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By J Loeb, D Thornton

Blast movement measurement is a key component of grade control, enabling mines to carry all of the precision involved in locating ore blocks, through a chaotic blast, to production. A monitoring system was developed about ten years ago so that mine operation personnel can measure three dimensional movement in every production blast. Research has shown that blast movement is always highly variable with a significant non-deterministic component. The consequence is that modelling will be inaccurate and therefore optimal ore recovery can only be achieved by direct measurement of blast movement.Three dimensional movement vectors are measured at discrete locations in the blast. If blast movement is only measured at one location in a blast pattern, data is severely limited and has all of the inherent inaccuracies of modelling a variable population. It is intuitive that the accuracy of defining the post-blast ore block mark-ups are proportional to the number of movement measurement locations, however increasing the number of monitoring locations causes increases to the direct operating costs of the mine.A cost-benefit analysis is used to explore the optimal number of monitoring locations. Using the method described in this paper, an automated selection of the number and location of blast movement monitors are analysed against the value of recovered ore compared to the control, for each trial.CITATION:Loeb, J and Thornton, D, 2014. A cost benefit analysis to explore the optimal number of blast movement monitoring locations, in Proceedings Ninth International Mining Geology Conference 2014 , pp 441–450 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Erickson M. E, Smith C. K, Carswell J. T

Thirteen holes totalling 3200m were surveyed using a downhole time domain Geonics EM37 system at the 830 metre level within the CSA Mine, Cobar, New South Wales, in order to search for blind, electrically conductive sulphides at some distance from exploration drillholes. A significant off-hole conductor was detected in only one drillhole.Geophysical modelling and interpretation of the survey results indicated that this off-hole conductor was caused by a sulphide lens 30 metres from the drillhole at a hole depth of 220 metres.

Jan 1, 1990

By Hare S. M, Griffin P. T, O&apos

Chalcopyrite ore and converter slag treatment to produce copper concentrates is undertaken at the Copper Concentrator of Mount Isa Mines Limited. This concentrator was commissioned in May 1973, replacing the original No 1 Lead-Zinc Concentrator, for the processing of all chalcopyrite ore coming from Mount Isa Mine.Treatment of chalcopyrite ore at rates of up to 125 000 l/week is described here; the treatment of converter slag is described later.

Jan 1, 1993

By Ruschitzka C

The productivity and economic success of a German hard coal mine is attributed to the high productivity of a small number of operation points; however high rates of production are associated with increased gas emission at the working sites. Therefore modem high technology is required in order to reach the planned production rate, since high methane concentrations often cause unplanned breakdowns in operation. The optimised simulation of gas emission is a fundamental planning tool for mine design as well as for determining the potential of a coal deposit and has increased in significance over the last years. Methane-INFO enables the three-dimensional, graphical simulation of a working site taking account of different aspects such as the mine design, ventilation, production rate, geology, seam quality, gas exhaustion, etc. The following paper gives a short overview over the benefits of the discussed system.

Jan 1, 1995

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

Developments in furnace construction and design have been very rapid in recent years. Larger furnaces operating at high top pressures with much improved burdens are giving extremely high production rates. Modern scientific techniques and the use of computer control are contributing to these Rates.

Jan 1, 1972

By G Haywood

This paper presents the evolution of the planning, scheduling and mining practices at the Yilgarn Star underground. The paper will concentrate on the principals of æjust in timeÆ and the impact of such practices on mine planning and scheduling and subsequent development and production. The principals of æjust in timeÆ were developed to minimise the impact of creep and time dependent failure of the ground in the ore and hangingwall zones. These zones are characterised by altered schistose material with inherent weak rock strengths compounded, at depth, by the maximum principal stress of the virgin stress field approaching the UCS of the rock mass. Yilgarn Star underground has and continues to develop the æjust in timeÆ methodology to ensure the continued viability of the mine. The mine continues to use longhole open stoping mining methods to ensure high levels of productivity with minimal dilution and at an acceptable cost of production.

Jan 1, 2002

By I Grewal, B Klein

The Knelson Continuous Variable Discharge (CVD) is a continuous centrifugal gravity concentrator for high-mass yield recovery applications. It has four operating variables that enable control of mass yield, product grade and recovery namely: fluidisation water, bowl speed, pinch valve open time and pinch valve closed time. Plant testing of a pilot scale Knelson CVD6 was conducted to evaluate the effects of operating variables on mineral separation. The analysis of operating variable effects has provided a framework for the development of operating guidelines for the CVD.

