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By B Besa, E K. Chanda

It has long been recognised that narrow vein mining needs innovative approaches to mine access and mining methods in order to improve the economics of this vital part of the mining industry. The mining equipment used currently requires large openings in narrow vein-type deposits making mining operations uneconomical. In view of this and other shortcomings of the current mining practices, a study was initiated to investigate the potential of using low profile electric loader with mounted conveyor in conjunction with the electric monorail haulage system (EMTS) to load and haul the blasted material, particularly in decline development and main haulages. Computer simulation based on the General Purpose Simulation System/Henrikson (GPSS/H) is used to model the system and evaluate its performance. The results are compared with those for conventional mining using trucks and loaders. The EMTS provides competitive haulage rates in substantially smaller excavations than is currently achievable. According to simulation results, the electric loader in conjunction with the EMTS had the same number of blasts as the conventional system and hence the same advance rate of 3.33 m per 12 hour shift. Furthermore, the total drill-blast-load-haul cycle time was less than the conventional system by one hour.CITATION:Besa, B and Chanda, E K, 2012. Evaluation of low profile electric loader in conjunction with electric monorail haulage system in narrow vein mining, in Proceedings Narrow Vein Mining 2012 , pp 221-228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

One of the problems with mining projects is the setting of the design criteria that will best match the requirements. Normally this is expressed in economic terms but can be other factors. With massive orebodies these problems are often compounded by the general lack of distinct mining boundaries. A technique using evaluation surfaces was developed at Palabora for the underground mine design. This technique has subsequently been applied on several other mining projects to assist in the determination of the design criteria. This paper discusses the method, illustrated by some of the results of these studies.

Jan 1, 2000

Attempt has been made to determine the nature of charge on activated carbon surface by studying the electro-kinetic properties of the carbon in the presence of cations, anions and aurocyanide solutions. The zeta-potential measurements were made in the presence of individual ions and also in combinations. The cations and anions chosen were those commonly associated with gold bearing ores in Kalgoorlie area. It was found that the iso-electric point of Norit Carbon was at pH 4.45; below this pH the charge was positive, while above, it was negative. In the absence of gold cyanide solutions and in the presence of individual cations the i.e.p. shifted to the alkaline range (pH 7.2-8.5) while in the presence of anions the i.e.p. was shifted to less than pH 3.5. In the presence of aurocyanide solutions, the iso-electric point was still in the acid region irrespective of whether anions or cations were present. The probable mechanism for such a behaviour has been attempted after measuring the specific conductivities of solutions before and after gold adsorption, by studies using the electron- probe-mirco-analyser, and S.E.M. on the carbon surface.

Jan 1, 1982

Quite often the reserve assessor becomes enamored with the numbers gen- erated and forgets the basis for his assessment. The quality of the assess- ment can only be as good as the quality of the input data. The use of seismic data from the Gippsland Basin in assess- ing Esso/BHP's oil and gas reserves is an excellent example of this principle. By significantly improving the quality of seismic data, a much more reliable estimate of a field's reserve potential can be made. In addition, it provides the basis for further delineation drill- ing which, as recent experience in Gippsland has shown, often leads to increased reserves.

Jan 1, 1979

By Omnes G

Sixty Schlumberger electrical soundings were carried out in the Depot Springs area, near Agnew, Western Australia as part of an investigation into the availability of groundwater for the Agnew nickel project. The object of the survey was to locate calcrete aquifers related to Tertiary drainage channels on the Pre- Cambrian surface. The electrical soundings were initially interpreted using sets of master curves and auxiliary point methods. Electrical sections were produced and contour maps prepared of apparent resistivity for AB=80m, total conductance of the overburden and transverse resistance.

Jan 1, 1975

The equity market is now very much within a global village environ- ment, with various exchanges acting as agencies for the big casino. In this predicament, mining companies, who provide the most extensive, but relevant risk assessment information, will be best placed for favoured treatment by potential international investors: But what risk assessment information in summary form can be provided to support a resource/reserve statement? Even more importantly, does "objective" data exist, whose trends will support a resource/reserve state- ment? A prime need of the informed mining investor is to determine whether or not the resource/reserve statement is believable? But more importantly will it be realised? While the implications within the text of the majority of reports on resource/reserves suggests that the estimates are conservative, the record indicates that very few estimates are. In fact, to date, reports claiming to be conservative in respect of the overall grade estimate at a specfic cutoff have not reflected the realised grade at the stated cutoff; it has been more common for the realised grade to be lower than implied by the resource/reserve statement. Further, it is not uncommon for penalty elements to be understated and these components are rarely incorporated within resource/reserve statements.

