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By R. S. Francis

There are no manuals or handbooks for budding mill superintendents or process plant managers. Most who obtain this level of responsibility have gained their training from watching the good and bad of their predecessors and the successful ones have themselves graduated from the school of hard knocks. This paper attempts to provide some helpful guidelines and direction for those who aspire to better manage a mineral processing facility. The authors have 20 years combined experience in senior management roles at nine different mineral processing operations in Australia and overseas, covering gold, base metals and mineral sands. This summary of tips and pitfalls will hopefully benefit future leaders in mineral processing and metallurgy.

Jan 1, 2007

By H. Warren Newcomen

The southwest wall of the Lornex Pit at the Highland Valley Copper mine has been experiencing slope displacements since 1978. Measures to manage the displacements on previous pushbacks have included stepping out, scheduling pushbacks to unload the crest of unstable areas, slope dewatering and mining with intensive slope monitoring. The final pushback on this wall is currently being mined and substantial modifications to the slope geometry could prove to be uneconomic. As a result, a campaign of surface water collection and diversion, horizontal drainhole drilling and deep well drilling is currently underway to maintain an acceptable degree of stability to the end of mine life. The various factors contributing to instability, including engineering geologic controls, rock mass strength, and surface and groundwater hydrology are presented. Movement trends, displacement magnitudes and stability analyses results are also discussed.

May 1, 2002

By C. S. Maggs, L. Shwydiuk, H. W. Newcomen

The southwest wall of the Lornex Pit at the Highland Valley Copper mine has been experiencing slope displacements since 1978. Measures to manage the displacements on previous pushbacks have included stepping out, scheduling pushbacks to unload the crest of unstable areas, slope dewatering and mining with intensive slope monitoring. The final pushback on this wall is currently being mined and substantial modifications to the slope geometry could prove to be uneconomical. As a result, a campaign of surface water collection and diversion, horizontal drainhole drilling and deep well drilling is currently underway to maintain an acceptable degree of stability to the end of mine life. The various factors contributing to instability, including engineering geologic controls, rock mass strength, and surface and groundwater hydrology are presented. Movement trends, displacement magnitudes and stability analyses results are also discussed.

Jan 1, 2003

By M. C. Baumann

The Getchell Mine is located in Humboldt County, Nevada, approximately 70 km northeast of Winnemucca. Slope management has been a critical factor in the feasibility of mining operations since they began in the early 1930's. Although underground entries began in 1937, underground production was limited because hanging walls consisting of clay gouge and crushed rock tended to collapse into the workings. Controlling these collapses required extensive timbering. Due to these poor ground conditions, surface open-pit mining was the primary mode of production from 1938 to 1967 with only minor contributions from underground operations. Mining was suspended in 1967 due to economic pressures. From 1960 to 1967, the previous operator mined the property in three open pits. Initially, these pits were constructed with footwall benches, but these failed. These failures were aggravated by construction of 60° slopes in footwalls with shale partings dipping into the pit at 43° to 60°, resulting in large planar failures and wedge failures. In response, the previous operator adopted a slope parallel to the bedding planes.

Jan 1, 1993

By L. K. Walker, G. A. Kosick, P. D. Young

"MillEX is an information management system designed by mineral processors for mineral processors. The system utilizes ""cutting edge"" software technology to gather and store all automatically and manually recorded data from the plant operation and laboratories. This data is delivered to the desk of superintendents, metallurgists, technicians and managers, and permits the user to query, correlate, graph, report and present this data in minutes. In the past this task would have taken days and even weeks of tedious work to complete.MillEX allows the engineer/analyst to quickly develop a very thorough understanding of the complex relationships of process variables and equipment that exist in the plant, and their effect on product quality and quantity. The time and resources that are currently wasted on duplicating data entry will be an effort of the past.This paper describes the structure of MillEX and how it conforms to the needs of mineral processing personnel.INTRODUCTIONPicture a personal computer on your desk which will carry out the following commands:1. Plot a graph over the last six months, using weekly averages, of percent minus 200 mesh material in the primary cyclone overflow.2. Overlay this graph with a graph of concentrate grade versus recovery over the same time period.3. Retrieve a prior month end report, update all operating supplies tables and metallurgical performance with this months data, and embed the graphs created above.4. Edit text and print the current month end report. This is only one example of the type of power MillEX isbringing to the mineral processing industry."

