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Data logged on mineral beneficiation processes during normal operation are analysed using time series (correlation and spectral) methods to identify the dynamics of the processes for on-line computer control. Recursive least squares estimation techniques are used to identify parametric models for a cassiterite flotation circuit and a coal washery. Identification problems such as the determination of model order, process time delays and the 'contamination' of the data by process recycle streams (feedback) are discussed. Typical results are presented in which optimised models are identified from data logged during normal operation.

Jan 1, 1985

By Lee RJ

A significant basemetal province is recognised in the southern part of the Bonaparte Basin, Western Australia. Epigenetic stratabound carbonate hosted Pb-Ag-Zn mineral- isation occurs in dolomites of Tournasian age within a marginal marine transgressive carbonate and fine grained clastic sequence, spatially overlying the lagoonal facies of a Late Devonian reef complex. The deposits comprise coarse grained sulphide mineralisation characterised by high Pb:Zn ratios (10:1) and high silver (50 g/t) content. They occur at shallow depth, are flat to moderately dipping, and form a discontinuous mineralised trend at the margin of the Sorby Platform, which flanks a Precambrian basement high. Host rocks are predominantly sedimentary breccias and dolomitised footwall carbonates associated with a significant local unconformity transgressed by a siltstone cap rock sequence. The deposits are structurally related to synsedimentary growth faults, local basement highs and tensional en-echelon breccia systems. Fluid inclusion studies have concluded that mineralisation was deposited from a low temperature (85¦C-115¦C) saline ore forming solution. Lead isotope work reveals a Precambrian genetic source of the lead. Locally remnant textures after sulphates are recognised within the host sequence together with common bitumen and oil shows. Reduction of sulphate to H2S was possibly facilitated by either bacteria. activity, or by residual hydrocarbons which acted as a reducing agent. An alternative source of H2S may have been afforded by the thermal degradation of hydrocarbons. A 'mixing' genetic model is proposed for the mineralisation, which conceives the expulsion of metal enriched basinal brines followed by their precipitation as sulphides after mixing with locally derived reduced sulphur solutions at relatively shallow depths in their structural/stratigraphic sites of ore deposition.

Jan 1, 1986

By Bhattacherjee A, Makesh S

Mechanised sub-level stoping is one of the most widely accepted stoping practices followed in base metal mines in India. As a general practice, blast-scheduling of rings in these stopes is done either heuristically or randomly which leads to a high fluctuation in ore grade when drawn and delivered to the mill. In this paper, dynamic programming has been investigated as an optimisation technique for optimal blast-scheduling of rings. A microcomputer based dynamic programming algorithm has been developed in C language which runs under the UNIX environment. A case study based on Indian mine data is presented to demonstrate the application of the dynamic programming concept and use of the developed software. It is concluded that dynamic programming can be used as a production planning tool in Indian mines practicing sub-level stoping and following heuristic/random approaches for blast-scheduling of rings.

Jan 1, 1995

The O.K. deposit occurs within a belt of cherts and spilitised basic volcanics near the western margin of the Hodgkinson Province. The tabular to lenticular shape and gross conformability of the ore bodies; the common occurrence of colloform, framboidal and banded textures in the ores; the lack of significant alteration adjacent to the massive ore horizons and the apparent restriction of stockwork mineralization to the foot-wall side of the massive ore zone at the O.K. mine, all favour a syngenetic origin for the massive sulfide bodies. Furthermore, the micro- structural evidence suggests that the ores have undergone the same deformational history as the country rocks. The invariable association of the ores with spilites; the S isotope values and Co-Ni contents of the pyrites, together with the primitive metal assemblage (Fe, Cu, minor Zn) strongly favour a basic magmatic source for the sulfides. It is suggested-that the sulfides were probably precipitated sub aqueous- ly during a hiatus in volcanic activity. The O.K. deposit is of the cupreous pyrite variety, but unlike other well known occurrences of this type, it does not con- stitute part of an ophiolite complex. While the host volcanics exhibit strong ocean floor tholeiitic affinities, no associated ultra