Jan 1, 2001

Tomago sandbeds is an unconfined coastal aquifer located 20km. north of Newcastle in New South Wales, Australia. These sandbeds extend over an area of about 130km. The average aquifer depth is about 20m. with a mean transmissivity of about 400sq.m/day and a specific yield of about 0.2. The city of Newcastle and surrounding areas derive water from Tomago for potable purposes. The average extraction being about 50 ML/day. The iron value of the ground water varies between 5 and 15mg/1. This iron is removed by a conventional water treatment plant using Alum. The aquifer whilst principally quartzose also contains deposits of heavy minerals like rutile, zircon, ilmenite, etc., The mineral sand mining has been in progress at Tomago since 1972. Mining is carried out in a con- structed pond with a water depth of about 5m. on which is floated a suction cutter dredge that moves across the front of the pond using a water jet to entrain the soil from the ground surface to the bottom of the mineralised zone. Effect of mineral sand mining on ground water quality, particularly iron, was the subject of intensive investigations undertaken at Tomago since 1970. The effect on water quality was studied by collecting and analysing water samples from network of observation wells established during the period of mining. Water samples were collected about 4-5 years prior to mining and analysed for iron, sulphate, chloride, pH, etc., After mining the observation wells were re-established at the same locations and water samples were collected and analysed for at least 5 years after mining. Water samples collected from majority of the observation wells indicate an increase in iron levels. The level of increase is very site specific. The increase in iron is also

Jan 1, 1987

The paper describes the geology, structure, stress, gas and strata geomechanical properties for Leichhardt Colliery and their reactions to mining.

Jan 1, 1986

By Mitchell M. A

The steeply dipping Mammoth orebody is mined by Gunpowder Copper Limited using a sub- level uphole bench stoping method at a mining rate of 350 000 tonnes per year. of three per cent copper ore. Access to the mine, is provided by 1 in 9 decline which spirals in the footwall connect-, ing all the sublevels, thus maximising mobility and accessibility of trackless mining equipment Sublevels are driven in ore off cross- cuts from the decline every 15 metres vertic- ally. Sublevel drives are stripped out to widths up to 18 metres before cutoff slots are mined at each end. A two boom fan drilling jumbo is used to drill inclined rows of holes to the floor of the sublevel above. Two or three rows are fired at a time which allows broken ore and remnants from the level above to be mucked out by rubber tyred LHD equipment to the brow. Ore widths of up to 80 metres are en- countered at lower levels where ring drilling from longitudinal drill drives will break ore to a draw point system below. Development is carried out with three boom rubber tyred jumbos. All haulage from the mine is in 20 and 35 tonne rear dump trucks. All aspects of the mining operation are discussed including ventilation, pumping and drainage, services and future planning.

Jan 1, 1974

Buoyant levels of world economic growth and recovery in intensity of metals usage suggest that demand for minerals will remain relatively strong into the 1990's. Supply constraints, low stock to use ratios, financial and political factors imply lower elasticities of supply for minerals in the future. The outlook for minerals and metals prices from a pro-ducers viewpoint is, accordingly, promising.The recent recovery in world minerals prices, following strong growth in the world economy over the last few years, makes it appropriate to consider the structural forces at work in the formation of world demand and supply of minerals. This paper will review past trends and consider some of the main economic issues facing the mining industry in the 1990's.

Jan 1, 1990

A brief review of the problems in ventilating and cooling deep and hot Australian mines is presented. An overview is given on the development of the controlled partial recirculation concept. The main part of this paper describes the first majo

Jan 1, 1994

By D Matthews

With the increasing demand for quality-specific ores, coupled to the reality of even more complex minable iron ore reserves, there is a growing need for real-time online material analysis of plant feed and product. For a full system mass balance, the combination of conveyor weight scales, flow and density transmitters are required. This alone does not guarantee product grade. For optimal process control and material blending, real-time online elemental scans in combination with the mass weighting is becoming more than a ‘nice to have’. These elemental scans located at key positions, enable the mining and plant operators to make informed decisions timeously, therefore ensuring product outcomes and optimising operations where material grade and the control thereof are important. Typically, these units follow the mining and primary crushing circuit as well as on the product conveyors, low-grade conveyors and tailings lines. Deployed after the primary crushing circuit, an analyser acts twofold:1. guaranteeing mining production, and2. processing facility feed blends.The analysers on the product conveyors guarantee saleable product. The analysers on the low-grade conveyor and tailings line complete the elemental balance and identify the potential of the low-grade and tailings for future processing. The system losses (accumulation) are calculated to determine the amount of material ‘lost’ during the processing stage which does not report to any of the aforementioned and can be used as a measure of the efficiency of the plant. A further advantage of the real-time online analysis of material is that immediate intervention can be taken in the event that the product is not of saleable product grade requirements. In the Khumani Iron Ore mine, Northern Cape, South Africa, run-of-mine (ROM), product and control analysers were included. Run-of-mine and product stockpiles are certifi ed, low-grade material is not currently directly measured, but calculated from the internal control loops. Iron units are reconciled between product and feed material.

