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By Channon W, Dube M, Makwana M, Kerfoot D. G

In early-1995, the Bindura Nickel Corporation commissioned a pressure leach plant at its Smelter and Refinery complex located in Bindura, Zimbabwe. The novel pressure leach process was developed by Sherritt to treat the nickel-copper sulphide residue produced from the original atmospheric leach circuit. The process extracts essentially all the nickel from the nickel-copper sulphide residue under non-oxidising acid pressure leach conditions, thereby producing an upgraded copper sulphide residue suitable for smelting and refining to electrolytic copper. The commissioning of the pressure leach plant was relatively smooth and design conditions were achieved within six weeks of operation. This paper presents a brief description of the process development and the plant design, followed by highlights of the plant start-up activities and summary of the plant performance.

Jan 1, 1996

By James D

Fletcher Challenge Limited through its subsidiary Grampian Mining Co Ltd has carried out an ore evaluation of one of New Zealand's largest known deposits of ilmenite located at Barrytown on the west coast of the -South Island, New Zealand.The ilmenite is located in a beach sand environment which has previously been mined for gold. Two analytical techniques were developed to quantify the resource. Considerable difficulty was experienced in this phase of the evaluation due to the presence of major inclusions within the ilmenite grains. Wet and dry concentration circuits, utilizing spiral, wet magnet, high tension and plate electrostatic separators have been G47designed to produce ilmenite from the ore. Studies to utilize the titanium content of the Barrytown ilmenite have been made. Recent work has been directed towards a titanium dioxide pigment process.

Jan 1, 1986

This paper discusses the recently com- pleted TBM-driven pressure tunnel at the Sand Bar Hydroelectric Power Project. The Sand Bar Project is a diversion scheme situated on the middle fork of the Stanislaus River in the Western Sierra Nevada, California, U.S.A. As part of the project, a 5.6 km long and 3.71 m diameter unlined pressure tunnel was bored by a Jarva TBM at the average rate of .37.5 m/ day. This report deals with construction aspects of the tunnel, including TBM performance, lining design, and remedial support measures. Correlations between TBM performance, geologic conditions, and rock properities are made, and the Contractor's mode of operations are discussed. Advance rate prediction, and the impact of these excellent advance rates attainable in hard rock using the new machines are discussed.

Jan 1, 1987

Existing fluid flow techniques may be readily applied to the design of ranges for seam gas drainage. The Reynolds number characterises the flow regime within the pipe and it can be used in conjunction with data on absolute pipe surface roughness to determine the system friction factor. The application of the solution to the isothermal compressible flow equation utili- sing Moody friction factors and the concept of equivalent length of pipe for fittings and valves provides a practical method for sizing gas ranges. The physical capacity of a range can be decreased by the existence of significant quantities of water in the range and also by the ingress of air into the system at poor pipe joints etc. Both problems can be elimin- ated by adequate attention to design detail.

Jan 1, 1982

By Warren R

Croesus Shaft is one of two operating shafts on North Kalgurli Mines Limited's Fimiston lease.At the cessation of gold mining in 1974, the workings at Croesus were allowed to flood. Large quantities of deslimed mill tailings used in filled stopes were washed into the shaft and surrounding drives, making re-access very difficult. The shaft has been desludged from the 9 level to the 15 level, and a loading pocket installed below the 14 level. A vacuum lift unit was installed underground to facilitate the removal of the slime and spillage.Stoping at Croesus was hampered by poor drainage, pumping, and shaft availability. These difficulties have been overcome by utilising an open stoping system for the relatively steep, narrow, high grade stopes. Open stoping has proved to be effective and economic.

Jan 1, 1985

Structural Controls Interpretation of regional aeromagnetics, radiometrics and satellite image data has identified three structural domains (fig 2): The Fairyland Domain: a general N - S structural trend. The Cracow Domain: a general NW - SE structural trend. The Bald Mountain Domain: a general N- S structural trend. Known mineralisation is confined to the Cracow Domain in which there occurs two major NW - SE trending fault zones. The Cracow Fault Zone (CFZ) and the Immy Creek Fault Zone (ICFZ). Enhanced detail of the CFZ (fig 3) shows three main structural trends within it: NW-SE structures which include the mineralised White Hope South fault zone and the Golden Mile fault zone. NE-SW structures which have an influence on mineralisation in the Orange Creek, Fernyside and Golden Plateau areas. N-S structures comprising several major structural zones.

