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By R. R. Guzman

In this study, the "Mine Project Risk Management" methodology, MPRM (Botin et al. 2011), has been applied to characterize the sources of uncertainty and to quantify risk in the mining engineering stages of Block Caving mining method. As the result, rock mass caveability and ore fragmentation were identified as the two most relevant parameters of this process and a methodological model has been developed to quantify the risk associated to each of these two parameters. Furthermore, the applicability of the proposed model has been validated using as a case study the Chuquicamata Underground Mine Project in Chile.

Feb 23, 2014

By S Davidge, J Pile, R Schumann, E Kepe, W Stewart, M Ridd, B Rathi

Geographical constraints, including steep terrain and high rainfall, at the Ok Tedi copper-gold mine in PNG’s Western Province present Ok Tedi Mining Limited (OTML) with significant challenges in mine waste management. Waste management includes discharge of tailings into the local river system and storage of waste rock from the mine pit in waste rock dumps which erode into the river system. Copper bearing skarn mineralisation is associated with a massive sulfide (mainly pyrite) deposit. Consequently, waste rock and tailings can contain significant amounts of pyrite. Without appropriate management, these waste streams represent a risk of producing acid and metalliferous drainage (AMD) when discharged to the river system. Throughout the life of the project, OTML have developed evolving strategies to manage mine wastes and mitigate AMD.

Aug 2, 2023

INTRODUCTION The mineral sample is the fundamental unit upon which the mineral appraisal is built. Values derived from the sample are the most important quantitative measurements made in the total evaluation process. The sample value

Jan 1, 1980

This paper describes operational experience with seam gas and spontaneous combustion management, gained during ten years of production history (1993 to 2003) in the Wynn seam at Dartbrook Coal mine. In addition, comparisons are made with more recent operational experience in the overlying Kayuga seam. Development and retreat longwall operations were undertaken in a 4.0 m thick working section of the Wynn seam, contained within the lower quarter of a circa 24 m thick mega seam, from 1993 until mining operations were relocated to the overlying Kayuga seam in 2004. Production from the first block of the Kayuga seam is currently underway with seam gas and spontaneous combustion management requirements being refined as further operational experience is gained. Seam gas management techniques, including pre-drainage with pressurised fracturing, surface to underground goaf drainage of a carbon dioxide rich seam gas and novel, high capacity ventilation circuits, were employed in the Wynn seam. Ventilation strategies included operating up to carbon dioxide STEL concentrations of 3.0 per cent in segregated return airways rather than being limited to the TWA-TLV concentration of 1.25 per cent. The spontaneous combustion experience at Dartbrook Coal has, to some degree, resulted in a change in the way the risk is managed in Australian coal mines. Values of carbon monoxide make and hydrogen concentrations are profoundly different from previously recommended management plan trigger levels and those used elsewhere in the industry. However, the detection of higher hydrocarbons together with rising oxygen depletion ratios and absolute hydrogen concentrations remain as indicators of advancing spontaneous combustion events. In this respect, experience gained in the Wynn seam was important in the initial management of the shallower Kayuga seam, an essentially greenfield site with no prior operational experience being available.

Jan 1, 2005

By P. N. Erasmus

This paper considers the fundamental concepts of support design for underground openings in highly stressed ground. It concludes that the conventional deformed reinforcing bar, woven mesh and cable lacing support methods that have been widely used in deep gold mines are quite in appropriate for the support of highly stressed tunnels. The following is suggested as the criterion for adequate dynamic support under rockburst conditions: the energy absorbed by a support unit (yielding through some acceptable limited displacement) should exceed the kinetic energy generated by the mass of rock that is intended to be retained by that unit. Duraset in conjunction with SRK Consulting has developed a yieldable steel tendon called the Durabar®. It is unique in the sense that it cleverly utilizes the property of the ductility of ordinary low-carbon steel from which it is made to accommodate the excessive displacement it is subjected to in the case of rockbursts or swelling ground.

