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By Hatcher MI

Exploration undertaken at Copley diapir has located several occurrences of oxidized supergene and primary sulphide copper mineralization at the margin of the diapir or in adjacent country rocks. The mineraliza- tion is related to carbonate-rich epigenetic solutions which moved along major structural features closely associated with the intru sive diapir.

Jan 1, 1975

By Snowdowne J. B H

Rand Mines, Limited, located in Johannesburg, Republic of South Africa has recently completed feasibility studies which have lead to the initiation of two major coal strip mining ventures. A minicomputer based mine planning system was developed to perform the feasibility studies. The broad approach of this system is to utilise inter.-actively the specialist skills and interpretative abilities of mining engineers and geologists. This paper reports briefly on the outline of the system and at greater length upon certain aspects of its use.

Jan 1, 1977

Stability on surface mining projects is primarily controlled by five factors. These include structural geology, the most important of the factors, the existence of weak layers, primarily clayey gouge or clay infill, groundwater, blasting and weathering. Case examples of stability on many surface mines including some coal mines are presented. The experience and lessons learned are applicable in some way to stability of surface coal Mines.

Jan 1, 1986

The Agnew Mine No. 1 Ventilation Shaft is the largest diameter shaft blind drilled in a hard rock mining environment. The selection of this method of shaft development was based on achieving an accelerated mine development and exploration programme. Drilling the shaft from a pre-sink depth of 73m commenced on March 22, 1982 and the shaft was stopped due to rig structural problems at a depth of 750m, 280m from the designed depth, on February 12, 1983, 137 days behind schedule. While problems with rig mechanical availability, cutter life and lost drilling tools in the hole hindered progress and escalated costs, penetration rates above prediction were achieved and both the speed and safety aspects of the method were well demonstrated.

Jan 1, 1983

By Ibaragi K

High grade ores were intersected in 1981 by a scout drill carried out by the Metal Mining Agency of Japan during a reconnaissance dril ling programme. The original aim of the hole was to explore a deep target where geophysical anczralies overlapped the abandoned old drifts (gravity- high, resistivity-low by airborne EM, and resistivity-low near the surface and high at depth by Schlumberger deep sounding). Subsequently, a follow-up drilling programm was commenced by the Sumitcrro Metal Mining Co Ltd, and all the 18 holes intersected high grade ores. The resources were then "guestimated" to contain ca.120 tonnes gold with an average grade of 80g/t Au between -40m and +120n a.s.l. The underground development was started in December 1982 and the first crosscut intersected the ore body at 100m level (a.s.l.) in July 1985.

Jan 1, 1987

By Jensen W. S

The Mount Morgan ore-body is intersected by dykes to such an extent that it presents peculiarly difficult problems in extracting ore. These are shown on Plates Nos. LXVII. and LXVIII. Besides ,these dykes there are innumerable "heads," which alsoare a source of danger. Falls of ore occurred in the end of the year 1908, resulting in serious loss of life to miners employed. It was decided, after an exhaustive inquiry, to change the entire system of mining from the" flat backed stope system" to the" square set sectional system ," the latter being more flexible and allowing bad ground to be cut out from a safe position; but it became evident that, whatever system was adopted, there would be more or less danger unless all the dykesand heads known were picked up, and their continuation plotted on a special set of plans on which the general scheme of stoping could be plotted from time to time as work progressed. It is worth while pointing out that, in every other branch of engineering, it is usual to design the work, and that only in mining engineering has it been common to do the work first and plot it down afterwards.The term "sectional analysis" is familiar in most branches of engineering design, and as applied in this paper to mining, may not bear the same meaning, but the general purpose is analagous, and there is no other term used.

Jan 1, 1911

By Gordon A. R

The effect of various types of solid carbonaceOlls reductants on the rate of fuming of zinc from lead blast furnace slag was investigated at I250°C.The results of the laboratory experiments indicated that the rate of removal of zinc from slag depended primarily on the volatile matter contents of the reduclants. The effects of fixed carbon, moisture and ash contents were less significant.