Jan 1, 1988

The underground mining of a narrow vein hard rock orebody is a capital and labour intensive method of extraction. Due to the nature of underground mining it is difficult for higher level managers to physically see the efficiencies and inefficiencies of a particular method. Extraction methods and sequencing often need to be altered from the original planned methods as a result of mine developent, providing more in depth information as it progresses. As a result of these issues contract mining of these orebodies is common practice. There are several types of contract structures for the purpose of underground contract mining with many complex permutations of them that reflect the different needs of each individual company and orebody. The different contracts are arranged dependent on the mining companyÆs desire to transfer or, alternatively, embrace risk. This presentation gives a brief overview on these different methods and their various advantages and limitations with regard to small scale and narrow vein underground mining. With respect to these different contracting methods, the presenter reviews the mutual growth benefits of emerging partnering opportunities, specifically with regard to smaller explorers exploring and developing prospective mining tenements. The specific advantages to small explorers include the resource flexibility and speed of project development that private mining contractors can provide. Given the contracting methods that are available, there is potential for small private mining companies to gain minor stakes in major projects and major stakes in medium sized projects by employing innovative contracting solutions to provide mutual benefits to the parties. Some potential scenarios to this effect are suggested in the presentation. This paper is available as a PowerPoint presentation only.

Jan 1, 2006

By F Soleimani

Coal and gas outburst is a common hazard in coalmines and due to the complexity of its nature, efficaciously predicting the possibility of its occurrence is intricate. The mechanical and gas flow properties of coal, in situ and mining-induced stresses and geological structure are involved in outburst occurrence, whereas suggested thresholds for its prediction do not consider them all. Numerical modelling is known as an effective method that can not only consider couple the effect of different physics but also analyse the effect of associated parameters. In this paper, a coupled fluid flow and geomechanics model has been developed in COMSOL Multiphysics to simulate outbursts by considering the effect of gas pressure and composition, damage mechanics on related coal properties, and progressive excavation and mining-induced stress. For the proposed fully coupled outburst model, the effect of pore pressure and sorption are applied to the stress while the influence of stress changes and damage are considered in updating coal porosity and permeability in each time step. In addition, to study the effect of mining-induced stress, the excavation process is simulated by changing the material properties over time according to the schedule of heading development. Then, outburst initiation is analysed from the energy point of view by using the concept of energy conservation law. The simulation results are used in calculating energy sources of the outburst initiation, also, the effect of particle size and ejection velocity are studied, and the significance of particle size effect on the energy analysis and deformed coal on outburst initiation is discussed.

Oct 12, 2022

By Walton M. C

A combination of flotation and smelting technologies is proposed as a cost-effective means to maximise the revenue of base metal operations. The proposed treatment route breaks the grade - recovery nexus associated with the treatment of ores exhibiting difficult mineralogy in conventional plants. Aspects of the two technologies are reviewed and typical capital and operating costs presented. A significant improvement in revenue is demonstrated in a worked example, where a copper-lead-zinc operation is examined in terms of the conventional and proposed treatment options. For the selected ore, the net smelter return per tonne of mill feed improved 57 per cent, from US$89.70 to US$141.10 with the proposed treatment option. This represents an additional US$51.4 million in annual revenue. Metallurgical operating costs increased by US$20.12 per tonne of mill feed for an incremental capital requirement of US$30.3 million for an existing operation.

Jan 1, 1992

By Koh P. T L, Varnas S. R

Fluid flow, heat transfer and combustion in a nickel flash smelter have been investigated by numerical modelling and flow visualisation. The three-dimensional numerical model incorporates turbulent two-phase fluid dynamics, radiative heat transfer and combustion. The main features include the use of the k-E turbulence model, the Lagrangian tracking of particles, radiative heat transfer based on the spherical harmonics method, and chemical reactions. The predicted flow fields are in good agreement with data obtained from a series of flow visualisation experiments on a cold water model. The interaction mechanism between the fluid flow and the solid particles is examined for a range of particle sizes both with and without injected oil in a series of simulations. The heat transfer in the shaft is dominated by combustion and radiation, whereas the ignition of particles is influenced by the particle size and the added oil. Flow and temperature fields for both gas and solid particles are presented as well as the fraction of sulphur removed from the particles.