Jan 1, 1978

By Aspinall T. O, Bell L. C

Increased awareness and stricter enforcement of regulatory requirements for adequate rehabilitation of surface mining sites has made environmental planning an essential part of strip mine planning. Rehabilitation is site specific and should be based on data which relate to that site. Cost-effective spoil pile design to minimise erosion is an important part of rehabilitation. Spoil pile design is an integral part of strip mine design. QCT Resources Limited has provided a postgraduate scholarship toward research in this area. The controlling factors of spoil pile design are post-mining land use, drainage requirements and degree and rate of erosion. The extent to which mine design is controlled by these factors is determined by regulatory requirements. To plan acceptable rehabilitation programs, erosion processes must be accurately modelled, and a range of erosion prediction models are available. Useful prediction models can be placed in two categories with the first category containing soil loss prediction models which can be used to predict the amount of soil lost from an area over a short or long term basis. Models in this category include the Universal Soil Loss Equation (USLE), Water Erosion Prediction Project (WEPP), Griffith University Erosion and Sedimentation System (GUESS) and Chemical, Runoff and Erosion from Agricultural Management Systems (CREAMS). The second category contains topographic evolution models which give an indication of the long term morphological development of a formed surface subjected to erosion processes. Models in this category include "Topog", Willgoose's Physically Based Catchment Evolution Model and Areal Nonpoint Source Watershed Environment Response Simulation (ANSWERS). The USLE has been used in the agricultural field for soil loss prediction. To apply the equation to mine sites in Central Queensland, it is necessary to understand the factors affecting erosion at the sites. This understanding should allow the variables of the equation to be quantified. The rainfall factor applied in the USLE is independent of engineering design or soil management techniques. The factor of spoil erodibility is dependent on the material's physical and chemical properties and can vary from site to site. In the equation, the topographic factor, cover and management factor and conservation practices factor can be varied by design to reduce erosion on rehabilitated areas.

Jan 1, 1991

Diamonds have been known in Australia for many years, especially in association with alluvial gold and tin occurrences. Exploration for primary sources in the Kimberely area of Western Australia has been carried out since 1968, culminating in the discovery, in 1979, of the Argyle Kimberlite No 1 (AK1) kimberlite pipe. Various techniques have been used in the search for diamonds such as geologic interpretation, aerial photography and Landsat, soil geochenical techniques, geophysics, and stream sediment sampling. Stream sediment sampling, a method developed in South Africa, using the detection of indicator minerals derived from kimberlites in gravel samples, has had wide application and success in Australia. Nevertheless, although Australian diamond bearing kimberlite and lamproite rocks contain some of the classic indicator minerals, their concentrations are generally much lower than in South Africa and Russia. Despite this paucity of indicators, stream sediment sampling is still the best known and most commonly used method of diamond prospecting in Australia. Small samples are treated by hand but larger samples require the use of diamond pans, jigs or heavy media separation plants. Each of these methods has advantages and disadvantages. The final concentrate is passed over a grease table or subjected to x-ray sorting.

Jan 1, 1984

This paper is written as a supplement to that of Edwards, Baker and Knight on "The Geology of the Wonthaggi Coalfield" 1, the West Area pit being in an early developmental stage at the time of their paper. The thin seams to the west of Dudley Basin 2 had beenknown for many years but it was not until 1935 that it became necessary to work them. The West Area Pit came into production as Dudley Area Pit approached exhaustion in 1937. From available information it was estimated that early work would be in a 36in. bottom seam. The present top seam was not included in the reserves, but it was to be extracted where it proved thick enough for economical working.THE SEAMSEdwards, Baker and :Knight (1944) had insufficient information to correlate positively the West Area seams with those in the Dudley Basin. Their opinion was, however, that they were a westerly extension of the Bottom Seam. Since then the driving of the present north-east heading towards No. 4 Bench McBride Tunnel has established that the West Area seams are those worked as Bottom Seam in the Dudley Basin. West Area Top Seam is a seam that occurred above the Bottom Seam in the Dudley Basin. Only sporadic attempts have been made to work it in Central Area, because 30in. was considered an economic minimum height until recent times. This seam should not be confused with Top Seam, Dudley Basin, which lies some 300ft. above the bottom seam measures and except in isolated areas over deeper workings has been eroded away in West Area.

