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The Metallurgical Development of an Enargite-Bearing Deposit

Sep 13, 2010

By R Hoeppel, D Harimon, A Fisher

This paper examines the importance of examining the relationship between biology and geochemistry when designing a biopile to treat alkaline soils impacted by petroleum hydrocarbons. At a site in Nevada a large, unlined pit was constructed in a loamy sand soil and filled at regular intervals with a mixture of jet fuel, lubricating oils and waste solvents which were set on fire by the local fire department for training purposes. During its period of operation numerous chemicals were also dumped into the pit for disposal purposes, including dichlorobenzene and various chloroethylenes. As a result of these activities a large groundwater contaminant plume was formed. As a part of the site remediation process a decision was made to perform a limited source removal and excavate the top three to four metres of contaminated soil from the burn pit and place it in an engineered biopile. The location of the training pit is in a heavily mineralised basin where the background sulphate level in groundwater exceeds 5000 ppm. Due to naturally occurring biodegradation of the petroleum hydrocarbons a large portion of the sulphate was converted to sulphide which deposited in the soils as marcasite in the anaerobic soils. The initial attempt at soil remediation was to use a forced air treatment scheme that had worked well in small scale laboratory testing. Unfortunately, when attempted in the field on a large scale, marcasite reacted with atmospheric oxygen resulting in internal biopile temperatures exceeding 90¦C resulting in the virtual sterilisation of the soils without remediation occurring. In order to solve this vexing problem Pintail Systems, Inc developed an anaerobic culture that allowed the pile to be operated under anaerobic conditions. Within three months the biopile successfully demonstrated on a large scale significant biodegradation of the refractory petroleum hydrocarbons.

Jan 1, 2004

There is growing acknowledgement that successful organisations, including mining companies, achieve their competitive advantage by better managing their employees, customers and other stakeholders. The fact that I have been asked to address this conference is perhaps evidence of the recognition of the importance of ensuring the improved management capabilities of the personnel within Australian mining companies. As many of you will be aware, prior to my appointment to the role of President of Minera Alumbrera Limited (MAA), the operator of the Bajo de la Alumbrera project, my career had been more generally focussed on industrial relations and human resources management. My appointment was met by surprise in some quarters, as it is unusual for a person without the technical background of a mining discipline to manage a world-class mining operation. However, it was recognised early in the life of the Alumbrera project that the operation did not lack technical expertise or a committed workforce; rather what was required was innovative management of the project and its operational resources, particularly given that we were operating with totally ægreenÆ workforce in a country without a large-scale mining culture. It is my experience that a particular shortcoming of mining companies is that they have tended to ægrowÆ managers based on their technical expertise rather than people management skills. Historically, many companies have assumed, or at least hoped, that their better technical people would develop the requisite skills to take on the challenges of management. Such philosophy has not always met with success. Whilst the topic for my presentation was originally published as People in the Mining Industry, within the context of the overall theme for this plenary session, People: Education for the Future, it is a subject with an extraordinary breadth of possibilities for discussion. Therefore, I have chosen to redefine my presentation to People Management Issues in Offshore Mining Projects,an issue which I consider to be an important area within the overall topic and one which has particular currency given the increased tendency by Australian miners towards offshore exploration. It is also relevant from the perspective of continued rationalisation of our industry, the recognition that there will be more large-scale, global corporate mining entities and that significantly more mining professionals will become æcitizens of the worldÆ. We therefore need to prepare our future leaders for these challenges. The topic also allows me to highlight the importance of an holistic management approach as the establishment of a new project in a foreign environment puts into stark relief the need for the application of the full range of competencies, rather than the narrow ætechnicalÆ approach to doing business. I hasten to add, however, that the mining industry is not alone in this regard and I was interested to read an article in the Weekend Australian of 22/23 January 2000, which reported on the first key speech of former Westpac CEO, Bob Joss, as Dean of the Stanford University Graduate School of Business. He said: à We know that when our students go out into the world, if they have to struggle, it will not be because theyÆre not smart enough, or they donÆt have enough good ideas. It will be because they struggle over managing themselves and their relationships to other people. The article then went on to say that Bob Joss foreshadowed an initiative to build alliances between the Business School and other Humanities departments within Stanford University to draw on their learning. Other business schools have also recognised this need, albeit somewhat late in the day, as have the most enlightened of modern corporations; in summary, successful businesses have recognised that in an age where competitive advantage through, for example, technological breakthroughs is very short-lived, it is the quality of management that will provide the leading edge. By using the Alumbrera project as a case study, I will identify certain of the challenges with which companies and individuals may be confronted in the establishment of a greenfields project outside Australia. However, many of the issues raised will have direct application in the context of the development of an Australian operation. My objective is to provide an indication of areas which should be considered at the formative stages of a projectÆs development, with particular focus on the issues of people management. I would expect that such a study would be of benefit to companies, education institutions and individuals in preparing themselves for similar experiences.

