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By Jim Truskoski, Alain Bouchard, Andy Kerr, Germain Labonté, Jim Barrett

"Improving mill grade recovery relationships is always good business. INCO’s Clarabelle Mill has just undergone a $16 million process upgrade that was designed to improve nickel recovery by 2%. The “Mill Redesign Project” was completed on time, under budget and delivered the promised improvement in recoveries.This paper describes the methodology of the Mill Redesign Team, details of the process improvements and the critical success factors that helped the team deliver on its promises.With a payback of under one year, the Mill Redesign Project will play a key role in ensuring a competitive edge as INCO embarks on its second century of operation.INTRODUCTIONIt is not uncommon in milling operations to encounter a crisis. That is the point when the process does not behave as expected and fails to respond to the increasingly desperate efforts of the metallurgists and operators. Flowsheet and process changes are attempted and abandoned. With luck, one or more of the changes achieves some mitigation of the original problem or more usually, the original cause of the problem disappears. Regardless, the metallurgist can sit back and bask in the apparent success of his or her endeavours.Less common is when a problem is carefully diagnosed, a team put together to explore all avenues and recommend a path of action that is implemented on time, on budget and immediately delivers on the promises which are sustained over time. This is one such story. It is the story of the Mill Redesign Project at INCO’s Clarabelle Mill in Copper Cliff, Ontario.BACKGROUNDThe Clarabelle Mill was built in 1971 on the southern rim of the Sudbury basin. At that time it was one of four mills operated by INCO in the Sudbury area. During the 1970’s, 80’s and 90’s, the need for increased process efficiency, higher levels of sulphur rejection to tails and the concurrent development of high capacity mills and flotation cells, resulted in the consolidation of INCO’s Sudbury area milling operations into a single, expanded facility at Clarabelle."

Jan 1, 2003

By Brendan Reilly, Jon Isaacson, Paul McDermott

Kenny/Shea JV is constructing the water intake tunnel for the new Elm Road Generating Station, a supercritical coal-fired power plant in Oak Creek, Wisconsin, being built by Bechtel Power Corporation. The intake tunnel system consists of a temporary mining shaft, pump house and intake channel riser shafts, and four lakebed intake shafts. An 8.33 m diameter, 2,800 m long TBM mined rock tunnel is being constructed to connect the shafts. The intakes are located 2.4 kilometers offshore in Lake Michigan. The shafts and tunnel are being constructed in glacial tills and Silurian Dolomite. The estimated tunnel completion is December 2007.

Jan 1, 2007

By A L. Welsh, P S. Newling

Mill operators are entrusted to manage what are normally the largest capital assets on any mine site. Achieving maximum utilisation and lowest costs that drive operating margins are realised by applying well known fundamentals of good housekeeping and proactive (as opposed to reactive) maintenance programmes. Historically, maintenance and operations staff are bought in late during the construction stage and often do not have the time, know how or tools to put in place (let alone train the incumbent staff) a functioning maintenance system before commissioning starts. They then get drawn into a reactive maintenance paradigm as teething problems post commissioning are dealt with and day to day issues envelop the line tradesmen and supervisors. Additionally, even when some semblance of a planned maintenance system is established, it is often the case that over time personnel and cultural issues mask the development of problematic maintenance practices. As has been observed by the authors on many occasions, even when some basic programmed maintenance system is in place, the collection of maintenance data is often inaccurate, incomplete and not subject to analysis. The net result is of course a high incidence of machine failure leading to lower than expected availability, which ultimately translates to lower revenue and higher net maintenance costs. The time taken and the cost to repair a failed machine is always greater than the timely and planned repair of a worn machine.Upon review of a number of processing plants around the world, especially gold and small base metal operations, it is apparent that companies need to implement maintenance systems whereby the operators are not overwhelmed with data and can manage by exception. Inadequate or inaccurate data collection and analysis result in poor decisions being made and misguided actions taken. GR Engineering Services (GRES) has developed a system to enable the custodians of mining plant assets to make more effective and effective use of maintenance data by being able to focus on the indicators of plant deterioration and to programme concurrent maintenance activities to maximise plant availability and utilisation.This paper outlines the structures that can be employed to address the challenges of implementing a proactive asset management system. The best practice strategies described herein have been based on the fundamentals of a sound asset management framework:a phased approach to the development of Asset Management methodology and processeseffective implementation of programmed maintenance routinesmanaging asset condition data collected from various sourcesefficient analysis of asset data and management by exceptioninterfacing asset management data with Computerised Maintenance Management System (CMMS) and Electronic Management Systems (EMS) systemstips to assist with maximising asset performance.CITATION:Welsh, A L and Newling, P S, 2015. Operating strategies for custodians of company assets creating wealth, in Proceedings MetPlant 2015, pp 338–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Frederick H. Raab

