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The Antarctic Peninsula consists of accretion complex sedimentary and volcanic rocks, talc-alkaline magmatic are rocks, marginal basin sediments and extension-related alkali basalts, dominantly of Mesozoic to Cenozoic age. Metallic minerals have been recorded at "250 localities but two thirds of these are innocuous occurrences of Fe+Cu accessory minerals. The remaining -70 localities are related to hydrothermal mineralization processes. Metallogenetic associations identified are: vein and breccia-hosted Fe+Cu+Zn+Pb+Mo or Fe+Cu+Mo+Mn, shear-hosted Fe+Cu, volcanogenic Fe+Cu and pegmatite-hosted Fe+Cu+Mo+Mn. Anomalous Au, Ag, As, W and Sb also occur but are not of economic interest. Metallogenic zoning is unproven and genetic models are uncertain, possibly involving volcanogenic, epithermal to hypothermal vein and porphyry-type systems. Substantial field and laboratory studies are required to understand distribution and Genesis.

Jan 1, 1987

This paper outlines some of the recent developments in Spiral Concentrator design, with particular reference to the range of Reichert spirals supplied by Mineral Deposits Limited, typical applications, and test or operating data, are also provided for the different series of spirals now available.

Jan 1, 1978

The patterns of flow of reaction gases through the flash furnace at the Kalgoorlie Nickel Smelter were simulated in a 1:20 scale model using a flow of water. Particular features of the flow down the reaction shaft, through the settling chamber and into the uptake leading to the waste-heat boiler were examined. Inferences were made concerning the effects of the patterns of flow on the efficiency of the smelting reaction, on the entrainment of dust by the gas stream and on the erosion of the refractory lining of the furnace. In addition, the effects of geometrical modifications to the arrangement of the concentrate burners and to the profile of the settling chamber were explored by making these changes to the model and observing the resulting variations in the patterns of flow.

Jan 1, 1991

By Armstrong M

The highest grades of the Porgera gold deposit, Papua New Guinea, are contained in Zone 7 due to the presence of the Roamane fault, which acted as channelway of the gold-bearing fluids. Prior to the development and underground mining of this fault-controlled high-grade zone it was critical to provide grade estimates of relatively small mining units, and of the proportion of mining units above cutoff. To be applicable to Zone 7 of Porgera a grade estimation method should account for the following:1. the highly skewed and apparently lognormal distribution of the grades,2. the rapid drop off of the local mean grade and the variance as the distance to the Roamane fault increases,3. the presence of high grade pockets in the footwall, away from that fault, and4. the existence of variograms for the logs with sills parallel to the fault and without sills perpendicular to it.

Jan 1, 1990

By McKenzie C, Michaux S

Modern quarrying operations focus attention on blasting operations as a critical component in the overall cost-effectiveness of quarrying. Generally, optimisation of blasting has been linked to the processes of drilling, explosive consumption, secondary breakage, and product haulage to the primary crusher. This approach gives no consideration to the impact of primary crusher feed size distribution on downstream processes, or on the quality (ie shape and strength) of the final product. Blasting operations can be manipulated to produce a wide range of muckpile size distribution. This paper presents the results of studies into the impact of muckpile fragmentation on downstream crushing and screening operations, and includes measurements of primary blast oversize and muckpile fragmentation, together with measurements of size distribution, circulating loads and flakiness for various process streams throughout a quarry processing plant. This paper is an extension of other studies investigating the prediction and control of fragmentation from blasting, and the role of explosive performance in controlling muckpile fragmentation.

