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By Minglin W, Zhixing L

The laws of detonation wave velocity variation in propagation process along the charge under channel influence are investigated widely in this paper. The result is obtained by blasting experiments. Bore hole is simulated by plastic tube or steel pipe (with outer diameter 45 nun, inner diameter 40 or 41 mm). Blasting experiment is carried out with a cylindrical charge of 32 mm diameter. The author analyses the characteristics of energy distribution along the charge under above-mentioned conditions. Reasonable initiating position and initiating direction are also analysed. A double-direction initiating method which consists of several initiating charges is put forward. The blasting effect of this initiating method when used in underground mining is stated out.

Jan 1, 1990

By S Blackburn, T Veasey

The physical and mechanical properties of rock can be measured by a variety of standard tests, and studies have shown that there should be a fundamental connection between breakage in comminution and rock æstrengthÆ. The current study aims to develop the ring-loaded strength test, used as an industry standard for the characterisation of brittle ceramics, for determination of comminution behaviour from exploration borehole core samples. The test procedure is simple, reproducible and can yield 250 separate measurements from a one metre length of drill core. The effects of material grain size and fabric on the degree of scatter of results have been investigated with respect to the ring-loaded strength test. This study has also compared the ring loaded strength to the chevron bend test used to determine the Mode I fracture toughness. A wide range of rock materials have been studied and with further work it is conceivable that an operational work index could be obtained directly from exploration drill cores tested via the ring-loaded disc test.

Jan 1, 2000

By J Player, K Braddon

High productivity mining is the key to the financial success and stability of modern mines. This can be achieved through the use of new technologies, the development of innovative work practices and optimisation of the mining method to suit the mining environment. Big Bell Mine is a 1.7 Mtpa longitudinal sublevel caving operation at a head grade of 3.14 g/t. Annual production is 170 000 ounces of gold. The selection and implementation of bulk emulsion explosives was seen as the logical progression from blow loaded ANFO for the high tonnage rate required from the longitudinal sublevel cave. Prior to the implementation of bulk emulsions an investigation was required to examine the technical and financial benefits available with the introduction of bulk emulsion. This paper examines the review process and the successful implementation of bulk emulsion explosives at Big Bell.

Jan 1, 1999

By Walsh V

The Australian economy has been adversely affected by the hesitation in developing countries to commit to the construction of .new coal-fired power stations. World coal trade which was expected to grow at an appreciable rate has stagnated, world export coal prices have plummetted, and facilities in place in Australia for the production and export of coal are being underutilized. While in some countries this hesitation has been caused by a reduction in electricity load growth, another cause has been the unduly long lead-time imposed on developing countries by the conventional "Banker's Approach" to the planning and initiation of commitments to finance and construct coal-fired power plants. In some countries electricity growth has been met by increased usage of indigenous energy resources, even though this involves costs in excess of imported coal-fired power generation. The avoidance of foreign exchange commitments in these cases can however be desirable. In many other developing countries however, fuel oil continues to be used for power generation at a cost in foreign exchange of up to 50% above the total cost of coal fuel plus capital to construct a new coal-fired power station. The conventional "Bankers Approach" to new power station planning imposes the need for successive feasibility studies to satisfy the normal processes of international development lending agencies. No feasibility study can however, show how keen vendor countries may be to win major power plant contracts; and no feasibility study can determine whether the power station eventually procured will be one of the more reliable, at better than 80% availability, or one of the more unreliable at worse than 60% Availability.