Jan 1, 1953

By Crosby N. R

The design of mine openings and the assessment of their reserve are processes ihicl, require the routine manipulation of considerable amounts of data. A number of computer programs have been assembled to operate in a mini computer in order to provide some mechanical assistance for these processes. The system responds to plain language commands. which allows mining engineers to compute the reserves for a number of possible mining outlines, on an interactive basis. Methods of numerical analysis were used in preference to statistical or qeostatistical techniques.

Jan 1, 1977

By Chander S

Properties of surface films on chalcopyrite and pyrite differ due to variations in the mechanism of oxidation of the two minerals. In the case of chalcopyrite the first step in the oxidation is the release of iron as ferric ions, which hydrolyse depending upon conditions prevalent in solution. The iron oxide/hydroxide layer formed by hydrolysis of ferric ions is quite porous and easily detachable from the surface of chalcopyrite. When the surface oxide layer is detached a sulphur-rich layer is exposed making chalcopyrite hydrophobic. The thickness and properties of the sulphur-rich layer determine its flotation response, both in the absence and presence of collectors. In the case of pyrite, on the other hand, iron is released as ferrous ions which require much higher pHs to hydrolyse. These ions remain adsorbed on the surface of pyrite making the surface hydrophilic. When the iron species are complexed with chelating agents such as ethylene diamine tetra acetic acid, pyrite was hydrophobic. Siderite forms in the presence of carbonate ions, which might be present in several flotation systems. Siderite nucleated on isolated sites at the surface. The presence of such a precipitate is likely to influence the interaction of pyrite with various reagents thereby altering its flotation behavior. To determine the mechanism of oxidation, kinetics of oxidation of chalcopyrite and pyrite was studied using several electrochemical techniques, namely, cyclic voltammetry, polarisation and impedance spectroscopy. Floatability of the minerals was investigated by measurement of contact angles on mineral electrodes and by Halimond tube flotation. Impedance spectroscopy was especially useful for estimating various properties of surface film for both the minerals. Properties such as charge transfer resistance, porosity, and capacitances of the surface films on the two minerals are compared under several conditions of oxidation. These properties were found to be a strong function of the rate and the extent of oxidation.

Jan 1, 1993

By Culshaw MG, Deaves AP, Bell FG

The accurate prediction both of the water ingress into sub-surface excavations and the nearby groundwater pressures is of fundamental importance to the control of the stability and flooding of tunnels or mines constructed below the water table. Predic- tions are usually based on laboratory and in situ permeability determinations together with observations of groundwater conditions in boreholes. Although established theoretical methods provide a basis for prediction, the actual ingress depends on many factors. The objective of this paper is to explore the geological controls on groundwater conditions, and the available methods of prediction of both groundwater flow and pressure are outlined. Salient points are emphasised by reference to a case history involving the construc- tion of a tunnel in a faulted and mixed sequence of sandstones, siltstones, shales and coals. Water ingress quantities have been monitored for a variety geological and geotechnical conditions including heavily faulted and mine disturbed ground. The overall results are discussed with reference to the relevant hydrological and geologi- cal conditions in terms of the geological structure, lithology and rockmass condition as well as the construction methods.

Jan 1, 1988

By Brimblecombe P

Morwell Open Cut is a continuous mining operation employing 5 buck- etwheel excavators, I bucket chain excavator and 54 conveyors. The combined bunkering capacity at both client Power Stations represents less than 12 hours maximum coal demand. This creates an extremely dynamic operating environment, which is further complicated with significant variations in both excavating and transportation plant capabilities. To achieve set objectives, including- I adequate reserves, 2 coal supply reliability, 3 cyclic plant maintenance, 4 minimal cost of coal, scheduling of the operation requires constant monitoring and reappraisal. Investigations are in progress to develop a computer based scheduling tool capable of simulating the complex operating environment. A review of computer scheduling packages currently available within the State Electricity Commission of Victoria has found limitations making most unsuitable for the task. The type of package found to be most suited is a knowledge based system ('Expert System')capable of operating within a set of rules defined by the user. Work is proceeding on the development of a knowledge base to test the effectiveness of Personal Computer based `Expert Systems'.

