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The problems associated with achieving adequate accuracy for on-site axial flow fan performance measurements are discussed. The ability to test accurately rests heavily on equipment and installation design detail.Aerodynamic performance trials frequently cannot be carried out due mainly to the poor standard of installation design. In a majority of cases this results in unsteady, non-uniform inlet flow conditions to the fan. Details of installation design features and instrumentation, necessary for successful testing, are given for different types of installations and methods of testing. These cover both conventional practice, and new innovations which can provide solutions to difficult problems. Quantitative aspects of flow measurement are considered for various fan and duct configurations.Although the main emphasis is on large primary mine ventilation units which require on-site testing, the principles outlined have wide application to many other types of fan installation.

Jan 1, 1973

Victorian brown coals occur in massive deposits, the quality of which is determined in the first instance by means of samples taken from exploratory bores. As a number of important utilisation characteristics are connected, not with the relatively homogeneous organic mass of the coal, but with minor components such as the ash content and particular constituents of the ash, it is necessary to know how bore samples relate to coal finally used in the process concerned. Tests are described in which the statistical parameters associated with bore sampling, operational sampling and sample reduction and laboratory procedures including a range of coal analytical methods were determined. These indicated properties where analytical errors were relatively high and where sample reduction procedures contributed substantially to imprecision in results. They also showed the effects of the non-homogeneity of brown coals with higher than normal ash contents. A further experiment explored the relationship between samples taken at various stages in the course of test boring, digging, and burning a defined 'block' of coal, and demonstrated an apparent increase in the proportions of adventitious mineral constituents as the 'intensity' of sampling Increased.

Jan 1, 1976

By Svenson D

Most exploratory drilling in the N.S.W. coal fields has been conducted using convent- ional diamond drill rigs of modern design, us- ually truck or trailer mounted. Conventional diamond drill rigs have also been used exten- sively by the Queensland Department of Mines for coal exploration. However almost all of the exploratory drilling of surface mine coal prospects throughout Queensland has been conducted using rotary rigs typified by the Mayhew 1000 truck mounted unit. The rotary rig has proved capable of both rapid non-core drilling and core drilling with high core recoveries when modern core barrels have been used by experienced drillers. For deep or continuous core drilling, wire-line equipment is now in general use. Both wire-line and conventional coring is effected using stationary split inner tube barrels, for minimum core disturbance, maximum core recovery, ease and accuracy of logging and sub-sectional sampling. Diamond core bits are generally required in N.S.W., with water circu- lation. In Queensland, the generally softer coal measures strata can be successfully cored using tungsten carbide bits and air circulation is the preferred method where possible.

Jan 1, 1977

Changes in prices and costs change the mineable grade and the profitabil- ity of an ore reserve. In a static world the grade required for an ore reserve is measured by the ratio: Cost/tonne of ore x 100 Price received/tonne of product and profitability by the ratio:- Price received/tonne of product Cost/tonne of product If the words cost and price refer to average cost and average price over some suitable period, say 3 to 5 years, the above ratios express the convent- ional wisdom of the mining engineer, and assume there will be no change in technology or politics.

Jan 1, 1979

By Coulter K. W

The commercial evaluation of coking coal from bore core data will begin with a technical evaluation of the coal properties affecting coke quality. Methods currently used for prediction of coke.properties from coal analysis are illustrated but in each case accuracy of measurement and prediction should be clearly understood. It is suggested that coal be initially valued from coking properties (base value) and adjusted for chemical properties (merit value). Final evaluation of coal can only take place as coke in the blast furnace where the coke is assessed under high temperature operating conditions. The commercial value of a particular coking coal will depend on many additional factors other than the technical properties.