Jan 1, 1992

By Murphy MW, Klaric SD

The history, operation and design of the Secor continuous rod production process is described. The effective operation of the plant is influenced by accurate monitoring and control of molten metal properties, mould release application, coolant application and composition and correct setting of all operating parameters. The continuity of operations, which is an essential feature of this type of plant, is also greatly influenced by the service life of wear parts in the operation. This paper deals with three principal wear parts which come into direct contact with copper during operation, these are:

Jan 1, 1985

By Lynch P

Oaky Creek Coal Pty Ltd. currently mines high quality coking coal from both underground and open cut operations at its Oaky Creek Mine. Coal is transported by rail to the Dalrymple Bay Coal Terminal south of Mackay and to the Gladstone Coal Terminal. Oaky No.1 Underground Mine, Open Cut and Highwall Mine have concentrated on seams from the German Creek Formation, one of the major productive coal measure formations in the Bowen Basin Coalfields. (Fig. 1) location map.

Jan 1, 1998

By Wright S

The feed to the Cockle Creek Imperial Smelting Furnace consists of mixed Pb/Zn con- centrates and lead sulphate-containing elec- trolytic zinc plant residues. Roasting was investigated as a means of desulphurizing the feed to less than 1%. Laboratory studies showed that two process streams were required in which concentrates containing 20% Pb were roasted separately from the leach residues. The residues along with fume from the roast- ing and a portion of concentrate were desul- phurized by means of the roast reduction reaction. Conditions were defined to give

Jan 1, 1986

Pisolitic iron ores (also known as channel iron deposits) are an important resource of medium-grade iron ore in the Hamersley Province of Western Australia. They are a special case of transported pisolitic ferricrust, differing from normal transported ferricrust only in the exceptionally high iron and low alumina content. The pisoids typically range up to 5 mm in diameter with abundant particles of ferruginised fossil wood up to 15 mm in maximum diameter preserved in the sediment. Field observations indicate that pisoliths are commonly initiated by the action of raindrops on iron-rich soil. Pisolites form by the impact of raindrops forming coated beads of ferruginous soil, which after dehydration obtain additional coatings during successive showers. Thick deposits of pisolite that are transported and deposited primarily by sheetwash form in the distal regions of the pediment. A size range limited to particles that may be transported by extremely shallow water characterises the abundant fossil wood fragments. The absence of fine sedimentary layering in pisolitic iron ores is explained by the action of soil-forming processes after deposition, while the major coarse bedding features derive from successive erosional and depositional events in the evolution of the pediment. They are not deposited in channels by rivers which, in arid to semi-arid conditions, typically deposit quartz sands and gravels with characteristic point bars and current bedding, abundant ferruginous granules, but rarely pisoids. However, they may fill abandoned river channels.

Jan 1, 2007

Modern plate tectonic reconstruction of Mexico and Central America shows that the southeast-extend ing Precambrian backbone of Mexico, together with the east-flanking accreeted Huastecan (Appalachian-Caledonian) orogenic belt, are geotectonic elements practically absent in Central America, except west-ern and northern Guatemala and Belize, and contrib-uted little to the mineral potential of the entire region.The gradual accretion of the Cordilleran oro-genic belt took place against the western-south-western margin of the Precambrian backbone, and its consolidation required several tectonic events from the medial(?) Paleozoic to the end of the Mesozoic. The striking features of this "long-lived" orogenic belt are the massive sulphide min-eralization in the upper Paleozoic eugeoclinal as-semblage, the widespread gold occurrence in quartz veins in the lower Mesozoic volcanics and related intrusives, the carbonate-hosted silver-bearing lead-zince deposits of the Mississippi Valley-type (or Pine Point-type) around carbonate banks within the Lower Cretaceous back-arc miogeocline, that de-veloped over the Precambrian backbone and deeply-eroded Huastecan orogenic belt, the massive sul-phide (Pb-Zn) deposits in the Upper Jurassic-Lower Cretaceous sequence, transitional from miogeocline to eugeocline, which carry high grades in silver, and the iron deposits in this transitional facies, which are described in the literature as related to dioritic intrusives of Late Cretaceous age. Central America, south and southeast of the Mota-gua-Polochic fault system, forms part of the in-ternal zones of this orogenic belt.

Jan 1, 1990

In recent years a large number of Horizontal Belt Filters have been installed in the Australian mining and chemical industries. This paper deals briefly with the general background and advantages leading to the selection of this type of filter. Several different applications are described and particular reference is given to the simplification of the fines treatment circuit at the South Bulli Coal Washery.