Jan 1, 1989

By Koppe J. C

This study presents the procedure of mine modelling and reserve evaluation by means of statistics, computer interpolation methods and aerophotography interpretation. All data are from Carbonifera Treviso, Laura Muller City, Santa Catarina State, southernmost Brazil. From 22 bore holes and nine trenches opened in the coal seam outcrops, a data base including level references and thickness of all rock formations was created.Using this information, basic statistic analysis was carried out, showing that there are three different populations (three modal distribution). These populations defined three geological blocks with different characteristics of overburden removal and mining methodology. This mathematical approach for analysing geological data is very important for correct mine planning and complementary prospection.

Jan 1, 1993

This paper investigates the adequacy of current gas monitoring techniques to adequately detect spontaneous combustion in underground coalmines. Despite being in the 21st century spontaneous combustion continues to occur in underground coalmines sometimes being detected only at a very advanced stage. Control of the incident is often then very expensive and time consuming. The adequacy needs to be assessed not only from the point of view of the analysis technique be it tube bundle, gas chromatograph or real time sensor but also the number, location and sampling frequency of the monitoring locations. Recommendations are made to optimise monitoring processes and recognise limitations of current techniques.

Jan 1, 2005

With mining development on hold and other underground works in a slowdown, the develop- ment of nuclear waste repositories takes center stage on the American rock engineering scene. Three repositories for commercial spent fuel -- in salt, tuff, and basalt -- are in the phase of site characterization and conceptual design, and one pilot project for defense high-level waste in salt is under construction. A repository design for crystal line rock has recently been postponed. Because of strict quality assurance requirements throughout design and construc- tion, and because of the need to predict and ascertain in advance the satisfactory perfor- mance of the underground openings, much intellectual energy has been expended to analyze underground openings in the unusual circumstances of the repository environment. In the long term, these efforts will lead to an improved understanding of rock behavior and improved methods of underground analysis and design. For the shorter term, a formalized ground control plan was developed, the princi- ples of which may be applied to other types of projects. This paper summarizes the status of underground design and construction for nuclear waste repositories and presents some details of the ground control plan and its individual elements.

Jan 1, 1987

By Toguri JM

A solid electrolyte technique has been used to measure the activity of cobalt in liquid cobalt-gold alloys containing between 0.085 and 0.50 mole fraction of cobalt, and for temperatures from just above the liquidus to around 1550 K. The system exhibits positive deviation from ideality, both in the activities of cobalt and gold, and in the enthalpy and excess entropy of mixing. The results agree with previous measurements using a Knudsen cell - mass spectrometer technique, but differ from those reported for a gas equilibration method. The data have been used to calculate the activity coefficient of cobalt oxide in silica saturated iron silicate slags and to express the solubility of cobalt in such slags as a function of cobalt activity and oxygen pressure.

Jan 1, 1984

By Rospigliosi RT, Krouse HR

The San Vicente stratabound zinc-lead rhythmite deposit, Peru, is hosted in carbonates of the Late Triassic - Early Jurassic Pucara Group. These strata were deposited in a large, shallow water, carbonate platform which extended nearly continuously for 150 kilometers (north-south) in the eastern part of the Pucara basin.The distinctive sulfide-bearing rhythmites occur in three dolomite units which, from bottom to top, include the San Judas horizon with one sulfide-bearing manto; the San Vicente horizon with seven sulfide-bearing mantos including the main ore horizon; and the Alfonso horizon with three sulfide-bearing mantos. The dark gray sulfide-bearing dolostone layers range in thickness from a few millimeters to a few centimeters and contain variable amounts of carbonaceous material, pyrite, quartz, fine-grained sphalerite and galena. They are bordered on each side by selvages of yellow to red-brown coarse-grained sphalerite containing minor amounts of galena. Coarsely crystalline white or gray sparry dolomite is found between the coarse-grained sphalerite layers. Although commonly stratiform and uniform in thickness, the dark layers curve, "pinch out," coalesce, and form "islands" and "peninsulas."Mineral replacement textures, the paragenetic sequence, and presence of sparry dolomite, bitumen, intraformational breccias and isotope data support a hydrothermal replacement origin by metal-bearing solutions that deposited the ore and related minerals in space previously occupied by dolomite and evaporite minerals. The alignment of the Zn -Pb deposits, and at San Vicente the orientation of the mantos, the spatially and temporally associated igneous sills and the tourmaline-bearing sandstone support hydrothermal mineralization driven by a magmatic heat source in a tensional regime.

