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By M Littlefair, D Gribble, R Rounsley, I Te

Low-density explosives (LDE) have applications where the explosive properties of ANFO are not well matched to the rock. In particular, rocks that are of low strength and/or well fragmented in situ. Dyno Nobel Asia Pacific (DNAP) has developed a new LDE, BlastLiteTM, which can be used as a cost-effective replacement for ANFO with excellent detonation characteristics. The product is based on ANFO with the addition of a bulking agent. The key to the product lies in the ability of the bulking agent to form a homogeneous blend with ANFO without the need for any emulsion matrix to bind the product together. This results in an LDE of low cost and high weight strength compared to existing commercial LDE products. The product has been trialled extensively and has proven to provide results that are equivalent to, and often better than, ANFO with reduced powder factors. This paper details the laboratory development and results of field trials for DNAPÆs LDE solution: BlastLite.

Jan 1, 2004

By Nilsson C

Man has always been and will always be part of his environment, in ,a good, bad or indifferent manner. Until quite recently, this environment has been the atmospheric boundary layer above the land masses, and to a limited extent the air-sea interface of the oceans. Since the days when he lived in caves, he has built up a wealth of observations on these two environments,-with ever-increasing scientific precision which unfortunately until quite recently was completely insufficient for modern capabilities of data analysis. Consequently, in a sense, he has left in his wake thousands of years of missed, opportunities for making exact observations and increasing his understanding. The data of the past are lost and he has to be satisfied with what he can assemble from now on when his environ- ment, largely as a result of his actions, is exhibiting more and more rapid variations in time; in other words, time series of observations of phenomena are required, the length of which is critical for most purposes of analysis.

Jan 1, 1970

The Auscoke project has reached-a stage where a pilot plant nominally able to produce 100 t.p.d. of coked briquettes is being brought on stream during Nov. 1971 . The targets for this stage of the project are to establish the technological and economic value of Auscoke for the iron blast furnace, and to verify the commercial feasibility of large scale plants. The project originated at the B.H.P. Central Research Laboratories (C.R.L.) and work to date has shown that using a two stage contin- uous process, strong large coke can be produced at good productivities from medium or low volatile poorly caking coals. General features of the pilot plant and processing are discussed.

Jan 1, 1972

Knowledge of the hydrogeological setting of a mine forms an integral part of a mining operation. Groundwater impacts, initially, on mine feasibility. Then, on commencement of mining, it interacts on the operational components of dewatering, water supply, tailings leachates, mine wall stability, stormwater run-off, water disposal, impact on regional environment and mine closure planning. The recording of hydrogeological information is frequently overlooked during resource and reserve definition as well as during the course of mining when prime opportunity exists for the collection and collation of this data. In recent times, the exclusion of hydrogeological data has been exacerbated by use of high air pressure drill rigs that exclude water inflow. The recording of water data has been further inhibited by the use of computer coded drill logs that do not include the site geologistÆs or drillerÆs comments on drilling problems and observations associated with groundwater intersections. Geologists now infrequently directly supervise drill rigs, but visit the rig only intermittently to evaluate drilling progress. They do not see first hand drill performance characteristics at water make zones. Drill cuttings, as drill chips and cores, are now mostly logged away from the drill site so that wet sample locations, visual water flow evidence and verbal comments from the driller are not recorded. As a result, mine geologists now do not direct adequate attention to the delineation of lithologies and structures that store and transmit water. This paper provides examples of water sighting and recording techniques applicable to a mining operation. Examples are also provided where hydrogeological conditions have been disregarded with serious impact on the progress of mining. The recording of hydrogeological data should be maintained and formatted by the site geologists into a useful database for review as and when required by specialists in hydrogeology, geotechnical and mining engineering and the environment. The information can be coded by the site geologist for inclusion into the mine database. A groundwater dataset, compiled during the progress of field investigations, will save the considerable cost of re-drilling and hole re-entry testing which would otherwise be required to provide base level hydrogeological information required for progress of mining. Apart from working mine use, a hydrogeological dataset is a necessary component for planning mining closure and mine legacy conditions.

Jan 1, 2003

The Blackwater Coal Mine is a modern open cut operation using large draglines for over- :)urden removal and shovels, loaders and trucks to mine and haul coal to the crushing and coal ?reparation plant. Operations at the mine are described in sequence following through overburden removal to the railing of product coal from the mine site. The close operating connection between the mine and washery, which results from the blending of raw coal into clean product via the qashplant bypass system, is stressed. Some features of special interest at Blackwater Mine, such as land reclamation and slope stability,are outlined.