Jan 1, 1990

By K E. Barns, P J. Sharman, S A. Thomas and

This paper presents the development of a regrind facility design at BHP BillitonÆs Leinster Nickel Operations (LNO) in Western Australia. The recovery opportunity was identified from an analysis of plant operating data together with scanning electron microscope (SEM) measurements on relevant tailings streams from LNO. A laboratory procedure was developed to determine the potential recovery improvement of installing a regrind facility at LNO. The last step in formulating the process flow sheet and defining the process design criteria was to construct and operate a pilot plant, which incorporated four banks of flotation cells and an Xstrata M20 Isa Mill. Pilot plant on/off trials were used to define the expected metallurgical benefit. A prefeasibility engineering design and cost estimate was completed. Following a successful internal business evaluation, a feasibility study is currently underway.

Jan 1, 2007

The patented "Epytensic" pump of Minnovation Ltd, a multiple piston pump, is used widely on shearer loaders and by partial high pressure watcr jet cutting strategically in relation to cutter picks not only improves cutting rates, but saves power and increases the life of gearboxes and picks, as well as improving dust suppression. The "Face Side Pump", also a piston pump, located on the ranging arm gearhead has advantages over gateroad pumps and shearer body pumps. The "Extraction Drum", hydraulic air mover system, linked with the above innovations and high pressure water, have further advantages in methane and dust removal. Some modifications providing these systems need workshop applications but most are possible underground with minimal changes to shearer profiles and advantages of minimising hosing, along with the other advantages stated.

Jan 1, 1991

By Rosmus P

Improper use of auxiliary ven- tilation units during heading operations may often result in the appearance of hazardous methane accumulations. This is the case especially when roadways are ventilated by a combined system with a short sucking pipe at face end performing as the dedusting installation. Uniform air inflow to the face end facilitates sucking off the dust clouds and creates conditions favourable for formation of local methane accumulations. The highest methane concentration occurs in the cutting zone between the rock cut and the pipe inlet, under the roof and by, the sidewalls. Permanent monitoring of methane concentration at face end employs methane sensors. The most important are: one on the road- header's boom behind the cutting head, and one at the air outlet from the dedusting installation.

Jan 1, 1988

By H Austrheim, A K. Engvik, A Putnis

How aqueous fluids move through rocks and minerals is a question of possible pathways and mechanisms. Existing pathways such as fractures and grain or mineral boundaries provide obvious channels for fluid movement. We show how minerals reactive in the presence of an interfacial fluid can be replaced by new product phases through a process of interface-coupled dissolution-reprecipitation. A resulting porosity in the new phase provides a new pathway for fluid movement and therefore mass transport through the mineral, which progressively reacts at a moving interface. Eventually fluids of new and changing composition can pass through originally solid minerals and move on further, taking remobilised elements with them, to be reprecipitated whenever the chemical and/or physical conditions allow. One such example is albitisation of rocks associated with mineralisation.

Jan 1, 2008

By Campbell R

The use of a 35mm non-metric SLR camera and an analytical plotter to prepare close range photogrammetric (CRP) plans of a quarry and open pit mine face is described. The plans, at scales ranging from 1:5 -1:1 000, were used to measure the orientation of geological structures and failure surfaces in the exposed faces.Details are provided on the equipment used and the field techniques. The method:ò is quick and relatively cheap to perform,ò allows the accurate orientation of specific geological features to be determined,ò provides survey results of suitable accuracy that may be used for detailed geotechnical analyses of pit wall failures,ò shows great potential as a rapid and accurate technique for monitoring changes in pit wall profiles with time.

Jan 1, 1990

This is a brief introduction of a sewer pipeline constructed with a pipe jacking method in combination with a 1 200 mm finished inner diameter tunnel boring machine developed for the first time in Japan. The pipeline is located under a national highway running through a densely built urban area and is 185.7 m long and 2.9 m to 3.7 m deep from the ground surface. The geological features along the pipeline show mostly slate and partly silt. The pipeline was constructed with a newly developed multi-application type tunnel boring machine equiped with a fluid transport system. The construction consisted of tunneling by a tunnel boring machine followed by pipe jacking operations. The excavated materials were dis- charged off the tunnel by a fluid transport System.

Jan 1, 1987

By Haskard R. W

A method of raising has been developed at Cobar Mines Pty Ltd's CSA Mine which has achieved advance of up to 6 m in a single blast and raises are now developed which have averaged 4.2 m per blast. The method is a form of Long Hole Raising and is applicable to short raises of less than 50 m length. Blast holes are column charged and initiated sequentially with short delay detonators (millisecond). The equipment used to drill the raising blast holes consists of normal production drilling rigs and accessories and no other special equipment is required. The method has significant advantages in rates of performance and fits neatly into production drilling and blasting schedules. The method is also far safer than any non-mechanical or conventional means of Raising.