Jan 1, 1987

By Wright S, Jorgensen F. R A

The reaction between lead sulphate and a number of base metal sulphides (galena, sphal- erite, chalcopyrite and synthetic pyrrhotite was studied as a means of desulphurizing lead sulphate containing fumes and residues to levels acceptable as ISF feed. The reactants were mixed with 50% zinc oxide to act as a "basket" to contain the molten products of the reaction and pressed into small briquettes 20 mm in diam. Factors such as temperature, time and the composition of the atmosphere were investigated. Using the PbS/PbS04 system as an example it was shown that the reaction became rapid above 800¦C and that both sulphur dioxide and oxygen in the atmosphere were detrimental to achieving low sulphur in the product. In an inert atmosphere all the sulphides when roasted for 1 h at 1000¦C gave results corresponding to the elimination of more than 95% of the sulphur in the reactants. Leach plant residues were considered for use as the "basket" material. It was shown that the residual sulphide and sulphate components of the residues underwent similar reactions to those experienced by the pure systems.

Jan 1, 1987

By Qisu W

The ground vibration produced by the bench blasts of a single hole and a row of two or three holes is recorded in an iron mine. Using the seismic signal generated by a single-hole shot as the source function, we have developed a computer program of a simulating ground vibration by bench blast. The reasonable delay time of blast in the iron mine has been discussed tentatively with the Fourmap invented by Anderson, D.A. The seismograms measured from the single-row blasts of two or three holes have shown the method of simulating vibration is feasible on the whole. For large scale production blasts, a combination of the vibration simulation and the high-speed photograph is used to choose the delay Time.

Jan 1, 1990

By D La Rosa, W Valery, A Jankovic, S Ese

Metso Minerals Process Technology Asia-Pacific (MMPT-AP) has been working with many mining companies worldwide performing æMine to MillÆ or Process Integration and Optimisation (PIO) studies. MMPT-AP has developed a proven methodology to improve the efficiency of the mine-mill interface and gain maximum benefit. The PIO methodology involves rock characterisation, mathematical modelling and simulation to generate a list of operational and control changes for both the mine and concentrator. Following the methodology, the list of recommendations is developed relatively easily; the more challenging part depends on the company. Success of a PIO project relies on the ability of an organisation to implement change û both operationally and culturally: the human element. When a PIO project is started, there is initial interest and commitment from the company. But how can this be maintained? How does an operation know if the benefit continues? MMPT-AP is now developing long-term relationships with clients to ensure that the increased production and improved efficiency continues. Direct and indirect measurements are used to determine the key factors involved and to understand the cause/effect relationships. Simulation tools also can be used to compare current with recommended practices û so when material properties vary over time, the benefits can still be quantified. PIO is about empowerment: by measuring and understanding what parameters affect concentrator performance, the site personnel now have the knowledge to make a difference. Rather than simply reporting variable or poor concentrator performance, operations can predict when production will be affected and put controls in place to prevent it from happening. This requires support and commitment from the company or æbuy inÆ. Ensuring this buy in continues is the challenge facing every company involved in PIO work û but the benefits are well worth it. This paper will review MMPT-APÆs experiences in implementing PIO projects in the long term: from both the consulting and operational viewpoints. MMPT-APÆs involvement with a number of companies will be discussed as examples of what works and what does not.

Jan 1, 2007

By Gray N. B, Floyd J. M

To gain further understanding of the operating efficiency of the BHP Slab and Plate Products Division (SPPD) RH vacuum degasser, physical and mathematical model studies of the process have been undertaken. The purpose was to investigate how the various process parameters affect the liquid circulation rate, to visualise the flow patterns, and to identify and eliminate the cause of localised wear in the downleg. In the physical model mixing times were measured using an acid tracer technique. The results were applied to predicting trends in times required to obtain homogenous melt composition under varying conditions. A 2-dimensional mathematical model describing the liquid metal flow has been developed using the PHOENICS fluid-flow package. The physical model results were simulated and incorporated into the mathematical treatment and an improved design for vessel geometry is proposed. The effect of rounding the downleg entrance or installing a baffle between the legs is discussed.