Jan 1, 2009

By A R. Penney

Since mining-induced seismicity first became apparent at the Beaconsfield Gold Mine in 2002, there has been an ongoing program of geotechnical investigations to understand the phenomenon and allow for the development of strategies to manage the risks it posed to personnel, the business and the community at large. Studies resulting from a seismically induced rockfall on Anzac Day 2006 have been extensive, and have advanced the understanding and management of seismicity at the mine. Enhancement of the mineÆs seismic array, implementation of extensive monitoring of ground behaviour, improved ground support and reinforcement design, and ongoing numerical modelling provide a technical framework for the management of seismicity. In addition, extensive involvement of the workforce in risk assessment and the development of standard work procedures (SWPs), has contributed to a æbest practiceÆ approach to manage seismic hazards at the mine.

Jan 1, 2008

By M. D. Strachan

Technical & Procurement Services Limited (TECHPRO) in Ashford, Kent, UK, have been appointed as Project Managers for the major rehabilitation of the Copper Smelting complex of Nkana Division, Zambia Consolidated Copper Mines Limited, (ZCCM) Zambia. In outline, the overall scope covers three main areas: a) Transfer and implementation of new technology into Zambia for the production of primary copper. b) Replacement of gas collection and gas treatment circuits to guarantee high quality feed to the acid plants. c) Completion of a number of minor projects in the copper smelter and associated utility plants to complement changes in the primary smelting technique. This paper describes the Project Management methodology and style used by TECHPRO to tackle typical problems that arise in retrofit projects of this type. Reference is made specific aspects of the smelter projects to illustrate solutions to the problems. The subjects. addressed highlight the complexities not only of having a -Client 5,000 miles from the Project Office, but also the difficulty of co-ordinating and controlling the performance of min sub-contractors who are also geographically distant.

Jan 1, 1991

By William E. Stanley

The paper examines the problems that arise in undertaking socio-economic impact studies to meet the requirements of environmental-impact legislation governing new mine development or expansion. An approach to undertaking socioeconomic impact studies is outlined, responses to specific problems are discussed and ways in which the mining company can use these studies to meet its general objectives are explored. The paper concludes by examining how a socio-economic study, as required by legislation, can be used to assist the mining company in achieving some general objectives it will have in developing a mine.

Jan 1, 1979

By P. Turcotte, E. Karampinos

"Construction of underground excavations in squeezing ground conditions faces several technical challenges that can result in delays in production and high costs due to rehabilitation. A review of the behaviour of drifts under squeezing ground conditions was undertaken at the LaRonde mine. In particular it focused on implemented strategies to control the observed large deformations. The mine experiences a large range of squeezing ground conditions, mostly driven by the presence of foliation and high stresses. This results in large deformations over one meter in radius. A comprehensive ground control strategy has been implemented with the aim to manage, rather than arresting drift closure. The evolution and effectiveness of the employed support strategy are discussed based on documented field observations. In complement to the field implementation numerical models are used to provide further insight on the observed squeezing conditions.INTRODUCTIONThe development of underground excavations under squeezing ground conditions is usually associated with excessive rehabilitation and significant failure of ground support due to large deformations. Cost research case studies have concentrated on squeezing ground conditions in tunnelling. An overview of the methods used for the identification and quantification of squeezing and the numerical methods for the simulation of these conditions in tunnelling has been provided by Barla (2002). Numerous support systems that can manage ground deformation are available for civil engineering tunnelling. Nevertheless, the use of these systems in mining would result in high support cost and production delays. Mining operations have higher development rates and shorter service life. This study focuses on the behaviour of underground excavations under squeezing ground conditions in hard rock mining.In a mining context, the magnitude of deformation is usually higher than in civil engineering tunnelling as there is a higher tolerance for operation purposes. Potvin and Hadjigeorgiou (2008) noted that in mining, squeezing is encountered when the total displacement of an excavation reaches at least tens of centimeters over the life expectancy of a supported drive and is associated with considerable damage to the ground support."