Jan 1, 1974

Methane is present in varying degrees in nearly all underground coal mining operations. At mixtures with air near 5-15% it is explosive and consequently since it is not usual for these levels of contamination to be reached in the general body of a mine ventilation system it is not unusual to experience it in specific places. On longwall faces the most used power loader is the shearer machine and because of its general shape, situation and operation it is likely that all the factors which are required to cause a frictional ignition can be present. This paper makes a general appreciation of the causes of these ignitions and methods which are and have been used to control these situations on and around these machines.

Jan 1, 1981

During the life of a mining project in Papua New Guinea (PNG), the greatest impact is on the people of the project area and the most intense, day-to-day contact is between these people and the project's field staff. Yet formal structures at present emphasise contact between much higher levels of national government and company personnel. Whilst understandable, this is unfortunate particularly since, given the nature of PNG politics, villagers do have a powerful influence on project success, as recent dramatic events on Bougainville have indicated. A greater role for local views and greater attention to such views by other parties is clearly required. But to achieve a successful marriage between informal village politics and the formal structures of investment procedures will require considerable patience and adjustment. This should be reflected in the cost of project development and be regarded as being as of a significance equal to that currently accorded to the technical aspects of project development.

Jan 1, 1990

Deposition of uranium in the South Alligator river area has been influenced structurally by reverse faulting; and lithologically by carbonaceous shales and sandstones. Mineral assemblages suggest a mesothermal-epithermal epigenetic mode of origin. The ultimate source of the uranium and associated metals is probably in deep seated magmatism which is expressed at surface in the widespread penecontemporaneous vulcanity.

Jan 1, 1968

By Rospigliosi RT, Krouse HR

The San Vicente stratabound zinc-lead rhythmite deposit, Peru, is hosted in carbonates of the Late Triassic - Early Jurassic Pucara Group. These strata were deposited in a large, shallow water, carbonate platform which extended nearly continuously for 150 kilometers (north-south) in the eastern part of the Pucara basin.The distinctive sulfide-bearing rhythmites occur in three dolomite units which, from bottom to top, include the San Judas horizon with one sulfide-bearing manto; the San Vicente horizon with seven sulfide-bearing mantos including the main ore horizon; and the Alfonso horizon with three sulfide-bearing mantos. The dark gray sulfide-bearing dolostone layers range in thickness from a few millimeters to a few centimeters and contain variable amounts of carbonaceous material, pyrite, quartz, fine-grained sphalerite and galena. They are bordered on each side by selvages of yellow to red-brown coarse-grained sphalerite containing minor amounts of galena. Coarsely crystalline white or gray sparry dolomite is found between the coarse-grained sphalerite layers. Although commonly stratiform and uniform in thickness, the dark layers curve, "pinch out," coalesce, and form "islands" and "peninsulas."Mineral replacement textures, the paragenetic sequence, and presence of sparry dolomite, bitumen, intraformational breccias and isotope data support a hydrothermal replacement origin by metal-bearing solutions that deposited the ore and related minerals in space previously occupied by dolomite and evaporite minerals. The alignment of the Zn -Pb deposits, and at San Vicente the orientation of the mantos, the spatially and temporally associated igneous sills and the tourmaline-bearing sandstone support hydrothermal mineralization driven by a magmatic heat source in a tensional regime.

Jan 1, 1990

By Large RR

Precious metals in the Rosebery north-end orebody occur predominantly in sphalerite- galena-pyrite ore and to a lesser extent in massive barite mineralisation. Gold may also occur in the upper parts of pyrite-chalcopyrite ore (although this ore type is usually gold poor), in pyritic mineralisation lateral to base metal sulphide lenses and in the footwall (very patchy). Although present, remobilised precious metals do not occur in economically significant quantities. Mineralogically, silver occurs dominantly in tetrahedrite and, to a lesser extent, argen- tiferous galena. Gold occurs as electrum associated dominantly with pyrite and, to a lesser extent, tetrahedrite. Geochemical modelling suggests that silver was probably transported as a chlorocomplex, while gold was transported dominantly as a thiocomplex, although at high temperature gold was transported as a chlorocomplex.