Jan 1, 1990

By D FitzGerald

A critical component of any new tunnel design in a complex geological setting is the development of an integrated three-dimensional (3D) geology model with a full set of geotechnical properties of the rocks present. A novel means of predicting the geology based upon sparse observations of structural geology at the surface and from drill holes has been developed and used in several major tunnel studies in Europe.An example of this is the Lyons-Turin twin rail tunnel which is still in a development phase. This tunnel has been in planning and development for over 15 years already. An important aspect of this work is to characterise geological uncertainty along various possible tunnel paths as an input into early design optimisations for time, cost and risk avoidance strategies. Once the tunnel works commence and more detailed geological data is collected by daily mapping, progressive refi nement of the geological model is desirable; geological conditions still to be encountered can be more accurately predicted. Faults and their offsets, dykes, geological unconformities, folding, as well as standard sedimentary processes are all correctly modelled in the software. It is important to allow for seamless interchange of geological models at various scales with CAD workflows so that sufficient detail can be readily accessed at the required scale. Also, the proposed tunnel in its correct geometry can become a ‘section’ in its own right. Progressive detailed local geology models in the vicinity of the advancing head are created from the regional scale work by cutting and pasting a starting model, then adding all the extra detail for the required engineering geology work.For all rocks, most standard geotechnical quantities such as sonic velocities, Young’s modulus and Poisson’s ratio are handled. These and any other phenomena from borehole observations can have variograms calculated and stratigraphically constrained estimations made in a least biased geostatistical manner, in advance of the tunnel. RQD, or a prediction of rock fractures, is handled by the faulting and folding modelling facilities. This is probably the more interesting issue to pursue, as the fractal nature from small scale fractures and joints, to large-scale faults, can now be characterised more convincingly.

Mar 8, 2011

By Greenhalgh L. P H

The opportunities offered by an increasingly volatile world invite the international consultant or engineering services contractor to broaden attitudes, diversify interests, expand capabilities, retain and develop specialist skills and base judgements upon sound principles and solid experience. The wide-ranging scope of this review reflects such a change but the topics of discussion are not intended to be exhaustive or to detract from many other current developments.The subject of environmental protection, effluent control and pollution prevention is a primary consideration in the application of many mineral processing technologies but is not covered here. There is an array of developments relating to noxious gas emissions and toxic wastes and the paramount importance of this matter justifies comprehensive conferences dedicated solely to the application of suitable measures. This review concentrates therefore on the main stream processing techniques for the primary recovery of values.

Jan 1, 1993

A major tool in the search for petroleum is reflection seismic mapping. The period which has seen most of the exploration in Victoria is also one which has seen major advances in this technology, from 1963 try present day. Seismic mapping can be divided into three interlinked areas - acquisition, processing, and interpretation. In acquisition the major changes have been from an explosive energy source in 1963 to gas exploders in 1968 and airguns in 1970. The number of recording channels has increased from 24 to 192, with digital recording introduced in 1966, and floating point recording in 1976.

Jan 1, 1982

By Dhawan AK

On 8 July 1993, a landslide of about one million cubic metres of rock blocked the river Satluj near Sanjay Vidyut Pariyojana - Bhaba project and caused flooding into the Bhaba Power House (120 MW) resulting in suspension of power generation. The concerned authorities desired an early removal of the blockade by an underwater blasting operation into the over topping water to reduce the water level at the blockade and resume power generation in the power house. In the absence of underwater drilling, it was essential for the blasting technique to be used where no cavity to confine the explosive was required. For this reason mud capping and plaster shooting with directional throw were used and additional specially fabricated mild steel pipe charges were used under high current for an underwater trenching operation. By employing these techniques the river blockade was removed up to the required depth and on 8 September 1993 the Power House resumed the power generation.

Jan 1, 1995