Jan 1, 2015

By Glen Mc Gavigan

The roof of the Sishen cave is being mined in order to exploit 6.8Mt of high grade ore. The cavity is filled with quartzite backfill in order to support the roof in the event of collapse. The cave dips at approximately 37o, is 260m along dip and 70m along strike and has a total volume of 261,391m3. GPS and optical monitoring techniques were attempted to detect subsidence but proved to be impractical. The GroundProbe Slope Stability Radar (SSR) uses differential interferometry to measure sub millimetre movement in a rock face. The SSR was applied in a non production situation and detected subsidences of 38mm/day before visual signs of instability were detected. The rate of deformation detected was slowing as a result of the roof coming to rest on underlying backfill. Monitoring during production drilling detected a sudden subsidence of 18.6mm/hour which resulted in the evacuation of personnel from the area. Further inspection of data showed that the rate of deformation was slowing and production was allowed to continue without further incident. The SSR has helped dispel the fears of workers and has proven that subsidence can be accurately measured and delineated with the SSR.

Jan 1, 2006

By Leggate J

In the past many coal mining projects commenced without any consideration being given to eventual site rehabilitation. Now that site rehabilitation is assuming greater importance with changing community expectations, and standards are becoming less negotiable, it cannot be ignored in either the development of mine working plans or economic models. The "unspecified" rehabilitation measures associated with many existing projects will be the subject of debate for some time to come yet. It would be wise to plan for the future. Once an agreeed standard of rehabilitation is accepted, good management involves considering practices which will facilitate eventual rehabilitation at least cost. Without planning for rehabilitation, many mines have adopted practices which are likely to result in very expensive rehabilitation measures and impact significantly on the overall profitability of the ventures. With adequate planning, procedures can be developed which achieve the same short term goals without significantly effecting cash flow but with very significant impacts on the final rehabilitation cost. This paper looks at the disposal of tailings and overburden in the coal mining process. The industry has in the past had an obvious preference for the "perceived" cheaper procedures for waste management such as wet disposal of tailings and high dumping of overburden. There are alternatives. The paper discusses the principles which should be incorporated into tailings and overburden disposal systems and identifies viable alternatives.

Jan 1, 1991

By R. Bruce Ferguson

"The Kettle River Operation of Echo Bay Minerals Company is located about thirty kilometers north of the town of Republic in northeastern Washington State. In tum, Republic is about a hundred and seventy kilometers north and a little west of the city of Spokane, Washington. It is also about fifty kilometers south of the town of Grand Forks, BC, Canada. At this time it is the only gold mining and milling operation in the State.Tailings are stored in a double lined, zero discharge facility. It became evident in mid 1996 that the rate of free water accumulation in the tailings pond was going to result in the level in the pond reaching its permitted freeboard elevation long before the solids plus pore water capacity was reached.We then embarked on a mission to manage tailings pond water on several fronts: reduce fresh water usage in the process, divert spring seeps and surface runoff and install a system to enhance evaporation.IntroductionThe Republic area is an historic gold mining district. Hecla operated its Republic unit from 1892 until closure in 1994. The Kettle River Operation processing plant is located in the San Poi! river valley at an elevation of just under a thousand meters. The facility consists of a ninety thousand ton ore storage pad as the mines are remote and truck haulage is subject to interruption due to weather and road restrictions, jaw and cone crushing with screening, rod and ball milling to an eighty percent passing size of seventy five microns. This is followed by preaeration with high purity oxygen supplied by a vacuum pressure swing adsorption plant plus lead nitrate addition to achieve passivation of the sulfide mineralization such as chalcopyrite, pyrite and pyrrhotite. Conventional cyanide leaching and carbon in pulp adsorption completes the loop. Tailings are treated with air/S02 to achieve cyanide destruction. Plant capacity is 1,815 tons per day. Our license requires that there be no detectable free cyanide in the tailings pond water and a maximum of forty parts per million weak acid dissociable cyanide. The operation started in 1989 with production from the Overlook Mine located about five kilometers further up the same valley at an elevation of twelve hundred meters, hence the location of the mill. Current mine production comes from Lamefoot in the Curlew Lake valley, about ten kilometers distant, and K2 in the Kettle River valley about fifty kilometers away. Both are at an elevation of about 800 meters. Lamefoot produces 1,360 tons per day and K2, 455. Both are underground operations."