Jan 1, 1992

By S. Culp, P. Metcalfe

Web technologies and the Internet have revolutionized the computer industry. The Web browser technologies have also moved to portable devices such as Personal Digital Assistants (PDAs) and mobile phones. This paper looks at how to implement a Web Server solution and addresses some of the inherent advantages in the technology. It will also look at some examples of how plant productivity can be managed with a Web Server approach.

Jan 1, 2002

By R Dunne, S Hart, G Levay

While water represents a major proportion of the mineral pulp processed in flotation circuits, relatively little research effort has been committed to understanding and controlling the influence of water quality on this process. Historically, this probably stems from the perception of water as an inert transport medium. However, the changing attitude towards water as a valuable resource, has given impetus to increasing requirements to use relatively impure make-up water supplies such as treated effluents and a high proportion of internally recycled water. In turn, this has resulted in the need for a more detailed focus on process water quality and its control to minimise adverse effects on sulfide flotation. Along these lines, prior to commissioning of a new concentrator at their Cadia Hill Gold Mine, Newcrest Mining was proactive in examining potential water sources and the influence of water quality on flotation of their copper/gold bearing ore. An extensive water quality survey of all major potential water supplies to the concentrator was undertaken. The flotation performance of the Cadia ore in each of these waters was investigated on a laboratory scale. The results of these studies identified that water quality could indeed have a significant influence on the flotation process. Since operations at the Cadia Hill concentrator began, water quality surveys of both make-up water sources and recycled flotation circuit waters have been carried out on a regular basis. By doing this, a database of water quality has been established which can be compared with plant performance. In parallel with the water quality surveys, a series of laboratory flotation tests have been conducted using a standard ore and waters from various streams to monitor changes in flotation performance as a function of water quality. These tests have indicated that certain water types may have a significant influence on plant performance. More research is required to better understand the impact of water quality on sulfide flotation. This understanding will help operators to minimise adverse effects, while maintaining the best utilisation of available water resources.

Jan 1, 2003

By J. R. Donald

"Project development has been increasingly formalized in the past decade, with most organizations having extensive and descriptive deliverables documents and processes to govern the stage gate progress of capital projects. Although this has improved the general governance of capital project development and execution, it has perhaps not led to improved business success. This paper identifies specific challenges associated with developing complex projects with multiple stakeholder interests over the long timeframe of the project life cycle. The paper outlines these challenges and suggests management approaches and aspects of project development where increased focus is required to achieve improved business outcomes."

Jan 1, 2015

By C E. Woolley, A Hosseini, J Foster

Northern Star’s Thunderbox Open Pit C-Zone cutback was designed to maximise extraction in a short life excavation; In fresh rock on the western wall this included 20 m to 30 m bench heights with 6.5 m to 10 m berm widths and a 90° pre-split angle. Rock mass quality in this area is generally fair to good, however, there are sections where the dominant foliation runs parallel with the designed pit wall, and more closely spaced, altered, foliation is present: these areas are difficult to predict and prone to failure. Stringent controls and monitoring were required in order to safely access below these areas, in particular the use of slope stability monitoring radar, Trigger Action Response Plans (TARPs), re-entry procedures, visual inspections, drone inspections and day-to-day personnel awareness of the hazard. Robust and comprehensively planned remediation was also required after two significant slope failure events where long reach equipment and rope access techniques were utilised to remediate the areas in question safely, but also in a timely manner, such that expected production targets were impacted as little as reasonably practicable. This combination of rigorous risk management and well planned remediation resulted in a successful and complete extraction of the C-Zone cutback with no impact to operational safety.