Jan 1, 2000

By Ö Aydan

Rock dynamics is one of the most important topics in the field of rock mechanics and rock engineering. The spectrum of rock dynamics is very wide and it includes the failure of rocks, rock masses and rock engineering structures such as rock bursting, spalling, popping, collapse, toppling, sliding, blasting, non-destructive testing, geophysical explorations, science and engineering of rocks, earthquakes, and impacts. Undoubtedly, the rock dynamics issues in Mars would remain to be the same. Although mankind has no direct access to Mars yet, the Mars exploration rovers (Opportunity, Sprit, Curiosity and Perseverance), Mars Reconnaissance Orbiter and InSight Lander provided very valuable data so that some rock dynamics issues can be recognised. The author reports his considerations on rock dynamics issues in Mars from very careful examination of images and data provided from MERs and MRO and discusses their implications.

Nov 29, 2022

By J F. Costa, A Grigorieff

Coal mining reclamation is a worldwide concern. This paper presents a Brazilian example where the economic aspects of reclamation are considered. The basic goal of the study is to transform the reclamation procedures into an economic process by integrating the use of land after reclamation and developing profitable post operations. Some of the activities considered in this case study include: using of the coal pit as a landfill, considering appropriate landfill design and construction; using the area for forest development; and developing grassland, forests of native species and the construction of ponds for fishery. This study will conclude that the mined area is: capable of storing large quantities of waste at a competitive cost and at a low environmental risk; commercial forest development is economically feasible; and the lakes and other reclaimed areas can be integrated into the landscape creating a fresh water supply and an area to raise cattle.

Jan 1, 2005

By P Brown, M Nagarajan, A Green, P Dare-Bryan

Coal loss is an important issue at many coalmines, with losses of five per cent being common. The type of loss varies from mine to mine but is dependent on mine strata, the drilling and blasting processes applied and the mining method used. Typical coal loss mechanisms from the drill and blast process are coal roof damage and edge loss. Usually a reduction in coal loss is in direct competition with the need to provide material that is well-fragmented and a muck pile that has the required cast percentage. These competing issues were addressed over a two-year period at a mine in the New South Wales Coalfields by implementing a five-step approach. This was centred around building an understanding of the coal loss mechanisms utilising proprietary heave- modelling software, measuring coal losses by comparing survey to drill and/or gamma logs and implementing appropriate coal loss reduction processes. The end result exceeded expectations with a 95 per cent reduction in coal loss. Mine excavation productivity was maintained and coal loss minimised to less than one per cent of the in situ coal block.CITATION:Nagarajan, M, Green, A, Brown, P and Dare-Bryan, P, 2015. Managing coal loss using blast models and field measurement, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 429–436 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

The polymerisation of silica is found to interfere with thickening of leach pulps at Risdon. Hydroxyl ion and fluoride ion are catalysts for this reaction. Stability may be obtained by the presence of aluminium or ferric iron.INTRODUCTIONAt Risdon it has been a matter for satisfaction that, although the concentration, of silica in leach solutions is appreciable, it has ,given relatively little cause for anxiety.However the margin of safety is small and some intermittent difficulty in thickening leach residues during the last few years has prompted a further investigation, certain parts of which are described here since they may be of general interest.Leaching and ClassificationThe method of leaching which is practised at Risdon has been described in, two previous articles, by W. C. Snow (1936) and S. W. Ross (1949) to whiCh the reader is referred for detail. Continuous leaching is practised, the circuit solution flowing through five air agitated pachucas in series, to tlie first of which calcine is added. The circuit solution, which also enters the first pachuca, consists of spent electrolyte from, the electrolytic cells and contains 90 -gm. of free sulphuric acid per litre. About 80 per cent of the solublezinc oxide is extracted from the calcine in the first pachuca, at a pH value of 1-1 (7 gm.H2S04/1 at 55 to 60°C. In the later pachucas the leaching rate decreases sharply. The leach pulp which leaves the 'last pachuca contains an average of 17 gm. of free acid per litre, corresponding to a pH of 1.7; but, owing to variations in extraction, the end point fluctuates between 2.5 and 0·3 gm. free acid per litre (pH:> 1·5 to 2.5). The average flow through the plant is 1,250,000 gallons per day, which corresponds to a production of 300...