Jan 1, 1977

Geochemical data on Australian granites and pegmatites9 and the.,mineral.components of these rocks, is presented and compared with that obtained in similar studies in.the U.S.òS.R and:.elsewhere.The petrochemical character of tin granites and the trace.-chemistry of their component minerals, particularly biotites, have some significance as ore guides in prospectingfor tin.The primary geochemical dispersion of tin can be readily tested both in the laboratory and field by colourimetric methods, after volatilization with ammonium iodide, using modifications of.the method described by Wood (1958).Secondary dispersions of tin in residual soils or.alluvia can likewise be readily tested by rapid colourimetric methods in the field, but simple hydraulic methods,.handling larger-. sample volumes, give reliable outlines of dispersion patterns.

Jan 1, 1963

The term "joint venture" lacks any precise legal definition but is typically used to denote a form of legal relationship which is neither a partnership nor a corporation. Nbst joint ventures are contractual relationships which provide for the sharing of mining leases and production facilities and for the sharing of costs, but which enable each joint venturer to carry on his own separate business. The rationale for such relationships is that each participant: retains independent taxation status may independently grant direct security over his interest in the project assets for financing purposes Bankers prefer to lend to incorporated joint ventures (i.e. corporations in which all of the joint venturers are shareholders) but will lend to individual joint venturers provided the joint venture agreement does not imperil their security; i.e. provided there is a "bankable" joint venture. The carpeting objectives of joint venturers and their bankers may be reconciled and unnecessary conflict avoided by the timely inclusion of appropriate provisions in the joint venture agreement before financing negotiations commence.

Jan 1, 1983

By N Patzelt, T C. Logan, I B. Klymowsky

In 2003, NEWMONT MINING CORPORATION, the worldÆs largest gold producer, set out to prove that High Pressure Grinding Roll (HPGR) technology is sufficiently robust and reliable to be considered for the treatment of hard rock gold ores. In collaboration with POLYSIUS, a significant trial was conducted and 127 600 tonnes processed, successfully proving the HPGR capabilities on the Lone Tree Mine, Nevada ore û one of the most competent and abrasive ores in the industry. The success has led a number of mining companies to consider HPGRs for the comminution of gold and copper ores.

Jan 1, 2004

Ranger Uranium Mines Pty. Ltd. operates an open pit mine and ore treatment plant in the Northern Territory designed to produce 3 000 tonne/yr of U308 in yellowcake from 3 500 tonne/day of mill feed. The construction of this project was completed in 1981, 12 years after the discovery of the orebody. Wright-Davy, a Joint Venture of Wright Engineers and Davy McKee Pacific, were the Project Managers and Designers of the $270 million ore treatment plant and associated infrastructure. The project was designed in Sydney in -an office integrated with the Client, staffed by 35 key personnel drawn from Wright Engineers and Davy McKee, supplemented by personnel hired for the project. The peak Wright-Davy workforce in Sydney of 200 contained 113 design staff. The design principle of using the best practicable proven technology resulted in a plant which easily produces its design output using ore types outside the design criteria. The structuring of the project systems and industrial relations policies contributed to construction being completed within time and under budget. The plant was built without any major industrial dispute occurring and no dispute arose due to the uranium issue.

Jan 1, 1983

This paper compares and evaluates the impact of income tax and value-added tax on the decision to explore for minerals or to develop a mine in four countries: Australia, Papua New Guinea, Argentina and Indonesia. Three aspects are considered in depth:- domestic tax rules applicable to mining projects;- taxation of foreign mining investment and foreign providers of expertise;- taxation of project finance (other than equity) from foreign sources.Specific tax issues discussed include tax deductibility of various costs, treatment of tax losses, special tax incentives, comparative treatment of various corporate structures, non-resident withholding taxes, and tax costs of various forms of project finance. The paper also illustrates the comparative impact of income tax on rates of return by means of a simulation of a mining project in each of the four countries. The simulation demonstrates why the highest rate of return may be obtained in Argentina and the lowest in Australia.Relevant features of the income tax systems in each country (at 15 February 1990) are summarized and compared in several tables annexed to the naner.