Jun 22, 2022

By D. J. Wood

BHP Copper has grown, in just over six years, from a minor participant to the world's largest privately owned copper producer. BHP Copper's major asset is the world's largest copper mine -Escondida in Northern Chile. Ten years ago investing in Chile was considered high risk. Today, Escondida represents an investment of approximately US$2 billion. Reward is the result of managed risk and Escondida is a clear demonstration of both. The Ok Tedi copper and gold mine in Papua New Guinea represents a Rubicon of risk and a retrospective on reward in a developing country on the doorstep of a developed one. The story of these two mines encapsulates risk in the mining industry.

Jan 1, 1998

By Kristen R. Bingham

"Today, more than ever, drilling and blasting contractors are challenged to manage the ever-changing risks associated with blasting operations. New neighborhoods are encroaching upon mine sites and blasting projects are confronted with increasing scrutiny by permit issuing authorities and nearby residents disgruntled by new construction. The act of transporting explosives material to and from thejobsite is far from easy and trouble-free. At the same time, the pressure to stay in compliance with the growing number of government regulations continues to mount. While new tools and technology are appearing in the workplace to address some of these challenges, losses still occur. Can the datagenerated by this technology help drilling and blasting contractors make better decisions? While basic risk management principles are still applicable, do new tools and technology assist in the effort to prevent losses? What are the downsides? In this age of new technology, is face-to-face interaction still necessary? While technology is certainly a useful component in the drilling and blasting world, can it be helpful in defending claims?"

Jan 1, 2017

By F. Nelson

RJB Mining is the largest coal producer in the UK. In January 1995 the Company acquired the Central North and Central South Regions of British Coal consisting of: ? 15 operating collieries -including capital equipment ? 2 care and maintenance mines ? 16 operating Opencast sites ? Interest in 26 prospective and 46 potential Opencast sites ? Approximately 417 million tonnes of proven and probable reserves and considerable mineral resource ? 9 million tonnes of coal stocks ? Long term contracts to supply approximately 90 million tonnes of coal to National Power and PowerGen to the period of 3 March 1998 ?Approximately 7,600 employees and 4,500 mining contractual labour. Up to the acquisition RJB Mining had the capacity to produce 14 million tonnes of saleable output with an approximate 1,500 strong workforce.

Jan 1, 1998

An intensive safety campaign at Mount Isa Mines Limited from 1956 to 1966 saw the lost time accident frequency rate fall to half its original level. A review of the safety programme was carried out in 1967 and in 1968 the Five Point Safety System was introduced. The seven years since its introduction have been years of significant achievement both in production and safety. Improving safety is a fundamental part of Mount Isa Mines Limited's policy and this system has been a major tool in implementing that policy. To be successful personnel need to be prepared and trained for its introduction and subsequently counselled on its use. A carefully prepared programme is required to phase in various aspects of the system and to make use of complementary steps. The system has been a success and it is anticipated that the continued drive to improve the use of principles of the system will further improve safety. It is hoped that this paper will be of value to those personnel concerned with industrial safety in Australia.