Jan 1, 1983

By Guo H

The importance of using disc cutters for rock excavation is reflected by their wide application in hard rock cutting machines such as tunnel boring machines and raise borers. The forces involved in the cutting process are those due mainly to thrust and rolling forces and are greater than that required by cutting picks. An interesting feature of cutting with discs is the formation of surface crushing, surface and sub-surface chipping and primary crack formation. Experimental, as well as analytical, work has been carried out to determine the optimum spacing between the disc cutters to control primary crack orientation. Wedge bit indenters were used to simulate disc cutters. The paper concludes by proposing a new approach to rock excavation by hybrid cutting based on controlling the primary crack Orientation.

Jan 1, 1992

The original leases making up today's North Kalgurli Mines were developed by independent companies on an ad hoc basis. The major disadvantage which now arises is the varying levels of mining horizons. From Kalgurli Shaft in the south, through main Shaft and to Croesus Shaft in the north, there are three separate sets of levels. work has commenced to link the three areas with either common levels or new development which will facilitate common access and haulage via Main Shaft.Generally, the workings at North Kalgurli were established at the turn of the century. The introduction of techniques and equipment to bring the mine into the 20th Century has been difficult and slow. The general size of openings, a widespread workforce and complex ore distribution often make innovation and change more than a challenge.

Jan 1, 1985

By Weller KR

A study of high pressure rolls grinding of a number of Australian ores and minerals has been carried out using a pilot-scale machine with rolls 300 mm diameter and 70 mm wide. The results from this study have been used in conjunction with plant survey data to construct computer simulation models of various comminution circuits and these have been used to investigate options for incorporating high pressure grinding rolls into these comminution circuits. Possible rolls options for three of these circuits are presented, and likely energy savings over the existing circuits are discussed together with potential improvements in plant throughput and/or product sizing. A scale-up procedure for predicting full-scale machine performance from small-scale testing is described, and the effects of rolls operating conditions are also discussed.

Jan 1, 1991

The Kennedy Siltstone Open Cut provides graded rock for stope filling. Rotary drilling of 310 mm blastholes with a Gardner Denver GD120 is used, and the successful application of an equilateral triangular drilling pattern is described. Charging practices and the development of bulk slurry handling are outlined. Blast monitoring plays an important role in K.S.O.C. drilling and blasting operations. The proximity of nearby residential areas (1300 m) and the Mount Isa Airport (4500 m) necessitates special attention with regard to the minimisation of both air blast and ground vibration levels. The application and control of drilling and blasting parameters has had a direct bear- ing on success of the mining operations and also played an important role in reducing the disturbance to the community.

Jan 1, 1978

By Moon N. T, Torrance A. C

This study has considered the effect of mechanical shock on the resilience of the glass microspheres commonly used to sensitize an explosive emulsion. The damage to the glass microspheres caused by detonating cord, emulsion manufacture and the manufacture of the glass microspheres were considered along with the effect of sensitizer concentration on explosive performance. Reductions of up to 50% in the glass microsphere concentration of an emulsion explosive can result from poor initiation practice, such as the use of high strength detonating cord as downlines during initiation. Laboratory results suggest that detonating cords of strength greater than 3.5 g/metre should not be used as this can seriously affect explosive performance, particularly in small diameter charges. This reduced performance results from damage to the sensitizer elements and recrystallization of part of the emulsion phase.

Jan 1, 1990

With increasing depth of mining, geotech nical factors assume increasing importance in the design and operation of open pit coal mines. Dragline strip mines are particularly sensitive to stability conditions since the draoline is a relatively inflexible machine, particularly in relation to its limited dump- ing radius for overburden disposal. Geotechnical factors relevant to strip mine design include: 1. spoil pile stability 2. wall stability 3. floor stability 4. excavation characteristics 5. groundwater conditions A basic geotechnical investigation pro- gram for new mine feasibility studies is described. This includes: 1. terrain evaluation 2. geotechnical drilling and logging 3. geophysical logging 4. materials testing 5. seismic refraction traversing 6. groundwater studies Such a program will give an overall geotech- nical assessment of the site and highlight any areas which may require further, more detailed Investigations

Jan 1, 1981

The microstructures exhibited by ilmenite in its association with other oxide minerals have been the subject of a number of papers, the most comprehensive of which is that by Ramdohr. The following observations in some degree extend his conclusions. They are based upon a study of about sixty specimens of "massive" ilmenite and titaniferous ores from a number of wIdely 'scattered Australian localities. Specimens of this character proved much rarer than was expected. The collection was gathered together through the generous aid of the University Geological Departments, Geological Surveys, and Natural History Museums of the several States of the Commonwealth, all of which contributed such specimens of local origin, as they possessed. Special thanks are due to Dr. E. S. Simpson, of Western Australia, who made available several highly interesting specimens, together with his...

Jan 1, 1938