronic initiation. Prior to the commencement of electronic blasting, initial modelling was conducted to examine the vibration time waveforms and their frequency content, as these were expected to have an impact on vibration interaction with structures such as large buildings and urban dwellings. This work looked at results measured for a previous conventionally (pyrotechnic) initiated blast in the area and compared it to the results obtained when the blast was modelled with electronic initiation and faster timings. The predicted peak particle velocity (PPV) and structural vibration factor (SVF) were calculated. From the results it was concluded that the investigation into using i-konTM electronic initiation system and SHOTPlus«-i blast design software had some real potential to improve blast vibration management on the cut back. The use of the electronic initiation system and complementary software allows intricate timing designs to be accurately placed into blasts. The system has a number of working modes that allow either the precise design timings to be logged automatically into each detonator or to be manually logged where a variation from the design exists. Where such variations from the design occur, the electronic system permits the actual timings used to be uploaded back into the design file. This allows both design and real actual timings to be stored for future analysis or reference.

Jan 1, 2004

By Jones M

The concept of precise, accurate timing with Electronic Delay Detonators (EDDs) was first seriously addressed in the mid-1980s and much was made of the cheapness and profusion of digital watches in terms of the likelihood of EDDs also being cheap and easy to produce. Ten years later, with every major explosives company and many electronics groups having instituted projects to capitalise on the promise of these devices, production devices are still to come into general use. In South Africa, Expert Explosives units have been used in most applications during proving trials and more recently for production blasting in underground ring stoping and open cast coal. The outcome has been valuable learning both as to the benefits and technical requirements for electronic delay blasting, and especially, safety aspects. Examples are shown of production blasts which utilised the power of EDDs. It is evident that it is not delay accuracy alone which determines the value of these systems, but the whole robustness, flexibility and ease of delay allocation when harnessing blast engineering knowledge. Muckpile movement and shape, fragmentation and vibration frequencies have shown to be greatly influenced by designs which can be implemented no other way. The flexibility of a system and the power of the software controlling it are crucial in capitalising on blasting potential, which lies in integrating control of blast timing with other developing electronic Technologies.

Jan 1, 1995

The gossan developed from the Whim Creek Cu-Zn-Pb-Ag sulphide deposit, in the Pilbara region of Western Australia, occurs near the top of a ridge in a dissected plateau 01 moderate relief. The gossan is characterized by the abundance of secondary ore minerals which indicates that it is relatively immature, due to climatic conditions and erosional stripping.The abundant presence of secondary carbonates indicates that the low pH generally resulting from sulphide oxidation has been neutralized, probably by the buffering effect of carbonatcs and silicates. Fe, Cu, Pb, 'Ag and Sn have been enriched in the gossan relative to the primary ore, and Mn, Ti, Co and Ni have been strongly depleted; other elements have remained substantially unchanged. The gossan has a strong gcochemical signature characterized by high Cu, Zn, Pb, As, Sb, Sn, Ag and Mo coutents. Boxwork textures are poorly developed, bu't the gossan has other diagnostic mineralogical features including sulphide inclusions in quartz and the presence of residual cassiterite.

Jan 1, 1982

Economic conditions dictated the lead time from concept to commissioning of the Kambalda C.I.P. Plant. The high gold price prevailing at the time the Victory ore-body was discovered provided the impetus to establish a treatment plant with the utmost haste. Consequently only limited metallurgical testing was possible. Fortunately the Kambalda Metallurgical Department had experienced gold metallurgists among its' staff. This enabled a rapid assessment to be made of the ore types to be treated. Flexibility was the keynote in the plant design. Overseas practice and experience was drawn upon extensively, but it was known that problems uniquE to the Kambalda Plant would be encountered due to the high nickel content of the C.I.P. Plant feed and the difficult clays in some of the areas. These fears were well founded and problems have been experienced. However the plant design has enabled these problems to be absorbed, if not overcome, and design production rates were achieved and maintained within three month; of start-up.