Jan 1, 1995

The economically significant seams in the Bowen Basin fall into four age groups, two in the Lower Permian and two in the Upper Permian. Coal deposition in the Galilee Basin did not commence until late in the Lower Per- mi-an and persisted into the Upper Permian. The Lower Permian and early Upper Permian coalfields of the Reids Dome Beds, the Collinsville Coal Measures and the Fair Hill-German Creek Formation are restricted to the west flank of the Bowen Basin. The uppermost Permian Rangal-Elphinstone-Baralaba Coal Measures have widespread distribution across the northern half and on both flanks of the Basin. Coal Measures in the subsidiary basins at BlairAtho/ and Ca/en were probably deposited at the same time as the Collinsville Coal Measures. The structure of the north west flank of the Bowen and the east flank of the Galilee Basin is essentially simple, but in the remainder of the basin doming and faulting complicate the structure. Also, bordering a large sec- tion of the east flank, is the Dawson Tectonic Zone, where the beds are tightly folded and faulting is intense. Cok- ing of seams is common in the northern sector of the Basin associated with igneous intrusion. With the exception of the Duaringa Basin on the east flank of the Bowen Basin, Tertiary sediments and basalt flows are more common at the western basin margin. Thick deposits of Tertiary sediments also occur in the south of the Galilee Basin. Con- sequently, coal subcrop, especially in the older, more westerly situated, coal measures is often at depths in excess of 100 m. East of this, the depth of weathering can be as shallow as 13 m and most of the coal subcrop is acces- sible to mining by open cut techniques. Coals deposited in the early Upper Permian are commonly more vitrain rich than those above and below. In the Bowen Basin, coal rank decreases from the north west to the south east, that is, from the semi-anthracites associated with the Dawson Tectonic Zone to the sub-bituminous coals of the southern Galilee Basin.

Jan 1, 1975

This paper describes the application of the Total Productive Management (TPM) technique as a performance improvement initiative for a coal mining operation. It discusses the objectives of TPM, with the driver for improved production performance being the Overall Equipment Effectiveness (OEE) of the equipment or process, and with the development of "ownership" as the behavioral approach to equipment management and continuous improvement through cross-functional and area-based teams. It illustrates the concept of equipment management as defects management.The scope for application of TPM to the coal mining industry is immense. The harshness of the operating environment can be a major generator of equipment defects, and a current paradigm in the industry accepts these defects as an unavoidable outcome defining maintenance costs in this environment. However recent benchmarking studies have highlighted that maintenance costs per operating hour in some mining operations are more than double the vendor's estimate of "best practice". The paper refers to these studies which also compare maintenance costs of fixed and mobile plant and equipment to "best practice" outcomes in comparable process industries.

Jan 1, 1998

Solution transport of gold and silver has occurred as a result of the chemical weathering of many Western Australian epigenetic gold deposits. Evidence for the remobilization of gold exists in the form of small crystalline octahedra, mustard gold, flake gold, and coatings on iron-oxide. This "secondary" gold is of high purity (low silver content). It is believed that the high chloride content of laterite profiles combined with the acid produced by the oxidation and hydrolysis (ferrolysis) of iron has caused dissolution of Au/Ag and Au/Te alloys. Gold, and less frequently silver, is subsequently reprecipitated in the profile nearby.Pyrite, which is a ubiquitous accessory of gold in vein or lode systems, is probably an important source of iron for the development of acidity. Where carbonate is abundant in the primary assemblage, neutralization directs the oxidation of sulphide to a path which produces thiosulphate, and an alternative type of Au/Ag oxidation process. Sulphide/carbonate ratios in the vein system, and adjacent wallrock are seen as important in determining the course and extent of remobilization in the oxidized zone of gold deposits.

Jan 1, 1984

By Greaves M. C, Amos M. D

A study was made of the instrumentation and technique of atomic absorption spectroscopy developed by Walsh of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia.The method was evaluated for the determination of silver in lead sulphide concentrate. The precision of the procedure developed is equal to that of the uncorrected fire assay method and the accuracy is greater.Brief mention is made of the use of this technique for the determination of silver and other elements in ores and concentrator products.

Jan 1, 1994

By Crapp C. E

The Collinsville Coal Measures consist mainly of arenaceous sediments but indude eleven named coal seams. The Formation outcrops around the northern end of tbe Bowen Basin where it attains a thickness of 700 ft. in the Collinsville-Scottville area and overlies Lower Bowen Volcanies with angular unconformity. Most of the members in the Formation thicken basinwards. The regional dip is about 8 degrees. The Formation thins southwards and does not occur south of the Bowen River on the eastern flank. On the western flank it is represented by 60 ft. of barren sandstone at the limit of our mapping, 12 miles south of the Bowen River. Two seams are mined, the Bowen and the Blake; coal from the former produces high grade metallurgical coke, and the latter seam is mined for steaming coal. Where mined, the seams are about 20 ft. thick. The coals are of medium volatile bituminous rank and the lower coals are of higher rank than those above them.Reverse faults striking across the Coal Measures have been delineated and the existence of areas of intrusive rocks has been established. Intrusions rose up fault planes and, as felspar porphyry sills, selectively intruded coal seams, decimating reserves of coalavailable for mining. One sill, in the Blake Seam, attains a known thickness of 115 ft. Because the distribution and thickness of the sills is rarely predictable, density of drilling has been greater than in most coalfields.INTRODUCTIONThe assemblage of sediments occupying the northern portion of the Bowen Basin (Fig. 1) may be divided into four formations of Permian age:The Upper Coal Measures (U. Bowen)The Middle Bowen Marine Beds (M. Bowen)The Collinsville Coal Measures (M. Bowen)The Lower Bowen Volcanics (L. Bowen).Of these, the Upper Coal Measures and the Collinsville Coal Measures are known to contain coal seams of workable thickness.