Jan 1, 1989

Nickel laterite approximately 40% of the remainder caning deposits. ores are the source of the world's nickel with from sulphide ore Although laterite ores are near the surface and cheap to mine they require significantly more energy to treat than sulphide ores. The escalation of oil prices comiencing in 1973 meant that nickel laterite refineries using oil as an energy source were placed at distinct disadvantage relative to sulphide refineries or those with coal derived energy. The Queensland Nickel refinery commenced a construction programme; in 1980 to allow ore drying and power generation to be converted from oil to coal. Since late 1981 ore drying has been undertaken using heated air from two moving grate spreader grate stokers. The changeover from oil to coal drying proceeded without process disruptions. This paper discusses the plant changes required to allow the receipt of coal and the operating performance obtained from the coal fired air heaters.

Jan 1, 1987

By Liu Q, Siefken T. C, Misra V. N

The bubble size was measured in a laboratory flotation column. The effect of variables such as air flowrate, frother dosage and type, pulp density, particle size and water column height on the bubble size was investigated. The results show that an increase in either air flowrate or pulp density cause the bubble size to increase, while increases in water column height, frother dosage, surface tension or solid particle size cause the bubble size to reduce. Among the frother types tested, MIBC was found to be the most effective in reducing the bubble size.

Jan 1, 1992

The problems arising in the excavation of hard rocks with the use of mechanical tools consist chiefly in a slow advance rate accompanied by an intensive wear due to the toughness and abrasiveness of the rock. In order to allow the further extension of mechanical excavation beyond the limits of the presently available technology, the assistance of waterjet aiming at improving the performance of the equipment while reducing the wear rate of the tools, has been recognised as one of the most interesting technical solutions. The paper illustrates the improvement of the performance of both disk cutters and picks obtained with the waterjet assistance at the Waterjet Laboratory of the University of Cagliari on a medium-hard rock.

Dec 6, 2010

By McNay L. M

Two field studies to monitor fill pres sures and vein-wall deformation were conducted in mines of the Coeur d'Alene mining district in Idaho. Both operations employed cut-and-fill mining techniques in nearly vertical veins aver- aging 10 feet in width, and backfilled with classified mill tailings. Hydraulic pressure cells were used to measure transverse, longitudinal, and vertical pressures within the backfilled stopes. Rock bolts extending into the manways and mechanical closure devices were used to monitor vein-wall convergence. Continuous recorders were used with selected pressure cells to prolong the life of the installation. Transverse pressures in excess of 600 psi and stope wall closure up to 22 inches were re- corded. Closure rates were higher at midheight of the stope than they were near either sill, indicating that the vein walls react similarly to a beam supported on each end.

Jan 1, 1973

During the past 18 months several import- ant hydrocarbon discoveries have been made in the Dampier Sub-basin, which is a sedimentary area lying entirely offshore from the Precambrian Pilbara Block in the southern part of 'he Northwest Shelf of Western Australia. This sub-basin is a major sedimentary downwarp forming a northern extension to the Carnarvon Basin. This extension is bounded to the north by the De Grey Nose, separating it from the Beagle Sub-basin. To the south the Dampier Sub-basin merges with the Barrow Sub- basin. Extensive seismic data combined with results from exploration drilling show that the Dampier Sub-basin is a complex depositional basin containing over 20,000 feet of sediments which are mainly Triassic to Recent in age. Tectonically the sub-basin can be divided into seven main structural elements. In a northwest to southeast direction these are the Rankin Platform, the Kendrew Trough, the Madeleine- Dampier Trend, the Lewis Trough, the Legendre- Rosemary Trend, the Enderby Fault Zone and the broad Pilbara Shelf. Permian sediments were encountered in only one well drilled to date in the sub-basin, but Triassic and younger sediments are extensive. The section consists initially of 'hi -_D 7 ri ,~ ~, , i , Derived

Jan 1, 1973

By Tarrant GC

Cement and resin encapsulated tendons are widely used in the stabilisation of mine roadways. One of the main factors in controlling the efficiency of the reinforcement is the ability of the tendon to generate load in response to rock deformation. The analysis of field data from instrumented reinforcing tendons complimented with extensive laboratory investigations have more accurately defined the mechanisms by which load generation occurs. The role of reinforcing tendon profiles, hole geometry and encapsulation medium properties in controlling the reinforcement stiffness and capacity are discussed. The results of the investigation have implications in both the design of rock reinforcing systems and the optimisation of encapsulation mediums and tendons.

Jan 1, 1992

A simulation model of the load and haul process where the loader cycle has been subdivided into its individual components is used to consider the benefits derived from improved drill and blast methods. Field data from a Hunter Valley mine is u

Jan 1, 1998