Jan 1, 1990

The Golden Cross mine is a Joint Venture between Coeur Gold New Zealand Limited, as Manager, and Viking Mining Limited The mine is targeting Zero Lost Time Accidents as a goal. The Golden Cross operation produces gold and silver from both underground and open pit. The mine is based on an epithermal gold-silver deposit. Treatment of ore is on a campaign basis for each ore type (ie underground or open pit). Milling is conventional SAG Mill and Ball Mill grinding circuit followed by carbon in pulp recovery of gold and silver. All tailing materials are treated through the Cyanisorb process to reduce cyanide levels prior to being discharged into the tailings dam.

Jan 1, 1995

The liquid products of low-temperature carbonisation of coal are of variable composition, very much influenced by the rank and type of coal, and process parameters. In general the tar contains a high proportion of phenols and a low proportion of bases. The neutral oil is more analogous to a thermally cracked petroleum oil than to a high temperature tar. Present practice and possible future trends in the production of chemicals and liquid fuels from low temperature tar are reviewed in the light of recent work on the detailed composition of the tar The phenols and aromatics will probably continue to be of most value, with the bases a useful source of spec- ialty products. However the high aliphatic content of the neutral oil (particularly 1-olefins and n-paraffins) is bound to receive more attention for chemicals as well as for liquid Fuels.

Jan 1, 1969

By R F. Johnston, I D. Sommerville

This paper presents an overview of the researches carried out in our laboratory on the application of plasma in recovery of alloy elements from waste slags and the treatment of lean ores, which are examples of advanced materials processing. After briefly reviewing the early work on the reduction of nickel, chromium, manganese, vanadium and titanium oxides, and a short investigation of the reduction of titanium oxide from the slag resulting from the blast furnace smelting of a titanomagnetite ore, the paper concentrates on the more recent studies on the reduction of an Australian scheelite. In some of these experiments, aluminium was used in addition to carbon as a reductant, in virtually all cases complete reduction was achieved within a relatively few minutes even with carbon alone during plasma processing. It therefore appears that this technique provides a possible processing route to facilitate the recovery of valuable alloying elements from non-traditional sources, or to permit process step elimination.

Jan 1, 2000

This paper describes an investigation of the sampling problems which contributed to erroneous Concentrator production forecasts at the mining operation of Bougainville Copper Ltd (BCL) in the North Solomons province of Papua/New Guinea.Reference figures provided by independently verified commercial shipment data demonstrated the existence of a bias in the calculated Concentrator production; the challenge was to identify systematic errors in each of the contributory measurements (feed tonnage and feed, tailings and concentrate grades).The uncertainty surrounding specific sampling and measurement errors precluded optimum metallurgical control and performance of the milling circuit, encouraged disputes about the difference between Mine versus Concentrator production estimates, and cast some doubt on efforts to follow political guidelines concerning a maximum feed tonnage or recovery oriented mill operating concept.An evaluation of routine results as well as specifically targeted test work identified the sampling errors associated with measured individual parameters.The emphasis in this report is on the procedure for quantitative error assessments.The measured performance of a mineral dressing plant is subject to a systematic error balance which can be derived from the more familiar weight and metal balances such as the two- or three-product formula.The resulting equations are generally valid, and they are applied to the measurements obtained at BCL's Concentrator to illustrate the method.

Jan 1, 1976

As a number of underground fires have unfortunately happened in the Broken Hill mining district, the writer trusts that a paper dealing with such a subject may prove of interest. To simplify matters, the subject is classed under three mainheadings- I Origin of fires; II Methods of subduing them; III Precautions to minimize the risk of their occurrence.Underground fires may be started in three ways - arson, spontaneous combustion, or carelessness.With regard to the first-mentioned cause, direct evidence is usually lacking to prove that any fire has been caused maliciously; Though definite proof of spontaneous combustion having been the cause of a mine fire has not been brought forward, nevertheless it should be considered, especially in the case of sulphide ore bodies of a more or less friable nature. The writer has been informed on reliable authority that in an open stope on the...