Jan 1, 1975

By Rob Jameson

"The demand for commercial and residential construction has continued to evolve across the United States over the last decade. Our markets demand larger, deeper and inherently more complex structures, located within increasingly constrained urban locations and with challenging geotechnical conditions. As project demands incrementally escalate, specialty contractors are continuously challenged to extend their state of practice. Development in the size and capabilities of construction equipment, tooling, techniques, monitoring and verification systems over the last decade has consistently allowed contractors to build larger and deeper. For support of excavation (SOE), in addition to scale, selection of the most appropriate system has been a key to success in the most challenging ground conditions. This selection process is based on sound engineering and construction practice, and also prior experience, both positive and negative. Ultimately many Owners have chosen to manage their risk of SOE construction through design-build contracts, which allows specialty constructors to optimize the balance of cost, schedule, scope and associated risk based on their local expertise. Successful implementation of a design-build methodology begins long before a contractor is selected, with identification of key project requirements and risk factors during the feasibility studies and design development phases. In these early stages of the project development, advice and budgets are frequently solicited from Specialty Contractors. The Owner, Construction Manager and Consulting Team will filter this input from multiple sources to provide their specific recommendations, develop construction documents and select the appropriate form of contracting. Only in the final stages, after award of a Design-Build Subcontract, can the successful specialty contractor directly influence risk management approach on the project. A case study is presented from Block 9 in San Francisco’s Transbay District. This project demonstrates the incremental identification, assignment and mitigation of construction risk through the planning and design build process for SOE on the deepest planned excavation in San Francisco.INTRODUCTIONThe mature urban development market in United States results in high demand for complex Support of Excavation (SOE) schemes on constrained sites. The Design-Build approach can be applied to increasingly difficult SOE challenges, combining regional specialty subcontractor knowledge and experience in order to optimize solutions for cost and schedule. The most successful applications will involve early engagement of shoring subcontractors within the project teams, during feasibility and design development stages, in order to identify key scope and risk issues, and their potential solutions. Throughout the project development, it is important to reasonably assign responsibility for construction risks amongst the project stakeholders who are best able to control them.This paper presents a case history for San Francisco’s Block 9, a well-planned and successfully executed design-build SOE project in San Francisco’s Transbay Redevelopment area. Throughout the 4 year period from the Developers initial proposal to the Redevelopment agency, through completion of excavation down to subgrade, the project team developed a series of increasingly refined SOE schemes, with corresponding scope definition and cost and schedule estimates. This program relied on early identification of key challenges and risks for the project, and evolved through multiple phases of proposals as first the General Contractor (GC) and then Specialty Shoring Subcontractor were engaged for the project. The scheme, cost and schedule refinements continued throughout construction in order to accommodate unanticipated conditions and events as they unfolded."

Jan 1, 2017

By J Li, J Regan, D Payne

The Caval Ridge Mine is an open cut coalmine and located within the Bowen Basin region in Central Queensland, and commenced mining and processing operations in 2014. A number of geotechnical challenges for managing dragline bench and lowwall stabilities have been encountered in both southern and northern pits over the years. Southern Pits contain steep seam dips of up to 15° (27 per cent) whilst the northern pits also have shears below pit floors. Geotechnical guidelines to manage the risk of dragline bench failure and lowwall instability have been developed and improved since these geotechnical challenges were identified. The dragline guidelines include dragline tub offset distances from the 60° Line (SDL) or buttressing thickness for different seam dips greater than or equal to 8°. The low wall stabilisation guideline established floor disruption widths and depths depending on seam dips and presence of floor shears to known depths of up to 3 m. As mining operations advance, lowwalls have remained stable until floor disruptions were fired, then returned to stable soon after the shot. The maximum distance of lowwall cracking with blasting has been as far back as the second spoil peak (the prestrip truck dumps construction limit). These failures need to be eliminated to allow the operational flexibility and haulage benefit of constructing the prestrip truck dumps behind the first spoil peak, while maintaining no risk to personnel or equipment. The floor shear depth was verified by collaborating with the exploration teams and taking advantage of the already planned 8-inch coal quality core holes, drilling them an extra 5–10 m past the coal seam floor and locating the shear presence. With this continuous improvement effort, no lowwall failures have occurred during floor disruption firing from the second strip after the new floor disruption depth guidance have been applied. This paper documents the processes for developing these geotechnical guidelines, operational implementation, and outcomes. Operational applications over the years confirmed that these guidelines have effectively managed the dragline bench and lowwall failure risks related with the steep seam dips and floor shears in this open cut coalmine.