Jan 1, 1987

By Jensen B, Ofori P, He Y, White E, Stanmore B, Brien M, O&apos

As part of a large AMIRA project, an on-line moisture meter was installed at two mine sites in Central Queensland. This project investigated the factors which control the moisture content of coarse (>0.5 mm) coal from the centrifuges used in conventional coal preparation plants. It was placed immediately after the first centrifuge to isolate the factors pertaining to one machine and its feed.The meter was found to be accurate and precise when compared with manual and mechanical sampling methods. The Grubbs estimator technique indicated that its precision is better than 0.3 per cent at the 95 per cent confidence limit.It has been identified that:1. the variability of the measured moisture contents of coarse coal can be described by normal distributions. Standard deviations of about 0.6 per cent are common; and2. the treatment of the coarse coal on the drain and rinse screens immediately prior to the centrifuge can affect the final moisture content.

Jan 1, 1995

By Lee RJ

A significant basemetal province is recognised in the southern part of the Bonaparte Basin, Western Australia. Epigenetic stratabound carbonate hosted Pb-Ag-Zn mineral- isation occurs in dolomites of Tournasian age within a marginal marine transgressive carbonate and fine grained clastic sequence, spatially overlying the lagoonal facies of a Late Devonian reef complex. The deposits comprise coarse grained sulphide mineralisation characterised by high Pb:Zn ratios (10:1) and high silver (50 g/t) content. They occur at shallow depth, are flat to moderately dipping, and form a discontinuous mineralised trend at the margin of the Sorby Platform, which flanks a Precambrian basement high. Host rocks are predominantly sedimentary breccias and dolomitised footwall carbonates associated with a significant local unconformity transgressed by a siltstone cap rock sequence. The deposits are structurally related to synsedimentary growth faults, local basement highs and tensional en-echelon breccia systems. Fluid inclusion studies have concluded that mineralisation was deposited from a low temperature (85¦C-115¦C) saline ore forming solution. Lead isotope work reveals a Precambrian genetic source of the lead. Locally remnant textures after sulphates are recognised within the host sequence together with common bitumen and oil shows. Reduction of sulphate to H2S was possibly facilitated by either bacteria. activity, or by residual hydrocarbons which acted as a reducing agent. An alternative source of H2S may have been afforded by the thermal degradation of hydrocarbons. A 'mixing' genetic model is proposed for the mineralisation, which conceives the expulsion of metal enriched basinal brines followed by their precipitation as sulphides after mixing with locally derived reduced sulphur solutions at relatively shallow depths in their structural/stratigraphic sites of ore deposition.

Jan 1, 1986

Willemite mineralization was discovered in 1966 in the North Flinders Ranges of South Australia, in the course of a stream sediment sampling programme. Further work outlined a total of nine separate willemite occurrences in the Copley/Beltana area, and ten small deposits in the Toondana area south of Parachilna. Mineable reserves of 1 000 000 tonnes grading 36.8% zinc were outlined in three deposits in the Copley/Beltana area and campaign mining of the Main Orebody commenced early in 1974. The main group of deposits all occurred within red, dolomitized Cambrian Ajax Limestone, and most are associated with significant thrust faulting. The area of the Main Orebody group of deposits has been intensely fractured, and the surrounding dolomites are often brecciated and contain up to 5% zinc. Lead and arsenic mineralization are minor components of the main group of deposits. Masses of Middle Proterozoic Willouran Formation crop out adjacent to or close to most of the deposits in the Copley/Beltana area. The Willouran is frequently highly sheared, brecciated, and often contains large inclusions of younger formations. It is believed that most of the Willouran outcrops represent piercement structures.

Jan 1, 1975

By Raymond G. F

Geostatistics - a tool used by geologists and mine planning engineers to estimate grades and rapidly evaluate alternative mining strategies has reached an advanced stage of development for the silver-lead-zinc orebodies at Isa and Hilton Mines. Geostatistics has been used for over a decade in the massive copper orebodies but the stratiform lead-zinc orebodies are much more complex and provided a completely different set of challenges. Recent increases in computer processing speed and power provided by the Integrated Mine Planning System (IMPS) has aided the development of the geostatistics package. Also the formation of a project team and the subsequent in-house development which has drawn together the expertise of geologists, engineers and system analysts has contributed significantly to the success of the project.The most important feature of any approach to modelling the lead-zinc orebodies is that the kriging search must consider estimate and sample points according to their positions relative to bedding surfaces. By transforming co-ordinates as perpendicular offsets from a plane representing the local strike and dip, it is possible to elongate the ellipsoidal influence to parallel bedding. By interactively modelling surfaces using CAD facilities and then specifying these surfaces as 'hard' or 'soft' boundaries, the geologist has complete control over the kriging process.