Jan 1, 1982

By Stanley I. M, Brett D, Dickson R

The Mt Lyell Mine, situated in Queenstown on the west coast of Tasmania, has a production history of more than 100 years. Previous mining activities have resulted in substantial modifications to environmental conditions at Mt Lyell and disposal of sulphidic waste rock across the lease has left a legacy of on-going environmental impacts including acid drainage (AD). In 1995 Copper Mines of Tasmania (CMT) was granted a mining lease Irons the Tasmanian State Government for redevelopment of Mt Lyell and indemnity from actions concerning pollution from previous occupation and use of leased land. The Environmental Management Plan (EMP) for the Mt Lyell redevelopment committed CMT to be responsible for waste rock dumps generated from their activities and to ensure that management is in-line with best practice environmental management principles. CMT commenced commercial production in December 1995 with sulphidic material from development of the underground Prince Lyell mine reporting to a single waste rock dump constructed according to a management plan developed in July 1995 and superseded by a management plan for extension in May 1997. The CMT waste rock dump currently has a total capacity of 220 000 m- and approximately 120 000 m3 of rock have been placed to-date. Material reporting to the dump is placed in a densely compacted state to a controlled surface profile. The dump is clay capped and a final revegetated soil layer placed on top. A rock pitched drain extends down to a wetland area in order to remove stormwater and minimise possible soil erosion on the revegetated sections. An integral part of the management plan for the waste rock dump involves characterisation of waste rock to identify geochemical rock types according to acid forming potential with provision for selective placement within the dump. High-risk materials are selectively placed and covered within the core of the waste rock dump, where possible, to control sulphide oxidation. Monitoring equipment has been installed in the waste rock dump by the Australian Nuclear Science and Technology Organisation (ANSTO) and an on-going monitoring program has been established to demonstrate the integrity of the dump cover as a barrier to the influx of atmospheric oxygen into the dump. The overall objectives of this program of work are to control the oxidation of sulphidic waste rock in the waste rock dump, minimise the risk of AD, prevent pollution of the aquatic environment and thereby demonstrate the integrity of the CMT waste rock dump management Strategy.

Jan 1, 1997

Underground mining in the West Moreton coal field started in the 1870's. Subsidence related to coal mining activities is an ongoing problem facing planners and developers in the Ipswich area in South Eastern Queensland. The history of coal mining in the area over the last 110 years has left the legacy of periodic surface instability in several areas. In general, modern engineering analysis with current mining methods combine to create predicatable analysis of surface stability and movement. Where old workings using several variations of the bord and pillar system are affected by current activity, the predictibility of the surface movement is greatly reduced. Geological complexities further complicate the analysis. Mining and the related dewatering affects the stresses on pillars in old workings. This is caused by reducing buoyancy effects caused by changes in the water levels in old workings. Of particular relevance is the depth of workings and strength of the coal and overburden. The type of subsidence affecting the surface can range from localised pillar failure, to roof failure and potholing and the likelihood of the particular form of subsidence can be assessed from studying the workings in relation to the stratigraphy and structure of the coal measure Formations.

Jan 1, 1988

The selection of the ore haulage system is one of the most crucial decisions made in the development of an underground mining project. The haulage system is, once selected, one of the components of a mine that defines its ability to respond to changes in mining inventory and the market conditions for its products. Over the last decade, in Australia at least, this selection process has largely centred on the debate over the merits of shaft and decline truck haulage. Little attention, if any, was given to the application of inclined conveyor haulage as a real alternative to the shaft and truck haulage. This is despite well established precedents for its application in the underground coal industry and some limited applications in underground metalliferous mines. This paper seeks to explore the case for the application of inclined conveyors as a legitimate ore haulage system for underground mines. The case for conveyor haulage is illustrated by an overview of the application of conveyors at some existing operations, and discussion of what conveyors have to offer as a mine haulage system and the issues that are associated with them. Material drawn from the feasibility studies for NewcrestÆs Ridgeway mine and Telfer Deeps Project is presented as case studies that considered selection of inclined conveyor haulage. The purpose of these case studies is to highlight the value of impartially approaching tasks of this type with a robust plan. This plan should be able to respond to issues identified as the task progresses towards the objective of finding the right solution for an ore haulage system.

Jan 1, 2005

By Alwan M

At Binebase mineralisation is hosted within an andesitic Neogene volcaniclastic succession on Sangihe Island, Indonesia. Two major alteration types occur; an initial widespread phyllic assemblage of quartz -illite with chlorite, smectite, gypsum and pyrite, and a superimposed quartz - barite - sulphide assemblage. The phyllic alteration arose from a neutral to weakly acidic hydrothermal solution of greater than 200 degrees C, and the quartz - barite - sulphide assemblage arose from a cooler slightly more acidic fluid. This second alteration event is interpreted to have selectively replaced permeable volcaniclastic breccias and coarse lithic tuffs within the altered sequence. Gold and silver mineralisation is associated with the latter alteration, and is locally controlled by the degree of silicification and sulphide abundance. The sulphides present are pyrite, covellite and chalcopyrite. The sulphides are very fine grained with colloform and framboidal textures and were deposited contemporaneously with the bulk silicification of the coarse sediments. A large portion of the mineralised rock has been oxidised to a quartz - barite -limonite - goethite - jarosite assemblage.Coincident gold, silver and antimony geochemical soil anomalies gave the best correlation with anomalous gold and silver grades in bedrock as identified by drilling. Resistivity proved a reliable geophysical method for delineating zones of silicification.