Jan 1, 1998

By R Fury, I Skepper, D White, G Miller

Although the Pressure Acid Leaching (PAL) of nickel laterites has been conducted at Moa Bay, Cuba, since the early 1960s, the commissioning delays generally encountered by the æsecond generationÆ of PAL lateritic nickel producers in the late 1990s have demonstrated the potential complexity of the PAL process and the importance of technical risk management in maximising the realised project value. This paper describes some of the strategies used by the Ravensthorpe Nickel Project (RNP) to manage the technical aspects of the Ravensthorpe project risk. Central to these strategies is the use of Front End Loading (FEL) to deal with issues early in the development phase, when changes to the project structure can be made most effectively and cheaply. Such an approach requires a management philosophy that recognises risk as a potential cost, which accepts responsibility for dealing with risk, and which is prepared to provide adequate resources for risk management.

Jan 1, 2004

By T. H. Phillips

The Mission Mine is an open-pit copper mine located 18 miles south of Tucson, Arizona in the eastern foothills of the Sierrita Mountains. Mining is done on 40 foot benches using P & H 2100 shovels and 170-ton Terex trucks. Drilling is accomplished With two (2) Bucyrus-Erie 45R?s, one (1) Bucyrus-Erie 60R and two (2) Ingersoll Rand T-5?s. For secondary drilling. a Joy VCR-ISO truck mounted drill is used. The mine is currently operating 3 shifts/day, 7 days/week at 59,100 tons per day, with the mill receiving 28,500 tons per day. The management of the drilling and blasting program requires extensive record keeping in all phases of the operation. This is essential in order to evaluate different products and procedures.

Jan 1, 1988

By Vladimir I. Klishin

Complex method of ruling of rock pressure is considered in conditions of rapid roof subsidence. The purpose of this method is elaboration of emergency devices into hydraulic props. Also method of unloading of solid roofs is worked out. An analysis of means of protecting hydraulic props of powered supports 6om dynamic loads made it possible to divide them into four classes according to principle of operation: emergency, operating hm an increase of pressure; emergency damping; emergency, operating according to the "plastic element" principle; inertial emergency, operating hm dynarmc loads. It was established that the overwhelming 'majority of designs of the first three classes of emergency devices (EDs) are based on !mditional approaches, which exhausted their possibiiities of high-speed response. Delay on their opening is caused mainly by inertia of the moving locking parts. In our opinion, the most prospective are EDs using the inertia of the moving locking parts for depressurizing the piston cavity of the hydraulic prop with a minimum delay (inertial EDs). The essence of the designs of EDs having an inertial principle of action is that into the hydraulic prop containing movable and immovable elements is additionally introduced a spring-operated contracting support, which is installed on the movable element. Under dynamic loading of such a hydraulic prop hm the roof, the support moves relative to the movable element, performing the role of an inertial mass, which leads to instantaneous depresswization of the piston cavity of the hydraulic prop. Technological measures for unloading of solid roofs consists in creating of long oriented cracks in rock massif. Description of method for creating cracks, demanding equipment and means for cone01 the progress of splits are included. Also technological schemes for realization of the method of saving underground mines and rock mass are included. The results of experimental realization of this method on the Kuzbass and Poland coal mines are also included.

Jan 1, 1997

By P J. Scales, D Boger

Technological advancements in mineral processing have increased the feasibility of refining low-grade ores. Because of this progression and continual depletion of high-grade ore deposits, much larger volumes of waste material are produced. At the same time, increasing environmental legislation and cost competitiveness dictate that these wastes be disposed of in a manner that is both environmentally acceptable and economically viable. To achieve these criteria, many mineral processing industries are dewatering waste streams in order to reduce the volume of tailings and increase water and reagent recovery. The subsequent dry disposal of these highly concentrated mineral tailings requires a thorough understanding of the effects of dewatering on the flow characteristics. Dry disposal represents a paradigm shift in engineering. The tailings are engineered to suit the disposal requirements, as opposed to engineering a facility to accommodate the tailings. It is therefore important to understand how the material properties and operational parameters can be modified to produce the desired tailings flow and deposition characteristics. As concentrated suspensions usually exhibit non-Newtonian behaviour, determination of the disposal plant operating conditions requires a thorough understanding of the rheological characteristics of the material. The implementation and optimisation of dry disposal methods involves three concurrent and interdependent rheological studies to determine:the concentration required to achieve the optimum spreading and drying characteristics of the tailings once deposited; the optimum conditions for pipeline transport; and the feasibility of dewatering the slurry to the required concentration. The paper presents an overview of the issues pertinent to management of the flow properties and processing of dewatered waste streams.