Jan 1, 1958

By H Kim, J Park, J Lee

Silico-ferrite of calcium and aluminium (SFCA) is a bonding phase in the iron ore sinter. The phase transition upon melting of SFCA was investigated with Differential Scanning Calorimetry and Confocal Laser Scanning Microscope. The initial melting of SFCA occurred at 1183.2°C and a massive melting was found at around 1351.1–1358.2°C. A phase transition-melting was investigated at 1476.5–1478.7°C. The liquid phase was composed of immiscible phases. The present results would be utilised to design a new iron ore sinter for better processing performance in a hydrogenenriched ironmaking process.

Jun 19, 2024

By M Gabbitus, B Young, T Lukins, M Slater

This paper details the implementation of a new type of grade control system at the Black Star open cut mine in Mount Isa, Queensland. It explores the site requirements for grade control, what as previously in place and what the site required moving forward. It also details some of the features of the system installed and why it was chosen over other grade control systems available. Black Star open cut mine has been in operation since late 2004, and was developed to extract the surface extents of the Ag-Pb-Zn mineralisation previously mined in the Isa Lead Mine. Black Star is currently mining seven distinct orebodies in and around active void hazard zones and hence, its grade control requirements are very detailed and complex. The implementation of a new system to manage the model update and block out processes was, therefore, of critical importance to the site and required a detailed understanding of the requirements of the entire mining team from drilling through to geology, survey and production. Having previously run the grade control process using site specific æblack boxÆ scripts and macros, Black Star needed to implement a more open, auditable and flexible system, which allowed the geologists to control the process and make strategic changes as the situation demanded. MineSightÆs Axis Grade Control, with its flexible, generic framework for managing the process, met these demands. Being an out of the box solution that requires minimal setup and training was also a key factor in the decision to use it.CITATION:Lukins, T, Slater, M, Gabbitus, M and Young, B, 2012. The introduction of axis at Black Star Open Cut, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 71-74 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By S Vink, A Wolhuter

Increasingly the community and government regulators are calling for æzero dischargeÆ mines. Some mining companies are beginning to explore ways in which they can transition to zero discharge. When striving to attain zero discharge, mines must consider multiple variables in addition to water quantity. These include climate regime, water quality and regional water budgets. This paper explores the drivers behind the concept of zero discharge mines and will use examples to illustrate the feasibility of attaining this goal.CITATION:Wolhuter, A and Vink, S, 2013. Is zero discharge a viable or useful concept in mine water management?, in Proceedings Water in Mining 2013 , pp 329-334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

The seams of black coal occurring in Victoria are so disturbed by faulting, wash-outs, thinning, etc., that it is necessary, for the prevention of costly errors in development, that close boring be undertaken so that the correct positions of the shafts, tunnels, main and auxiliary roadways can be set out in order that the area can be economically worked. The State Coal Mine has two boring plants continuously at work, which have given good service for the last twenty-five years.The information supplied herein is merely our experience in boring at the State Coal Mine over an extended period. The type of plant in use is that known as the Victoria Drilling Plant, equipped with an 11 h.p. portable oil engine, using power kerosene as fuel. It was purchased in 1914, complete with mechanism for cable drilling, capable of boring to a depth of 1500 ft. with a guarantee of 1000 ft., with Calyx cutters, boring rods and all necessary equipment for the sum of £1473. The chief mechanical features of the plant are as follows:-The derrick is in the shape of a tripod (see Fig. 1), two of the legs being of steel channel built together to form a frame which, when lowered on to two sets of road wheels, forms a carriage for the transport of a portion of the boring equipment. The third leg is made of oregon in the form of a double bow, with bolts and distance pieces between the wooden sides. The top of this is hinged on to the steel frame, and the bottom is fitted into a cast iron block, having two small wheels to facilitate erection. A rope attached to the cast iron block and to the winch easily...

Jan 1, 1936

The past decade has seen a great increase in activity in deep seismic reflection profiling of the continental crust. Some 20 countries have conducted field experiments and the total length of deep seismic profiles surveyed to date is approximately 25,000 km. This total is very large compared to the quantity of such data that existed previously, but very small compared to the total length of seis- mic profiles of the shallow crust carried out for petroleum exploration, which some- times has exceeded 600,000 km on land in one year alone and 1,600,000 km/yr on land and sea. Furthermore, 25,000 km of seismic pro- filing corresponds to exploration of only a tiny fraction of the total volume of the entire continental crust. Thus at this stage of development of the subject, one must be wary of generalizations that are based on these limited data and then ex- tended in scope to include the crust everywhere. The state of the subject is such that virtually every new seismic line reveals totally unexpected seismic fea- tures, a sign that the subject is in its major discovery phase and a warning to the generalizers. Nevertheless, in addition to much new information on deep crustal structure in specific locations, some broad consequences of application of this powerful geophysical technique to a region of the earth not pre- viously explored in this manner are be- coming clear. One is that, as seismic data on the deep continental crust become more abundant and more revealing of complexi- ties, the deep crust can be far better re- lated to rocks at the surface. Conse- quently, the geological style of reason- ing is now being extended from its normal domain of the near-surface to include the deepest crust in a comprehensive story of the evolution of the continents. This change is a subtle but important one and is evident, for example, in some cross sec- tions of the North American Transect Pro- gram, which show surface geology extended in a consistent, though speculative, manner to the top of the mantle. In other words,