Jul 11, 2011

By Kristiansen J

A series of laboratory blasting and ball mill grinding tests have been done on four different types of hard and competent rocks. The results show that exposing these rock types to a higher level of explosive energy will enhance their grindability. True blasting optimisation should therefore look at the whole comminution process from solid rock to a marketable product.

Jan 1, 1995

By Beattie T. A

The ability of explosives to fragment rock has been assessed in small scale trials at the Granite Rock quarry, Baimsdale, Victoria. Three 65 mm diameter holes were fired simultaneously in a five metre bench, and the rock collected, screened and weighed. The mass of fines increased as the explosive strength increased in the series 30(10 ANFOPS

Jan 1, 1990

By Corbett GJ

Magmatic-related low sulphidation hydrothermal ore systems at plate margins exhibit distinct spatial and temporal zonations which can be used to aid mineral exploration and development. Low sulphidation systems at all crustal levels exhibit the same paragenetic sequence of events: early breccia formation, followed by quartz - secondary feldspar - sericite/illite veining, then mineralisation, and final argillic overprint. This sequence of events is interpreted to reflect the initial emplacement of melts at high crustal levels, and the progressive cooling of that melt and release of magmatic constituents into a circulating hydrothermal system.

Jan 1, 1995

By Brady KT, Pattenden G

A laboratory size solvent extraction apparatus has been constructed, which incorp- orates three stages of countercurrent extraction, followed by two stages of counter- current stripping. The model uses a gravity flow system from one stage to another and air lift pumps to recirculate organic and aqueous phases. A novel pump/mixer system is used to transfer solutions from the mixer compartments to the settler compartments. The model has proven valuable in the teaching of solvent extraction principles.

Jan 1, 1984

The Oregon-Idaho graben evolved after widespread Uwleiitic flood basalt volcanism associated with the arrival of the plume head of the Yellowstone hotspot beneath southeastern Oregon approximately 17-16 Ma. The north- to north- northeast-trending, 50 km-wide graben evolved between 15.5 and 10.5 Ma during east-west extension. The graben is part of a middle Miocene back-arc rift (1,100 km long) that includes the northern Nevada rift, the Baker and LaGrande grabens, and the Chief Joseph dike swarm of the Columbia River Basalt Group. The graben ceased to be a volcano- tectonic depression as the cross-cutting western Snake River plain began to evolve at approximately 10.5 Ma.

Jan 1, 1995

By K E. Mudzanani, T A. M Msagati, D T. Maiga, T T. Phadi, M R. Letsoal, B M. Chabalala, S W. Limani

This paper addresses critical environmental, health, regulatory and scientific concerns related to gold mining activities in the specific area of Barberton, Mpumalanga, South Africa. The paper thus calls for informed decisions to be made by the authorities to safeguard both the environment and people’s health. The novelty of this study is based on its comprehensive nature of the simultaneous assessment of both cyanide and potential toxic elements (PTEs) in tailings, while taking into account their composition variability over time. By combining these aspects, it is then possible to provide a holistic understanding of the contamination risks associated with mining tailings and thus justify the need for regular monitoring and supervision to ensure compliance against regulatory limits. Additionally, this paper considered investigating the dynamic nature of tailings, which are subject to changes in their chemical composition due to exposure to weathering by various agents. In this study, the determination of weak acid dissociable (WAD) and free cyanide in tailings was performed using a validated method employing the South African Council for Mineral Technology (MINTEK) Laboratory Cynoprobe. The PTEs in tailings were determined by an inductively coupled plasma optical emission spectrometer (ICP-OES). The results revealed that the tailings contained primarily substantial amounts of PTEs, including Fe (87 566 to 37 800 mg/L), Cu (271 to 110 mg/L), Mn (2100 to 680 mg/L), Ni (400 to 390 mg/L), Zn (180 to 68 mg/L), Cr (645 to 510 mg/L), As (450 to 128 mg/L), and Pb (up to 35 mg/L). The cyanide concentrations in tailings varied between 0.20 mg/L and 0.26 mg/L for free CN (with a mean of 0.23 mg/L in water leaching), 0.23 mg/L to 0.28 mg/L for free CN (with a mean of 0.25 mg/L in alkali leaching), 0.24 mg/L to 0.35 mg/L for WAD CN (with a mean of 0.28 mg/L in water leaching), and 0.31 mg/L to 0.39 mg/L for WAD CN (with a mean of 0.35 mg/L in alkali leaching). The measured concentration of cyanide and the PTEs was compared to the minimum permissible levels enforced by the South African Department of Water and Sanitation (DWS) and the Water Research Commission (WRC) regulations that govern the disposal of hazardous constituents into the environment. Additionally, it was observed that the concentrations of contaminants in the tailings exceeded the acceptable minimum limits for hazardous waste exposure, posing risks to the environment and human health.

Apr 16, 2024