Jan 1, 1911

By L Crew, S Jackson

A trial of an Adept Online Ore Sizer (OOS) was undertaken at the WMC Leinster Nickel Operation (LNO) in the first half of 2000. During this time the On Line Ore Sizer has been shown to be a robust and accurate instrument for measuring mill feed ore size. Data collected during the trial indicates significant variation in the F80 of the SAG mill feed. The effects of feed size on milling parameters such as mill weight, mill power draw and mill efficiency appears to be dependent on the ore blend treated. With some ore blends a weak positive correlation was found between ore size and mill weight and milling efficiency but with others no correlation is evident. It is believed that the OOS will become a vital piece of equipment in the future as LNO continues to optimises its milling circuit.

Jan 1, 2000

By Watson D. F

Armstrong's (1983) criticisms of PhiIip and Watson's (1982b) note on optimal drilling patterns are based on misinterpretation, supported by errors in geometry. Furthermore, Armstrong argues conceptually from the perspective of Matheronian geostatistics, as does also Rudenno (1983a, b). Thus, both authors embrace a global, probabiIistic method of assessing spatial data sets, an approach that must be contrasted strongly with local, deterministic interpolation methods. Some of the important assumptions of geostatistics are outlined and the non-unique nature of the method discussed. A probabilistic approach can be judged appropriate when exploration data are erratic, or known to be unreliable, or when extrapolation is desired. Where data are treated as exact, kriging can give the most biased result if tested against other interpolation methods. We reiterate our previous conclusion that the equilateral triangular grid is approximately 30 per cent more efficient (in terms of numbers of drill holes) compared with a square grid for the same maximum interpolation distance. This is simply due to the improved isotropy of sampling. New, locally-based, deterministic methods for computing ore reserves seem to be required.

Jan 1, 1984

By D J. Clark, S Hewson, T Li

Cadia Hill Pit is a gold copper porphyry deposit hosted in monzonite. The pit slope design is primarily based on structural controls related to faults and shears with largely massive rock masses between the structures. The slope design attempts to achieve an optimum configuration at a bench to overall scale, considering economics and safety implications against the geotechnical and structural conditions. To date the slopes have been mined at interramp angles of up to 60¦ over heights of 120 m. Limited slope and batter failures that have occurred are structurally controlled and occur rapidly. The pit-mining schedule requires concurrent mining of part of the final pit walls and the progressive interim cutbacks. Engineering and operational solutions to hazard reduction and risk management issues have been implemented wherever viable to æengineerÆ out the hazard and mitigate the risks. However, comprehensive management plans and operating procedures have also played a vital role. This paper details the management plan and the operating procedures that have been developed and implemented to mitigate the risks associated with rock falls.

Jan 1, 2003

By Moore R

An intensive safety campaign at Mount Isa Mines Limited from 1956 to 1966 saw the lost time accident frequency rate fall to half its original level. A review of the safety programme was carried out in 1967 and in 1968 the Five Point Safety System was introduced. The seven years since its introduction have been years of significant achievement both in production and safety. Improving safety is a fundamental part of Mount Isa Mines Limited's policy and this system has been a major tool in implementing that policy. To be successful personnel need to be prepared and trained for its introduction and subsequently counselled on its use. A carefully prepared programme is required to phase in various aspects of the system and to make use of complementary steps. The system has been a success and it is anticipated that the continued drive to improve the use of principles of the system will further improve safety. It is hoped that this paper will be of value to those personnel concerned with industrial safety in Australia.

Jan 1, 1975

In engineering applications of explosives for rock breaking, the released energy is expended mainly into heat, rock crushing and fracturing, seismic waves, air blast, and noise. Those parts of energy which pass into seismic waves and air wave create environmental problems since they are transmitted away from the blast site. In order to predict the environmental effects accurately, one must be able to predict the energy distribution at the source. The energy distribution at the source is significantly controlled by the blast constriction. Consequently, the accuracy of prediction and control of ground vibrations generated by blasting is affected by various matrices of blasting constriction.

Jan 1, 1986