Jan 1, 1960

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

Sep 26, 2011

A case study of a landslide, which threatened vital infrastructure essential for the continuous operation of the Ok Tedi copper mine is presented. The paper presents a detailed description of the land- slide, outlines the assets at risk, and how the issue was addressed. This included the consideration of remedial options and the im- plementation of the most economically sound and geotechnically feasible remedial design which was completed within budget and on schedule. The paper is intended to highlight the responsibility of a mine based Geotechnical Engineering section in providing essential geotechnical investigations, design and professional advice on addressing stability issues in the infrastructure region.

Jan 1, 1997

By M Ridd

The Pasminco Century Mine (PCML) is located 250 kilometres north-north-west of Mt Isa in Queensland. As one of the worldÆs largest zinc mines, PCML comprises mining and milling operations at Lawn Hill, concentrate filtering and shipping facilities at Karumba in the Gulf of Carpentaria, and a 304 km slurry pipeline connecting the two operations.Mineralisation at Century occurs in the upper part of the Lawn Hill formation and is comprised of siltstones, shale and sandstone. Pyrite occurs immediately above the mineralised sequence, and throughout the footwall carbonaceous shale forming the lower proportion of the deposit. Zinc predominantly occurs as sphalerite (ZnS) and lead as galena (PbS). These sulfides are very fine-grained and may oxidise rapidly upon exposure. The pyrite, sphalerite and galena are the main potential sources of acid rock drainage (ARD) or heavy metal leachate at the mine site.To minimise the generation of ARD in the waste rock dumps, they are constructed in a specific manner and waste rock is classified into the following three classes based on competence and acid forming/consuming capabilities:Class 1: Competent rock, non-acid forming or acid-consuming material. Class 2: Non-competent, non-acid forming or acid-consuming material. Class 3: Acid-forming material. The generalised Waste Rock Dump Design for current operations comprises an outer zone of Class 1 material and inner zone with Class 2 and 3 material. Limestone is the Class 1 material used for both its structural support and acid neutralising capacity. Reserves of limestone at the mine site are limited. Net acid generation (NAG) tests confirm that a mix of limestone and shales can be net acid consuming.Field based and laboratory based trials have been established at PCML to quantify blending levels of limestone and shale that will produce leachates both neutral in pH and low in metal/salt concentrations. This paper will discuss the first six months results (of a two-year sampling program) from the trials.

Jan 1, 2004

By Das A. K

Investigations were carried out to understand the effect of liquid viscosity (u = 1 x 10-3 - 5 x 10-' Ns/m2) on the size of primary bubbles formed at high gas injection rates (Q = 100 - 1000 cc/s, U = 0.04 - 0.42 mach) under room temperature conditions using flush tuyere (3 mm diameter) operating vertically upward. Tuyere pressure fluctuations were correlated to the mode of bubble formation by simultaneously filming the bubble and the corresponding tuyere pressure fluctuations displayed on an oscilloscope screen. A simple mathematical treatment is presented to estimate bubble size in viscous liquids. The theoretical results are compared with the experimental measurements.

Jan 1, 1987

The kinetics of desorption of nitrogen from molten iron were investigated using the electromagnetic levitation technique. The respective influences of gas flow rate and surface active element (S) were examined. A second order behaviour with respect to the nitrogen concentration in the melt prevailed at all experimental conditions. Sulphur had a marked inhibiting effect on the desorption rate. The experimental results on the rates of nitrogen desorption have been interpreted with the aid of a reaction mechanism consisting of a sequence of elementary steps.