An electromagnetic (EM) system for the location of trapped mine workers at coal-mine (300 m) depths has been developed. The use of such a system in deep mines (1-km depth) requires transmission at extremely low frequencies (ELF) and a reduction in the effective noise level beyond that which can be obtained by acceptable Integration times. Automatic-noise-cancellation (ANC) techniques reduce the effective noise level by combining several received signals that contain correlated noise. Such signals can be obtained either from a remote magnetic antenna or a local electric antenna. During Phase III of this program, real ELF noise data were acquired and used to test the ANC algorithms developed during Phase II. The ELF noise data were obtained from analog recordings made by Develco under another Bureau-of-Mines contract. Digitization was accomplished by an ND converter that was added to a GMRR computer. Phase III tasks Included preparation of software for digitization, computer-computer communication, data processing, and statistical analysis. Useable data were obtained from eleven half-hour tapes containing noise from one axis of the primary antenna and three axes of the remote antenna. The overall average Improvement in SNR was 4.1 dB. However, the average Improvements for the Individual X, Y, and Z axes were 4.2, 11.9, and -1.9 dB, which roughly follow the observed noise power. Nonlinear processing was not effective with this noise.

Jan 2, 1984

By T. N. Rushton

Rate minima are encountered in the reduction of magnetite with hydrogen. In a certain temperature zone, the reaction rate decreases with rise in temperature. This is inexplicable by classical kinetic theories; neither is a transition in reduction mechanism suitable for interpreting the observed behavior, This anomaly can be fully explained by hypothesizing two species of chemisorbed hydrogen with different adsorption coefficients and activation energies for adsorption. Competition between two energetic states of adsorption occurs with temperature rise, with the low energy state predominating below the anomalous temperature zone and the high energy state above it. The presence of two possible adsorption sites appears to be characteristic for oxidic adsorbents.

Jan 1, 1968

By Michel Robert

"In 1974, Copperfields Mining Corporation and Soquem formed a new company, Niobec Inc, to bring the niobium deposit of the St-Honore carbonatite into production.St-Honore is located in the Saguenay area, near the cities of Chicoutimi and Arvida, and about one hundred and forty (140) miles north of Quebec. The discovery of the carbonatite complex was made in the fall of 1967 as a result of an airborne radiometric survey in search of uranium. The detailed exploration of the carbonatite indicated two niobium-bearing formations besides the original discovery of a rare earths zone. During the following years, the niobium formations were defined by diamond drilling and a decline was driven down to obtain adequate samples for metallurgical evaluation. In 1974, after seven hundred (700) bench scale tests, eleven (11) months of pilot plant 2nd a worldwide market research, a joint decision was made to initiate the development of a fifteen hundred (1500) T.P.D. mine and mill, under the management of Teck Corporation. The construction of the facilities were completed in early 1976 both on time and within budget. Niobec is now the only north american and the world second largest producer of Niobium concentrate.The process used at Niobec was developed from the pilot plant programs and later modified by the mill personnel. A simplified flowsheet for this process is shown on the slide. Briefly, run of mine ore is crushed to minus 5/8"" and fed to a rod mill, ball mill, and screens circuit where the ore is ground to 92% passing 65 mesh. The ore is deslimed in two stages of cycloning, and the final cyclone overflow at 85% minus 11 microns goes to waste. The cyclone underflow is conditioned prior to flotation of a carbonate-apatite concentrate. This concentrate is cleaned twice and then pumped to tails. The carbonate rougher and cleaner tails are cycloned in two stages to change the process; water and then sent to the pyrochlore rougher flotation. The rougher concentrate is cleaned five times. This is followed by pyrite flotation to remove sulfur, leaching with hydrochloric acid to remove phosphorus and dyed to less than 0.1% moisture before being sent to packaging."