Jan 1, 1992

By D Obeng, D Alexander

Over the past five years, commodity prices have been high and the focus of many plants has been æthe more metal the better, at whatever costÆ. In the recent economic crisis, the focus has shifted more to reducing the cost of production and operating at higher efficiency. Since 2002, JKTech has partnered with the Century mine in north-west Queensland to transfer technology and understanding through the good, bad and ugly economic environments, using methodology and techniques arising from research at the Julius Kruttschnitt Mineral Research Centre (JKMRC) and other research institutions around the world as part of the AMIRA International P9 Project. The JKTech studies were concentrated around the primary zinc circuit. During this period, Century expanded the primary zinc regrind capacity, installed additional scavenging capacity, installed and commissioned a Jameson cell for concentrate cleaning in the carbon preflotation circuit, and installed additional primary grinding capacity. Flotation circuit models were developed for each of the survey campaigns and enabled opportunities for further improvement to be identified, implemented and tested in the subsequent campaign.

Jan 1, 2009

By P Card

“Let’s get discipline and quality into easy to understand evaluations!” Project Managers and MetPlant Operators accept poor quality evaluations because they are generally unaware of what they should expect.The 2010 draft AusIMM ‘Guidelines for Techno-Economic Evaluations’ were collated by a subcommittee of practitioners and are regarded as best practice.They apply directly to projects and metallurgical plant evaluations, including those with a heavy technical basis. They can be applied to technical problem solving where there are no monetary computations. Project Managers and MetPlant Operators should demand that economic models and evaluations follow the six principles. They should become working tools which are easy to understand, fit for purpose, consistent, rigorous, record sources of input data, have key graphs and are rapid to audit.

Aug 8, 2011

In the hard rocks of the Nordic countries of Norway, Sweden and Finland underground works have a long tradition. Today the subsurface has been taken into use for a wide variety of purposes. In this paper only the more uncon- ventional examples are described such as caverns for drinking water, sand bunkers, molasses silos, wine and liquor stores, cold stores, heat storage, waste disposal and state archives. The particular use of unlined high pressure tunnels and socalled air-cushions for hydropower schemes is discussed. The dual use of subsurface air-raid shelters for sports activities seems to be a special Nordic tradition. Some cost figures are given and the advantages of using the underground is Discussed.

Jan 1, 1987

By Ho D, Yang J

The ready availability of powerful desktop workstations, which combine 3D real-time graphics and processing speed better than that of supercomputers of a few years ago, now allows the cost-effective solution of real world geomechanics and underground mining strength simulations. The inclusion of geotechnical factors such as rock joints and porous flow on strength and stability are discussed together with the range of available deformation and failure models for soil, rock and concrete. This paper describes the capabilities provided by finite element graphics and analysis software for modelling and sequential investigation of both excavation and lining, or rock bolting, construction sequences. Examples of the use of finite element models in mining are also included in the paper, together with a discussion of the required people, software and computer hardware resources required to achieve timely and productive results.

Jan 1, 1995

By D Feng, G C. Lukey, J S. J, R R. Dagastine

An ongoing challenge in the coal industry is pyrite removal using the flotation method for fine particles. The use of a æseparation in frothÆ (SIF) technique to recover coarse particles of up to a few millimetres in size has presented a potential solution. However the commercial success of SIF is still limited due to the poor understanding of the separation mechanism. The particle floatability in SIF is determined by the constructive or destructive stresses resulting from the forces exerted by the particle on the bubble films. Hence, the surfactant properties and the mineral characteristics (eg hydrophobicity, shape, etc) are the key factors that control the interaction between the particle and froth. In the present work, the interaction forces between different particles (ie crushed glass, pyrite and coal) and a single air bubble are measured in a non-ionic surfactant solution (pentaethylene glycol mono n-dodecyl ether, C12E5) using an atomic force microscope (AFM). Experimental results show that the interaction is primarily dependent on the contact angle (ie the degree of hydrophobicity of the minerals). For crushed glass, the transition from repulsion to attraction was observed as the contact angle increased. As the concentration of C12E5 increased, the adhesion force was suppressed due to wrapping effect. For coal and pyrite with much higher hydrophobicity, long-range attraction was observed. The effect of shape factor was only visible at high surfactant coverage where sign of destabilisation became noticeable on the retracting force curve. These results provide a fundamental understanding of the direct interaction forces of a complex real system between an irregular particle of either crushed glass, pyrite or coal and a single air bubble. Theories developed for interpretation and modelling are thus far based upon the study of ideal systems of glass or polystyrene spheres and an air bubble and were incapable of explaining the interactions in complex real systems. The presented measurements were a first approach to the problem of real mineral-bubble interaction in flotation systems. Thus, the results can only best be interpreted semi-quantitatively.