Jan 1, 2002

By R. Armstrong

Due to limited available level ground, Nkomati Nickel Mine cut a weathered rock slope at the base of a mountain spur in order to create a platform for construction of the primary crusher plant and run-of-mine stockpiles. As space is limited around the mining area, ore processing at Nkomati is based on a high reliability of flow of material through the crusher plant, with minimal usage of other and larger designed stockpiles. Evidently, any crusher plant shutdown will render the mine as a whole unproductive and put excessive strain on the medium- to long-term large ore stockpiles, the deposition rates for which are restricted by founding material consolidation requirements. At the onset of the 2012 rainy season, movement was identified on the slope monitoring system and cracks developed on the slope. After a minor failure on the crusher slope an assessment of the slope stability was conducted and a slope management plan recommended, which included deployment of real-time monitoring. An evaluation of the conditions leading to instability was conducted and the likely causes for the failure identified. A full evaluation of the slope monitoring, rainfall, and mining conditions was undertaken and movement triggers were determined. This paper describes the events leading to the development of the failure and the evaluation of the monitoring data to determine a management plan for the failure that allowed for minimal shutdowns of the primary crusher.

Jan 1, 2014

Coal mining in the Bulli seam in the Southern Coalfield in New South Wales has experienced the dangers of outbursts of coal and gas. These incidents present a major risk to the safety of mine workers and consequently a threat to the overall viability of the mining operations. Since the occurrence of a major outburst incident in the South Bulli Colliery in 1991 involving three fatalities, the primary contributory factors associated with coal/gas outbursts in the Bulli coal seam have been identified and a strategy for the management of the outburst risk has been formulated by the cooperation of mine operators, mine workers and the Department of Mineral Resources. Utilisation of risk management techniques in combination with modern gas drainage technologies and geological control methods have led to the formation of this effective outburst management plan. Clause 15 of the Coal Mines (Underground) Regulation 1999 in NSW has made it mandatory in an area of outburst to carry out mining in accordance with a code or guidelines developed for mining in outburst prone areas (DMR, 1999). In this paper an outburst management system is discussed which was developed for collieries in the Southern Coalfield that brings together all the available information including past experiences and risk management techniques in a documented form in order to maximise safety of mine workers. It is concluded that since the introduction of the outburst risk management systems in the Southern Coalfield in 1994 considerable reduction in outburst incidences have been experienced.

Jan 1, 2003

By Paulo Roberto, S. M. Roberto, Francisco Valadares Póvoa, Evandro C. Silva

The market of mineral goods worldwide is characterized by a growing pressure on suppliers for better quality products, lower prices and productive processes which are energetically efficient and environmentally friendly. These pressures force the mineral industry to re-think not only the present models of exploitation of natural resources and production, but also their own model of techno- logical development. This paper outlines the model and the experience of Technology Strategic Planning (TSP) adopted by CVRD to face these demands, warranting and expanding its participation in the current markets and developing new businesses.

Jan 1, 1998

By Francesco Chiappalone, Miriam Piemontese, Lance Waddel, Paolo Perazzelli, Emidio Tamburri, Roberto Schuerch

The Three Rivers Protection & Overflow Reduction Tunnel is part of the Long-Term Control Plan of the City of Fort Wayne, Indiana (USA). The 4.9 m internal diameter tunnel, of length approximately 7.5 km, is excavated at a depth of approximately 40–60 m through carbonate rocks using a slurry TBM. Due to the high hydraulic conductivity of the rock mass and the high in-situ ground water pressure (up to 6.5 bar), the management of the water inflow during the TBM advance and standstills, represents the major challenge for the project. This paper outlines the geotechnical conditions and the hazards related to the large water inflows expected in the pre-excavation phase and discusses the experience gained during the construction of the first 8,224 feet (2,507 m), (first third of the total length of the tunnel).

Jun 13, 2021