Jan 1, 1987

By M Wen, J Gerit, C A. Pelletier, D Muggli

On-land waste rock dumps at BHP Billiton Base MetalsÆ Island Copper Mine (ICM) near the northern end of Vancouver Island, B.C. continue to discharge ARD. These waters, which amount to approximately five million cubic metres each year, are injected into a three-layer, meromictic pit lake for treatment. The top layer is brackish water, replenished by each yearÆs rainfall (amounting to nearly 2 m/year). This top layer of water must meet effluent permit limits for heavy metals. This water eventually exfiltrates through a æbeachÆ waste rock dump, which is 93 per cent submerged along the north shore of Rupert Inlet. The middle and bottom layers of the Pit Lake are saline and currently oxic (2 mg/L dissolved oxygen) and anoxic (0.03 mg/L dissolved oxygen), respectively. Spreading of a liquid fertilizer every ten days throughout the top layer results in plankton and bacterial blooms that scavenge zinc, copper and cadmium out of this layer eventually to become mineral sediment in the bottom of the pit lake. Adsorption on planktonic skeletons and mineral precipitates also scavenges these dissolved metals from the middle and bottom layers to form bottom sediment. Sulfate reduction has recently begun in the bottom sediments. Diagenetic processes in the bottom sediments will eventually transform most of the dissolved heavy metals into insoluble sulfides. Cycling of ferric iron between the sediment and the water column and back seems to contribute dramatically to the biogeochemical metal removal processes. This biogeochemical system serves to maintain the top-layer water well within permit limits for discharge to the environment.

Jan 1, 2003

By P J Savory

Ranger is a uranium mining operation located within one of the most environmentally sensitive regions of Australia. Geology has played an important role in mine planning, operations and rehabilitation since discovery of the deposits 25 years ago. The Ranger orebodies have a reserve total of 166 300 tonnes of U308 including 90 400 tonnes of U308 at North Ranger. At current milling rates these reserves give a mine life greater than 40 years. The uranium is hosted in Lower Proterozoic rocks of the Cahill I ormation and is associated with strong chlorite alteration. In pit grade control involves the use of calibrated probes and a radiometric truck discriminator allowing fast, accurate grade determination of material. Ore is defined at a cut-off grade of 0.2 per cent U308. Mineralised material is defined by the Uranium Mining (Environmental Control) Act 1979 (UMEC Act) at a grade of 0.02 per cent U30s. Natural water levels in the #1 Pit area vary as much as 7.5 metres between wet and dry seasons. Ground water inflow into the pit during the dry season is 600 m3/day. No significant slope failures have occurred in the pit. The environmental impact of mining operations is constantly monitored. Rehabilitation of non-mineralised stockpiles is ongoing. This paper discusses the interaction between geology, hydrogeology, rock mechanics and grade control with the present mining operation.

Jan 1, 1994

By K Seddon

Segregation of tailings on deposition can occur as a result of a) sub-aqueous deposition, and b) sub-aerial deposition at lower solids concentrations (i.e. when the solids concentration is less than the segregation threshold). The effects are likely to be more pronounced in the case of subaqueous deposition.This paper presents the results of an investigation of a sub-aqueous tailings facility.Data from the investigation show extreme variations in particle size and density compared to test results for non-segregated ‘all-in” tailings. The results indicate that on segregation both the fine and coarse splits tend towards a well sorted (poorly graded) mix, and both have significantly lower consolidated density than the all in tailings. This result is reasonably well known for the case of the segregated fines (“slimes ponds”) but less appreciated for the coarse fraction. The results suggest that if the effects of segregation are not allowed for, the overall density of the deposit can be seriously over-estimated at the design stage. Also the quantity of water retained in the tailings can significantly influence water recovery and water balance results.CITATION:Seddon, K, 2018. Segregating tailings – effects on density and water retention, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 299–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By N Pirouznia, F Rashidi Nejad, S Naraghi