Nov 29, 2022

The Callie Underground Gold Mine (Callie) is owned by Newmont Asia Pacific and located 531 km north-west of Alice Springs in the Northern Territory. Historically, stopes have been mined utilising a primary and secondary stoping sequence with cemented aggregate fill and rock fill respectively. Current and near-future mining will employ long hole open stoping with rib pillars and rock fill with a paste fill system approved to allow a higher extraction ratio from mid-2011. The Callie rock mass is of good quality with little or no mining difficulties during development and stoping to a depth of 1140 m below surface. Development is currently occurring at depth of 1360 m below surface. Stress damage previously observed only in secondary stope accesses is now observed in development unaffected by stoping stresses. A change in rock mass properties is being experienced with depth, with more pronounced and frequent joint planes. Also, other structures are intersected more commonly, such as lithological boundaries and fault zones. The 'Callie rock factory' mentality that has persisted for years is challenged. This paper covers an appraisal of the stress and ground condition changes at Callie. The appraisal outlines the mine design criterion that was developed and examines the transition from a low stress environment to one where stress damage is observed. Discussion includes a judgement on the rock mass damage observed in development, the dominant geotechnical factors influencing the change in ground conditions, and if a correlation can be made between the observed rock mass damage with stress through the use of numerical modelling.

Nov 25, 2010

By K A. Bunker, A D. Campbell, E Ah Mu, A R. Penney

The Ernest Henry mine is a transverse sublevel cave (SLC), which is relatively unique due to the 45 degree inclination of the orebody. To economically recover ore, each sublevel is horizontally offset from the previous level by around 25 m, depending on the orebody geometry. Mine development, slotting and initial production within this zone occurs in a high stress abutment that increases in magnitude at depth. These areas are seismically active and close to the hanging wall where cave propagation is yet to initiate. High stress conditions and the close proximity to the cave seismogenic zone results in challenging geotechnical conditions in the step out zone of each level and requires management of hazards including stress driven rockfalls, rock bursts and pillar failure.This paper outlines how these hazards were forecast using numerical modelling and geotechnical monitoring. Risk management techniques included dynamic ground support design, development of a new mine layout and extraction sequence as well as delayed re-entry into seismically active areas. Ongoing monitoring, instrumentation measurements and field observations were used to track the effectiveness of the controls.Future production levels are forecast to experience increasing stress and seismicity, which will increase demand on excavations and installed ground support. Ensuring the techniques and controls for monitoring, measuring and mitigating stress and seismic hazards are enforced is essential for continued safe production.CITATION:Campbell, A D, Bunker, K A, Ah Mu, E and Penney, A R, 2016. Managing stress and seismicity in an inclined sublevel cave, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 319–328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Rusdian F. Kayadoe, Michael B. Hutahaean, Sandi A. Firmanulhaq

Deep Mill Level Zone (DMLZ) mine is located in Papua, Indonesia operated by PT Freeport Indonesia (PTFI) with approximately 1,500m below surface. The ore body extend 1230m width from northwest to southeast by 300–400m length east-west. The mine currently produces at full production of 80,000 tons per day until 2041. Part of the extension of current active production block and mitigation sits 225 m above the production block 1 (PB1) and 2 (PB2A and PB2B) which located in 2590L, named production block#4 (PB4W and PB4E). As the mining continues at PB1N, PB2A, and PB2B, the cave growth vertically and laterally to south perimeter of the footprint affecting the integrity of PB4W/E footprint. Currently, PB1N and PB2N are in active production whilst PB4E development continues from South against PB1N cave, as can be seen in Figure 1. A slight overlapping between PB1E and PB4E intentionally to promote cave connections between the two caves. Despite low stress model in the PB4E near existing caves, the PB4E cave propagation expected by the large strain and will be propagating in tension failure to the PB1E cave. Hence, designing the drill drives edge and first drawbell location as close as possible to the PB1E cave is necessary to guarantee cave connection. Since PB4 footprint development commenced in December 2021, there have been a substantial cave propagation observed from existing downhole monitoring. As the PB4 footprint designed perpendicular to existing DMLZ PB1 cave, adjustment of the development edge design is necessary to reflect the progression the loosening zone propagation to the South. Final life of mine design for extraction, undercut and ventilation level were decided in October 2023 considering latest update cave (fractured/ yielded) boundary. Numerical model of potential rock mass damage also aids the decision to locate the drift edge design. Predicting the cave progression impact is critical to both production at the existing active blocks and development of the new area. The use of cave shape data from year 2021–2023 gives an insight of the cave shape estimation at the end of 2024 when the undercut drift will be developed. This paper presents actual cave growth of active production blocks and its relative vertical progression impact as the result of drawing in order to plan for acceptable rate and provide mitigation once the minimum acceptable rock mass condition and minimum pillar threshold achieved.