Jan 1, 1990

Water retention, water loss and delay in tailings storage rehabilitation are major challenges for many Coal Mines. Work by Stewart, Backer and Busch in the early 1980s suggested that there were improvements to be made in tailings dewatering and density by the addition of flocculant. This prompted ACARP, in cooperation with Bulga Coal Management (Xstrata), to initiate a research project investigating the impact of flocculant addition on tailings deposition density, water retention and the tendency for tailings to form surface crusts suitable for subsequent rehabilitation. A polyacrylamide-based flocculant (200 - 250 g/tds) was injected into the tailings line immediately prior to disposal into the impoundment area. The flocculated slurry rapidly released clear water and created a beach due to the immediate increase in deposition density. The deposition density increased from 35 per cent w/w to 61 per cent w/w solids within 24 hours and continued to increase to 75 per cent, seven days after treatment. The water capture at the tailings storage facility improved by more than 90 per cent; water which would otherwise be lost from the circuit through retention and evaporation. The impoundment capacity had nearly tripled due to the improvement in initial deposition density from 420 kg/m3 up to 1163 kg/m3. Four weeks after disposal surface crusts were forming on the storage facility, suggesting that there would be less delay between cessation and tailings storage rehabilitation.

Jan 1, 2008

By May P. M

The role of chemical speciation in alkaline cyanide solutions is discussed by reference to recent experimental data from the authors' laboratories. It is shown that serious gaps exist in our present knowledge of the thermodynamics of cyanide complexes in solution. Nevertheless, using the available data and the JESS suite of computer programs it has been possible to develop a simplified chemical speciation model for alkaline cyanide solutions under conditions relevant to the gold extraction process. Some possible implications of the model for plant operations are Discussed.

Jan 1, 1991

By Amanatidis A

In this paper, the kinetics of iron precipitation as sodium jarosite from aqueous solution is investigated. The determination of the reaction mechanism is attempted based on the experimental data of iron removal as a function of time, without using the characteristics of the precipitate.Experiments at the temperature range from 50° to 95°C were carried out with initial conditions of iron concentration IQ g/L, sodium sulphate concentration 25.44 g/L, sulphuric acid concentration 3.68 g/L, pH = 1.5 and agitation rate 600 rpm. Temperature greatly and positively influences iron precipitation from the solution and this is accompanied by pH decrease. The activation energy was determined using the maximum values of the precipitation rate, which were evaluated by polynomial fitting of the sigmoidal shape experimental curves, and it was found to be 44.37 kcallmole. The determination of the rate-controll ing mechanism was based on some criteria used for the discrimination among the three probable mechanisms of precipitation (diffusion, mononuclear nucleation, polynuclear nucleation). These criteria utilise various funetions of the recovery 'a' of iron precipitated versus time, the most important of which are the chronomals. The results of the kinetic analysis procedure showed that the polynuclear nucleation growth mechanism controls the precipitation of iron as sodium jarosite. This was confirmed by the high value of activation energy, excluding diffusion as the controlling mechanism.

Jan 1, 1993

The Honeymoon Well nickel sulphide deposits are located in the Agnew-Wiluna greenstone belt, about 45 km south of Wiluna. Both disseminated and massive sulphide nickel deposits are hosted by komatiitic rocks within the deformed and metamorphosed Honeymoon Well ultramafic complex. Fresh ultramafic bedrock is covered by up to 50 m of highly conductive transported material which greatly hampers both exploration and understanding of the bedrock geology. In the early-1970s, mineralisation was discovered by diamond drilling geochemical anomalies defined by wide-spaced percussion drilling over ultramafics that had been outlined by ground magnetics. Subsequent drilling has defined a resource of 158 Mt at 0.71 per cent nickel (based on 0.4 per cent nickel cut-off, 300 m below surface, December 1995) in four deposits. Over the life of the project a wide range of geophysical techniques have been used including airborne and ground magnetics, time domain clectromagnetics (EM), induced polarisation (IP)/resistivity, gravity and downhole techniques including EM, IP and physical property Measurements.