Sungun Copper Mine, which is the second largest copper mining operation in Iran has a large tailings storage facility with a seepage control dam located downstream of the main dam. Surface and groundwater in surrounding area of the tailings storage facility has been monitored for ten years. This paper will discuss the results of the surface and groundwater monitoring and seepage control at the Sungun Copper Mine. The results of the study show that if the tailings storage facility influence the water quality of the rivers, this effect is not significant, so that the prevailing parameters of the measured parameters were within the permissible standard of drinking water in Iran.CITATION:Rashidi Nejad, F, Naraghi, S and Pirouznia, N, 2018. Surface and groundwater monitoring and seepage control at the Sungun Copper Mine, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 439–453 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By A D. Campbell

The sublevel caving (SLC) mining method is becoming more widely adopted as an underground mining method as mines become deeper and target lower grade mineralisation. SLC has been successfully adopted in increasingly complex and wide-ranging conditions in the past 10–20 years, demonstrating the flexibility of the method. Various challenges encountered at SLC mines around the world have led to significant differences in operating practices, mine performance and mine productivity. Unfortunately, aspects related to productivity, operational performance and best practice are not widely published and remain with individual companies. Limited information is publicly available to compare operational performance of SLC mines in the various conditions where the mining method is now being applied. To overcome this shortcoming, a global review of SLC operations was undertaken over a three-year period as part of the Cave Mining 2040 research consortium. The purpose of the review was to document technical and operational practices, hazard management strategies and key benchmarking metrics at SLC mines around the world. A total of 21 mines spread over four continents and 17 different mining companies were included in the project. The main outcome of the project was a manual of operational and technical practices, benchmarking of key metrics and documentation of the current state-of-the-art for each aspect of SLC mining. This paper describes the main findings from the benchmark in terms of mine productivity, including mine development, production and mining costs. The implications of mine scale, depth and ground conditions on operational performance at each of the benchmarked mines is described and charts are provided comparing key productivity metrics.

Mar 29, 2023

By R Morrison, P Walters, B Adair, V Jokovic

‘Grade Engineering<sub>®</sub> is an integrated approach to coarse rejection that matches a suite of separation technologies to ore specific characteristics and compares the net value of rejecting low value components in current feed streams to existing mine plans as part of a system-view’ (Walters, 2017). Two of these technologies are directly recoverable through screening stages: Natural Deportment and Induced Deportment. The potential for taking advantage of “Natural Deportment” by size following blasting and crushing has been demonstrated for a range of ore types. Simple and low cost screening can in some cases generate a fine product with improved grade and a lower grade oversize which can be directed to leach or to waste. Where an ore body consists of many different ore types, the traditional approach of blending to metal grade will often add to complexity of treatment, which will reduce the effect of “natural deportment” by size.CITATION: Jokovic, V, Walters, P, Adair, B and Morrison, R, 2018. Applying enhanced grade engineering to complex ore bodies, in Proceedings Complex Orebodies Conference 2018, pp 21–23 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

For the past five years the University of Queenslandhas, through its various workshops, been preaching to Australia that there was a potentially hazardous situation from earthquakes for urban Australia. A few people outside The University accepted this, but largely the warnings fell on deaf ears.The 1989 Newcastle earthquake changed that per-ception. The most important lessons to emerge from Newcastle were (i)the realization that in continental areas small earthquakes cause widespread damage:(ii)the local geology of an area is of great importance in the damage done by an earthquake.These two factors clearly indicate that, in the future, we must take far greater account of the "Urban Geology" of an area. This paper discusses the need for urban geology and its impact on seismic risk and compares that with the traditional methods of assessing seismic risk.

Jan 1, 1990

By P Fuller, A R. Penney

Re-commencement of mining in the Western Zone of Beaconsfield Gold Mine following a seismically-induced rockfall fatality in April 2006 required a change of mining method involving drilling and blasting from specially developed drives in the footwall of the orebody. Broken ore is mucked remotely from ore drives on each level. Support in the footwall drives is required to maintain stability during their development and as stopes are retreated, which increases induced stresses and further seismic events are triggered. The paper outlines the challenges involved and methods used to select the footwall drive support to handle both static and dynamic load demand. The importance of load development in the support system, its displacement capacity, the compatibility of support elements and energy absorption capacity of the support system are highlighted. It is usual in any support selection process to ensure that capacity exceeds demand to create a factor of safety. In this case the demands on the system relate to load, displacement and energy absorption and the support system capacity for each must ensure that appropriate factors of safety for each are achieved. The paper shows how these factors are not independent and that selecting a high factor of safety for load can lead to compatibility problems with support elements in the support system.

Jan 1, 2008