Feb 1, 2025

By Elizabeth Gardiner

Tailings and water management facilities are integral components of mine and mill operations. They must be managed for the long term to ensure that safe and environmentally responsible stewardship is achieved. The Mining Association of Canada (MAC) has developed and published two manuals to provide guidance to mining companies on sound practices for the safe and environmentally responsible management of tailings facilities: ???A Guide to the Management of Tailings Facilities; and ???Developing an Operation, Maintenance and Surveillance Manual for Tailings and Water Management Facilities. The Guides were designed to help companies develop and implement tailings management systems that include environmental and safety criteria, to improve the consistency of application of sound engineering and management principles to tailings and water management facilities through their full life cycle, and to demonstrate this to regulators and the public.

May 1, 2003

By R. D. Williams

"In a very real sense, Butte, MT is where the copper came from that won two world wars. The price for that unrestricted mining and smelting of copper came due in 1983 when Butte was declared a Superfund site.One of the most complex remnants of this mining history is the Parrot Tailings site. The Parrot smelter operated from 1881 to 1910, moving Upper Silver Bow Creek to the south and depositing approximately 283,000 m3 (370,000 cu yd) of waste material adjacent to Upper Silver Bow Creek. Additional mixed waste from other processing sites deposited below the Parrot tailings at the Northside Tailings, Diggings East and Blacktail Creek Berm total approximately 171,000 m3 (224,000 cu yd) of contaminated material. As part of the Superfund remedy, the U.S. Environmental Protection Agency (EPA) proposed leaving all these wastes in place. This proposal prompted a detailed criticism by several geoscientists familiar with the site. The EPA’s 2006 Record of Decision (ROD) did in fact leave these wastes in place, which set the stage for a series of studies that continue to refine how best to protect extensive completed Superfund Remediation downstream of Upper Silver Bow Creek. History of the Parrott Mine and tailingsPlacer gold was discovered in Silver Bow Creek, the headwaters of the Clark Fork River only a few miles from the Continental Divide in 1864. This discovery led to a stampede of placer and lode claims. One of the first lode claims located was the Parrot lode, located in the fall of 1864. Progress for developing a mine at the Parrott was slow, and it was not until 1876 that one of the original locators encountered a rich vein of chalcocite. Butte had its first copper mine.The Parrott Mine was patented in 1879 and by 1881 the Parrot, having lost a “t”, concentrator and smelter were built. The smelter and concentrator were an immediate success with a considerable market for processing the district’s rich copper ore. In 1885, the employees of the Parrot smelter bought the Butte Reduction Works, another smelter. In 1885, dams were built on Silver Bow Creek to contain various tailings and related processing byproducts (Fig. 1).By 1890, the various smelters in Butte rendered Butte’s air quality as suffocating (Fig. 2). An 1889 funeral procession was rumored to have gotten lost in the thick smelter smoke and somehow ended up at the Centennial Brewery. A city ordinance was passed late in 1890 in an attempt to control smoke. The Parrot smelter employed approximately 500 men by 1890. Through the 1890s, the tailings produced grew from approximately 91 t/d (100 stpd) to more than 181 t/d (200 stpd). Copper values in the tailings were initially as high as 4 percent, but as the processing improved that was reduced to 1.5 percent."

Apr 1, 2019