Jan 1, 1987

By Fisher WJ

The'treatment of the South Alligator valley uranium ores passed through three phases dictated by economic circumstances during the years 1956- 640 In the first phase high grade ores were treated by hand sorting and wet gravity separation for recovery of high grade concentrate to meet a United States Atomic Energy Commission (U.S.A.E.C.) contract for plus 50 per cent pitchblende concentrates. Secondly tailings from the gravity plant and some high grade ores were trucked to Rum Jungle and sold to the Australian Atomic Energy Comm- ission (A.A.E.C.). Thirdly solvent extraction plants were built at Moline (previously Northern Hercules) by United Uranium N.L. (UOU.N.L.) and at the South Alligator River by South Alligator Uranium N.L. (SOA.U.N.L.). These were the first solvent extraction plants designed in Australia, as earlier plants used the ion exchange process for recovery of uranium oxide. The plants were small, indeed the S.A.U.N.L. 15 ton per day plant was possibly the smallest commercial plant known, but they operated efficiently with good recoveries, and were placed on a care and maintenance'òbasis when contracts were filled. Sulphuric acid was supplied in bulk to both plants by the A.A.E.C. from the 30 ton a day acid plant at Rum Jungle. Gold was recovered as a by product of uranium ore from the Moline plant.

Jan 1, 1968

By Kuruppu M

Geotechnical design plays a key role in mine design. A proper geotechnical design provides a safe working environment and facilitates efficient mining operation. There are mainly three design approaches: (i) judgmental, based on observational and experiential facts, (ii) empirical, based on empirical design formulae; and (iii) analytical, incorporating numerical analysis. Most design applications are based on the design methods one and two as mentioned earlier. However, complexities arise in deep underground mining operations and deep open pit mines. These complexities and difficult geological environment introduce more uncertainties and simple empirical formulae would not be adequate as a design tool. These situations require numerical modelling and analysis of the design problems including interpretation of the results obtained from the analysis. There are several tools available for performing the numerical modelling and analysis. A brief review of the available tools is provided. The authors selected ANSYS (a general purpose finite element analysis tool) for use in mining geomechanics and geotechnical design. This paper includes several examples demonstrating the applicability of this software in designing mining structures. The authors hope that the design examples will demonstrate the use of the numerical modelling and analysis applications in excavation design.

Jan 1, 1995

By Northcote GG

There are many underground mines with shaft or decline access with limited production capacity or where the mine may become uneconomical as trucking costs escalate with increasing depth of the decline. In such cases a need may exist for a shaft hoisting system which can be constructed more quickly and more economically than a shaft sunk by conventional methods. Relatively cheap small diameter shafts can be constructed by raise boring. This paper describes a simple hoisting system which has been designed to take advantage of the benefits of raise boring. The system uses twin bored raises with a double drum winder hoisting a skip in each hole. The design concept is based on 1. accepting that the raises cannot be truly straight or vertical, 2. using the raise to guide the conveyance, and 3. minimising operating, maintenance, and capital costs. The hoisting system requires a certain degree of accuracy in the alignment of the twin raises. A survey of raise boring practice showed that the required accuracy could probably be achieved with conventional techniques. However it was thought it would be necessary to survey the pilot hole during drilling and to be able to correct the hole if deviation became

Jan 1, 1978

By K L. Silversides

Shales form distinctive peaks in natural gamma downhole logs, which are used to manually identify the location of ore boundaries. These shales form important lithology markers that can potentially be automatically identified using Gaussian processes. This approach is trialled using data from a typical iron ore mine in Western Australia which contains the Marra Mamba sequence of the Hamersley province.The method uses Gaussian processes (GPs) with a single length scale squared exponential covariance function. A library of 8 m sections, where natural gamma measurements were taken at 10 cm intervals down the hole, was used to train the GP model. This library was iteratively improved and was tested using natural gamma logs that were not included in the library. Areas that were misclassified or were not clearly classifi ed were added to the library. The new library was then used to train the model and improve the results. The trials used a double gamma peak from the NS3 and NS4 shales at the boundary between the Newman 1 and Newman 2 ore zonesin the Newman member and the AS1 and AS2 shales at the base of the West Angelas member. The results show that both boundaries can be identifi ed with an accuracy of over 99 per cent. The classification has the highest accuracy on undeformed shales. This method provides a fast, accurate and objective identifi cation of shale and ore boundaries and can potentially replace the current manual detection.