Jan 1, 2005

Although developed primarily for sintering tantalum, the unit to be described can be used to heat-treat metals in the form ofa bar, wire or strip, by passing a current through them. The upper temperature limit with this type of heating is the melting point of the metal being heated.The unit was designed for vacuum work, but. various gases can be used if required.Briefly, the vacuum sintering furnace consists of a bell which is counter-balanced and may be lowered onto the brass base plate which holds the electrodes. A rubber ring seal is used for vacuum work. The lower flexible grips are bolted to the brass base plate which is at earth 'potential, while the other electrode passes through the plate by way of an electrically insulated vacuum seal. This upper electrode, the height of which can be altered as desired, the lower grips, and the bell are water cooled. The vacuum line to the pumps and a line to the vacuum gauges also lead from the base plate. The more important sections of the unit are described below.THE BELLThe unit was designed so that the bell could be lifted clear of the base plate and the electrodes, thus facilitating adjustment of the latter and the mounting of the specimen to be heated. A double walled steel bell, 20 in. high, with t in. cavity was used. The bell was fabricated from 10 gauge mild steel sheet using a double overlapping run of arc welding for all seams. A water inlet and outlet...

Jan 1, 1946

The influence of strongly chemisorbed solutes such as oxygen and sulphur on the rates of reactions at the gas-liquid iron interface is briefly reviewed. Deductions from recent studies of the rates of decarbur- ization of carbon-saturated liquid iron indicate ideal adsorption behaviour for sulphur over a wide temperature and composition range. This is in fair accord with available infor- mation on surface tensions in the Fe-C-S system. Previously unpublished results for the kinetics of the 14C02-CO exchange reaction are in accord with ideal absorption of oxygen on liquid iron. The derived value for the ideal adsorption coefficient of oxygen at 1550¦C is in quantitative agreement with measurements of the depression of surface tension in the Fe-0 system. Consideration is given to the applicability of such results to the violently agitated systems of steelmaking.

Jan 1, 1980

By Jones IO

Although small units have been in use formany years, particularly in opal mining at shallow depths, there has been little effort in the past to explore the potential of the vacuum lift system in other more demanding applications. Recent developments in Western Australia by a small number of mining companies, contractors and manufacturers have seen the design and construction of several larger, more powerful units for use in winzing, shaft sinking, hoisting and spillage removal. Some of these units have proved very successful and suggest that they could be developed for a wider range of applications and duties in future.

Jan 1, 1984

By Gilbert DJ, Lemon NM

A case history of a two year study of low grade ores in the Middleback Range area with the objective of defining possible areas of interest from a combination of geological- petrological-metallurgical criteria. Covering the general geology of the area and ore types; the results of metallurgical testwork and the pattern of evolution of these tests; the petrological explanation of the results of the testwork; the culmination of the work in the selection of areas of best potential for more intensive work. Jaspilites consisting of magnetite, hematite and limonite with quartz and silicate-carbonate-sulphide minerals are hosts to high grade iron mineralisation but also constitute a large low grade iron Reserve.

Jan 1, 1975

By Renwick MT

Two innovative ground reinforcement products have been developed for use in the mining industry. One of these products is a high strength polyethylene (HOPE) bar for use as a rib bolt in underground coal mining and as a corrosion proof tendon in open pit mines. The other product is a cable bolt (Ultrastrand) which demonstrates enhanced load transfer and is available in continuous lengths. Ultrastrand's exceptional in- situ performance and versatility makes it ideal for mechanised installation in both underground and surface mining operations. Details of these products are presented and results from labortaory and field trials are discussed.

Jan 1, 1992