Jan 1, 1991

By Olofsson O, Durance M-V, Villeneuve J

Modelling of the Sala Agitated Mill (SAM) using a simplified solution to the population balance approach has been carried out. The rate of breakage is modified by the mill power, providing predictions of the resulting product size distribution for different grinding conditions and mill sizes. The power of the mill is estimated by a physically derived function, using an assumption that the mill power consumption mainly arises from the ball to ball friction within the mill. The grinding efficiency, depending on the media ball size and pulp density is approximated in the model. Experimental work on grinding a complex sulphide ore using a pilot scale SAM 7.5 has been carried out. Good agreement has been found between the data from the test campaign and the simulated values. The model has also been validated with experimental data from a pilot grinding of calcium carbonate and from an industrial mill. The model is included in the USIM PAC simulation software.

Jan 1, 1995

By Howell M. W

The purpose of this paper is to outline the main points in the construction of the various types of wire ropes more commonly used for winding in Australia; and the maintenance of the ropes, and cage and skip safety gear as practised at the South mine, Broken Hill.It should be mentioned that both of the shafts at present in use are dry, and both downcast with or without the assistance of the two exhaust fans normally in use: Night shift and week.-end overtime are practicaly non-existent.Thus, during night shift, the cages in No. 7 shaft are landed on the chairs at the surface, providing efficient covers for the· shaft, and allowing the maximum amount of rope to be wound on to the drums. This also applies to the cages of both No. 7 and No. 4 shafts during the week-ends.These factors, combined with electric winding and skip haulage, are calculated to obtain the best use of the ropes when properly attended.WINDING ROPES-TYPE AND CONSTRUCTIONThese ropes may be divided into four main types which will include the more commonly used constructions(a) One-size strand.(b) Warrington strand.(c) Flattened strand.(d) Locked coil.1. One-size strand as the name implies, is a rope the strands of which are constructed 9f wire of the one size.Usually the strands are of 7, 19 or 37 wires.

Jan 1, 1940

A synthetic gold-silver telluride material (mainly sylvanite) has been prepared and its physical and chemical properties checked. Flotation tests using a Hallimond tube were conducted using commercial xanthate collectors. At collector concentrations of 10-3M with the addition of 5 × 10-4 M CUS04, no obvious differences in the mineral recoveries were seen irrespective of whether amyl, secbutyl, isobutyl or isopropyl xanthates were used. However, when the concentration of xanthate was reduced to 10-4 M or in the absence of the copper sulphate activator, the effectiveness of the collectors was in the order: amyl > secbutyl > isobutyl > isopropyl > ethyl. Changes in the slurry pH appeared to have little effect on the recovery of the telluride mineral.Leaching tests of the precious metal telluride showed that both gold and silver dissolve in alkaline oxygenated cyanide solutions but at a much lower dissolution rate than metallic gold or silver. Both leaching tests and electrochemical measurements indicate that the dissolution rate of gold-silver telluride is controlled by the pH and cyanide concentration of the leachant.Roasting the gold-silver telluride materials in air at temperatures between 550 and 750°C resulted in its decomposition into a metallic gold-silver alloy and tellurium dioxide.

Jan 1, 1994

The accuracy with which block estimates are perceived is obtained by calculation of the kriging variance. This is dependent upon the model chosen for the semi-variogram of the deposit. For an extensive series of spherical semi-variograms the changes in the kriging variance resulting from various degrees of misassignment of the relative nugget effect are investigated. The results are reported as contour maps of percentage change in kriging variance as a function of the range and relative nugget effect of the true model.

Jan 1, 1985

By Shklyar FR, Bokovikov BA, Gordon YM, Scherbatskii VB, Yaroshenko YG, Shvydkii VS

The paper presents, for the first time, a complete mathematical model of the flow of gases in packed beds which describes the processes of gas-mechanics in iron blast furnaces and other shaft type smelting units. Good correlation between calculated and experimental results was obtained confirming the adequacy of the model. It is shown that the uniformity of gas distribution is related to the tuyere size and the extent of its protrusion into the furnace and that these variables may be used to regulate gas distribution across the furnace diameter. It is also concluded that furnace height has no significant influence on gas distribution. The necessity for a mathematical description of raceway phenomena has been experimentally proved. Conclusions from theory are shown to have profound implication to furnace design and operation.

Jan 1, 1975