Jul 11, 2011

Despite mineral sand occurrences having been noted since the 1970s, the Wemen North Mine is the first operation to commence commercial mining within the inland Murray Basin. The deposit was discovered in the 1990s and, following lengthy resource development, mining commenced in 2001. This initial mine was established as a pilot operation to test the commercial viability of mining in the Murray Basin, with subsequent expansions planned if the mine proves successful. The deposit lies beneath arable farmland close to the Murray River and is hosted by Pliocene marine sands, with a geometry resembling a classical beach strand placer. The operation utilises traditional dry mining overburden removal techniques, with ore mining carried out using a floating dredge and concentrator. This paper looks at the geology of the Wemen North deposit, the mining techniques and challenges as well as grade control practices employed to mine this palaeo-beach placer deposit.

Jan 1, 2003

One of the most frequently asked questions at the feasibility study stage of a project is, æhow big can one go?Æ This important question effects costing and efficiency of metallurgical equipment, the real estate required and the operating plant strategy.The presentation covers both engineering and process considerations and explains the limits that exist today and explores future trends.The paper is specific about large slurry application usually found in gold applications; however, it could apply to silver and uranium or other dense media leach duties.Agitator drive sizes are examined as well as process risks associated with large tank agitation. New technology has increased the maximum tank size and designers are now experienced in tank volumes in excess of 5000 m3. Tanks of 6000 m3 have been agitated and 10 000 m3 tanks are within present engineering know-how and scale-up.Fabrication techniques for shaft and impeller designs exceed the existing standards and new specifications will be needed to cover large mixer design. The paper covers certain aspects of mechanical design and proposes alternative standards that are more appropriate. Process considerations such as fluid natural frequency as well as typical superficial velocities for efficient operations are examined. Scale-up techniques based on existing and new technology are also examined to ensure a successful installation.The presentation therefore covers the majority of large mixer design questions that are frequently asked.

Jan 1, 2006

By Peck RC

The ore body at Elura contains fine grained galena and sphalerite in a matrix which is mostly pyrite. A differential flotation circuit concentrates lead and silver in the first section and zinc in the second. The lead section, shown in figure 1, was sampled in detail previously and the metallurgical performance assessed on a size by size basis. That assessment took no account of liberation and given the fine grained nature of the ore body, this could lead to an incomplete picture of the flotation performance. Liberation measurements were made using the QEM*SEM system on four size fractions of samples taken from seven different streams in the lead section. Using the mineral flows obtained from the mass balance around the lead section an excellent liberation balance was obtained which enabled the effect of liberation on the flotation performance to be assessed. The measurements indicated that only 17 per cent of the galena and 28 per cent of the sphalerite in the flotation feed was liberated. On the other hand 31 per cent of the gangue iron sulphides were liberated. The final concentrate was largely composed of locked galena and locked iron sulphides with 85 per cent of the product being locked. There was a small but significant fraction of liberated pyrite.

Jan 1, 1991

Valuers will often intuitively express the probability that property value will exceed a certain amount . . . 'I think the chances that the value will exceed $50 million are excellent. The chances that they will exceed $80 million are poor'. This paper shows how it is possible to combine the uncertainties of the value of several key items to provide an estimate of the probability of a certain overall value being achieved. The valuation of a large copper/gold deposit was naturally influenced by uncertainties in the base assumptions of costs and metal prices. Potential acquisition of the property through share purchase raised the issue of what was a reasonable intrinsic value for the shares. Market considerations could be used to appropriately adjust the intrinsic value. After a range of possible metal prices and operating costs were determined, estimates were made of their probable distributions. By combining these probabilities in a random selection, a range of property values was calculated. Each value had its respective probability of occurrence. This allowed a most likely value of shares to be calculated. This paper demonstrates how the valuer's intuition is complemented by numerical analysis.