Jan 1, 1993

By Bennet A. G

An overall review of the selection of rock strength and deformation characteris- tics for the design of the Melbourne Under- qround Rail Loop (MIJRL) rock tunnels is presented. Particular emphasis is placed on aspects of in-situ testing, including large diameter plate bearing tests. Material on the interpretation of test results for use in the design of the tunnel linings and openings is included, with a brief discus- sion of desiqn methods.

Jan 1, 1981

The Manto Verde copper mine (Atacama Region, Chile) is due to go into production in 1996. It will produce 40 000 tonne/year of copper cathode by heap leaching/SX-EW. Mineralogical studies were undertaken in conjunction with the metallurgical testwork program to characterise the ore and its response to leaching by dilute sulphuric acid. The leachable copper mineralogy is dominated by the oxide copper minerals: brochantite and malachite with minor chrysocolla and atacamite. The gangue minerals include abundant orthoclase, specularite, quartz and chlorite with minor muscovite and trace smectite clay, calcite and limonite. The study showed that complete or partial decomposition of calcite, chlorite, smectite and wad consumed acid and generated solution impurities (Ca2+, Fe2+, Mg2+, A13+, K+, Si4+ and Mn4+2+ ). Although these were manageable at Manto Verde, their uncontrolled build-up could have affected the operation in several ways: the degradation of heap penneability and fonnation of crud in the SX plant from the precipitation of gypsum, goethite, colloidal silica and jarosite; and the entrainment of contaminated pregnant leach solution in the SX organic resulting in the transfer of impurities to the electrolyte and subsequent effects on cathode quality and electrowinning efficiency. In conclusion, process mineralogy played an important role in understanding and managing potential mineral-related problems in the heap leaching and SX-EW recovery of Manto Verde ore.

Jan 1, 1994

Brunswick Mining and Smelting Corporation Limited operates a large base metal property near Bathurst, New Brunswick in eastern Canada. Nominal capacity for the underground mining operation and concentrator is 10 250 DMT/day. Four concentrates are produced by differential flotation technology to recover minerals containing copper, lead, zinc and silver. Two characteristics of the Brunswick ores have a major impact on mineral processing operations. The mineralogy of the ore is complex with a total sulphide mineral content of 85 per cent. In addition, the ore is extremely fine-grained, and satisfactory liberation is difficult to achieve. These characteristics directly influence flotation selectivity and thereby affect metallurgical performance. Significant improvements in metallurgical performance have been achieved through the application of basic grinding and flotation principles using conventional milling equipment. Current operating practice and the metallurgical advancements are detailed.

Jan 1, 1993

It has been clearly demonstrated in both the first, as well as in the last world conflict, that a nation's ability to wage as well as win a war is primarily a function of its industrial, and particularly its steel making capacity, provided both are directed to munition production.The Axis gambled on their pre-war policy of bullets before butter giving them sufficient initial advantage to decide the issue before the Allies had time to gear their industries to war production.Fortunately for us, Hitler and his advisers apparently underestimated Russia's war potential, although they must have known that Russia was, in 1939, the third largest steel making country in the world, as shown by the following figures:

Jan 1, 1947

By Cleghorn JH

Underground mining operations on Kalgoorlie's Golden Mile were suspended in 1976, suffering the combined effects of low gold prices and grades. A subsequent substantial increase in the gold price led to the decision by Kalgoorlie Mining Associates to reopen their mines in 1979. The two shafts selected for access required excessive maintenance. The geological assessment and development parameters prescribed have been successfully used to establish reserves to maintain production at a 390 000 tonnes per annum rate. While ore reserve grade is being maintained from primary stoping sources, supplementary lower grade ore is drawn from remnant pillars and stopes at lower cost.Performance by the workforce has reached levels previously attained and a record tonnage was hoisted in the fourth year after recommencement.Keywords : Golden Mile lodes, geological research, payruns, cut and fill, mill holes, gold price, ore grade, amalgamation.

Jan 1, 1984

By Otuonye F

An outburst is the spontaneous ejection of pulverized coal and gas from the working face in an underground mine. It is caused by overstressing the rock, due predominantly to the influence of geological structures on in situ stresses, stress concentration from the excavation and overburden load on mine openings, and large volumes of gas sorbed in the rock. The spontaneous release of high pressure gas creates intense shock waves which may cause damage to the mine ven- tilation system and the pulverized rock/coal ejected may cause injury or death to miners. The gases emitted pollute the mine air and may also result in death to miners.

Jan 1, 1988