Jan 1, 1996

By Boger D. V

Two industrial case studies in which detailed investigation of the flow behaviour of mineral slurries is used to assess the feasibility of pipeline solid transport are described. The first example deals with the pumping of highly concentrated bauxite tailings to disposal, while the second exam- ple examines the possibility of transporting high-density Victorian brown coal slurries which previously has been thought as uneconomical. It is demonstrated that these typical solid handling problems can be solved by a good understanding of the rheology of suspensions.

Jan 1, 1989

By Wright J. K

In recent years the production of steel from directly reduced iron ore pellets has ex- panded rapidly. However continued growth will depend on an adequate supply of suitable raw materials for the various commercial gaseous and solid reductant processes now in operation. Al- though at present Australia does not produce pellets primarily for direct reduction, there is an increasing awareness of Australia's potential role as a supplier of high grade ores for export and/or domestic use. The properties and quality requirements of iron ore pellets made specifically for directre- duction (DR) are reviewed and the laboratory techniques and test methods used at the CSIRO Division of Process Technology for the evaluat- ion of potential DR feedstocks are described. At the present time most of the evaluation tests for DR pellets are extensions of those de- signed for existing blast furnace (BF) burdens. In the case of some physical parameters such as cold compression strength, abrasion index and cold strength after reduction this extension is quite satisfactory. In the measurement of para- meters such as reducibility, swelling and stick- ing tendency, however, it is necessary to deve- lop meaningful standardized tests so that ores and pellets can be ranked for DR performance. To do this, data from the laboratory tests and from operating plants must be correlated.

Jan 1, 1980

By Reed M. E, Cloutt B

Particulate samples were taken from the gas space in the settler of the Kalgoorlie nickel smelter using a vertical sampling probe and a specially designed isokinetic sampling probe which also quenched the samples. The vertical sampler was found to give unrepresentative samples. Suction thermocouple measurements of the gas temperature were also made. Using the isokinetic probe samples were taken at four points ranging from near the base of the reaction shaft to the base of the uptake at depths up to 1.5 m into the settler. Dust loadings and the sizing of the samples were determined. These parameters were found to be most affected by sample position and depth. The dust loading decreased along the settler but increased with depth. The loadings varied from zero near the roof to several hundred g Nm 3 near the slag. The dust also became coarser with increasing depth into the settler. Examination of the samples showed them to consist of spherical particles the largest of which were about 500 microns in diameter. The dust was mainly composed of mixed iron/nickel oxides with a little sulphide.

Jan 1, 1991

By Hagan T. O

The problem of rockbursts presents a serious threat to many deep, hard-rock mines. For several decades, the owners and managers of affected mines have been concious of the urgent need to control rockbursts but, to a large extent, their efforts have been hampered by a lack of fundamental knowledge. This paper will attempt to outline the extent and depth of present understanding of the phenomenon and to show how better control may be achieved in the future. It is suggested that it is helpful to distinguish two aspects of the problem: that pertaining to the mechanism of the seismic event and that associated with the mechanism of damage. Understanding damage mechanism will enable development of better support techniques while proper understanding of the source mechanism could lead to better mine planning and improved stoping layouts. In this regard, the practice of partial extraction with systematic strike stabilising pillars is discussed in some detail.

Jan 1, 1986

Bureau of Medical Inspection, Broken Hill, New South Wales.INTRODUCTIONFor a considerable time it has be3n realised that the pathological changes produced in human lungs by the inhalation of free silica varied, not only according to the amount of silica inhaled, its particle size and the period during which it was inhaled, but also according to other mineral elements which might be admixed with the fine silica dust and inhaled along with it, or inhaled subsequently to the silica containing dust. It was observed that, in many instances, these admixed dusts tended to inhibit the action of the free silica in causing injury to the lungs, as well as the development of certain complications, whilst in other cases it was felt that certain substances could actually accelerate the tissue damage caused by the silica.A fresh impetus to the problem of the prevention of the development of silicosis was given when, in 1937 and 1939, Denny, Robson and Irwin published papers entitled "The Prevention of Silicosis by Metallic Aluminum." Working at the same time at the Saranac La.boratory, and quite independently, and using a colloidal aluminum hydroxide, Gardner arrived at the same conclusions as Denny, Robson and Irwin, namely, that in experimental animals the development of silicotic changes could be prevented if eithertogether with the silica, or subsequent to its inhalation...

Jan 1, 1946