Jan 1, 1994

By Lovett EP, Johnson CR, Dunlop GA

Seven streams of a low tonnage pilot plant operation on Cu/Pb/Zn ore from the Golden Grove Project were continuously assayed using an AMDEL In-Stream Analysis (ISA) system. The ISA instrumentation is briefly described as is the calibration procedure employed. The successful application of this instrumentation in the dynamic environment of a pilot plant operation is discussed. The operational sequence of the Golden Grove pilot plant is outlined along with the original project objectives and how they were achieved by the implementation of ISA. Results for the different complex flowsheets used are discussed, followed by the perceived benefits of installing such equipment in this operation.

Jan 1, 1986

Evaluation of reserves on a production scale within a shear-hosted gold deposit is complicated by the nature of the mineralisation itself. The 'payable' ground seems to be confined to areas with intense shearing, while the remainder of the deposit is characterised by 'background' mineralisation at a very low level.

Jan 1, 1993

Projections of metal requirements for Japan and the United States indicate growing competit- ion for Australia's mineral output and a critical need for continuing discovery of new reserves. These projections may be modified by economic, social and political controls - the most import- ant factor probably being a shortage and the high cost of risk and development capital. Changing ownership patterns toward joint ventures and increased state participation are anticipated. New developments in global tectonics and metallogeny delineate favourable zones for ex- ploration and permit establishment of priority search areas even in regions of poorly known geology. Declining ore grades and special character- istics to meet technological requirements may modify identification and evaluation criteria. A broad approach considering all environments of concentration within the geochemical cycle is re- quired within any metallogenic province. The exploration geologist must be able to integrate geological theory, mining technology and financial analysis to establish well defined exploration objectives, in terms of economic and geologic models, in concept-oriented programmes.

Jan 1, 1973

By G Kuntz, V Wall, B New

The prime aim of the Campbell Mine project was to develop a 3D geological model for the Campbell-Red Lake system to contribute to an exploration model for the region. The base data is composed of over 60 years of geological data covering an area of 16 by 8 km, and from surface down to 1830 m depth. This paper concentrates on the methods used in the GeoSpace system for the processing, integration, display and interpretation of such a large and diverse data set. A block model was developed that recorded the relative frequency of each geological feature within each block. The data input for the block models were based on recoding of the Campbell Mine drilling and channel sample databases into lithological, alteration and structural subsets. The value for each geological characteristic inserted into each block is calculated from all available data that falls within the block. Relative and absolute comparisons of the individual variables provide a targeted outcome from which the blocks are coloured for visual inspection. Different combinations of variable comparisons can be evaluated so that required features are highlighted for interpretation. Blocks are displayed to illuminate the ædominantÆ rock type, according to a formula that may be varied interactively to display the features required by the geologist. This flexibility allows rapid remodelling of lithological distributions, commonly highlighting minor lithological packages not readily visualised in, and interpreted from, drillhole traces alone. The 3D geological model was built from the drillhole datasets and old mine plans utilising standard 3D mining, GIS and database software, with several iterations of plan and sectional interpretation. Near surface bedrock geological interpretations were further constrained by low level aeromagnetic data. The Geospace approach employs an innovative technique for visualisation of the distribution of lithological packages and alteration via block modelling. The method utilises the block model format of data handling as it is considered to be more visible than drilling, flexible enough to incorporate a wide range of data sources, and allows for spatial proximity relationships to be investigated. The method is a simple form of processing large data sets so that results are clearly visible. The calculation is much more rapid than estimation procedures, and does not have any requirement for geostatistical interpretation which is also time consuming. Geospace is not unique to any mine environment software and it is expected to be able to be performed in any system. The proper portrayal of the internal structure of the mineralised body will provide practical input to exploration and mining principally in the areas of resource estimation, exploration vectoring and ore/waste characterisation and may be incorporated with other data to include mine support and mine scheduling.

Jan 1, 2003