Jan 1, 1978

By J, T C. McCuaig, J Hodgkison, T Fouet

Olympic Dam is the eighth largest Cu deposit and the largest U deposit in the world, with approximately 35 million tonnes of contained Cu and 1.2 million tonnes of U. The most recent resource estimate was for 2.95 billion tonnes of mineralised material with average grades of 1.2 per cent Cu, 0.4 kg/t U, 0.5 g/t Au, 2.6 g/t Ag as contained mineral resources. Olympic Dam is expected to produce >200 000 tonnes of Cu and 4200 tonnes of U3O8 from 9.8 million tonnes of ore in 2004, making it the 12th largest Cu producer in the world. One of the impediments to achieving targeted rates of production has been oversize material (>0.9 m) reporting to stope draw points. A major contributor to oversize material may be overbreak along pre-existing structural weaknesses from stope walls and backs during the production life of a stope. Underbreaking to structures can also have a detrimental effect on the performance of a stope. In an effort to understand the influence of structural geology on stope performance, WMC Resources and SRK Consulting partnered during 2003 to refine the current system of structural mapping, and to use historical data to produce a structural interpretation covering a large part of the mining area. The interpretation has been wireframed in DATAMINETM into a three-dimensional structural framework model. To date, there are more than 600 structures of >50 m strike length incorporated into the structural framework model, which covers a study area 1500 m + 600 m + 350 m. A back-analysis exercise to assess the influence of interpreted structures on overbreak and underbreak was completed for laser-surveyed stopes.

Jan 1, 2004

Houston T. Aars Carter Mining Co. Sundance Rt. Moorcroft, WY 82716 Charles R. Ahlbrecht Western States Surveying Inc. 7030 So. Yosernite Englewood, CO 801 12 Dean Albon Monsanto Co. 800 No. Lindberg St. Louis, MO 631 67 Robert Anderson Mobil Oil Producing Inc. POB 17772 Denver, CO 8021 7 Stephen P. Antony Orbital Engineering 6789 So. Yosernite Englewood, CO 801 12 David Ariotti Boyle Mining Engineering Service Rt. 1 Box 15M Helper. UT 84526 Douglas Auck Falkirk Mining Co. 103 McKinley Ave. Underwood, ND 58378 Roger Backrnan N. D. Crockett & Assoc. 3467 Sorenson Way Salt Lake City, UT 84109 Richard Bailey Continental Conveyor & Equip. Co. 602 Park Point Drive Golden, CO 80401 Earl W. Baker Baker & Co. 4965 Jackson St. Denver, CO 80216 Allen P. Barber San Juan Coal Co. 705 Ocio Farrnington, NM 87421 Edward Barker Process Equipment Builders POB 7506 Paducah, KY 42001 Larry Barton Carter Mining Co. 101 5 Teewinot Circle Gillette, WY 82716 Hugh Bastian American Carbide Corp. POB 2650 Ronald N. Batdorf Monsanto Co. Box 701 Saratoga, WY 82331 Georgetown, KY 40321 Doris A. Bauer Mobile Oil Corp. POB 17772 Denver, CO 80217 Jan Beam Blount International Ltd. 2570 So. Dayton Way #E-308 Denver, CO 80231 Mac Beaudry Falkirk Mining Co. 1029 Cannon Ln. Washburn, ND 58527 R. C. Beerbower Gates Engineering Co. Drawer A Beckley, WV 25801

Jan 1, 1982

By Y. X. Zhao

This paper briefly describes the characteristics and induced factors of coal mining bumps based on the investigation of recent bumps accidents occurred in China. According to the theory of non-equilibrium thermodynamic and dissipate structure, the process of strain energy accumulation and dissipation in the ?Coal-Surrounding Rock? system (CSRS) is discussed during the preparation of coal bumps. In addition, a series of experiments are conducted to analyze the relationship between bump-prone property and micro-structural characteristics of coal. The process of coal bumps induced by propagation of fractures and deterioration of coal mass properties are also analyzed systematically.

May 1, 2009

By H. McIntire, R. Preston, D. Roberts

"Repeated 3D terrestrial digital photogrammetric surveys were conducted on hard rock mine pillars to characterize damage during secondary mining. Damage was quantified by measuring Depth of Failure, DOF, from spalling material and crack intensity, D21. These damage values were then correlated to visually assessed Pillar Damage Ratings and numerically estimated pillar loads. Measured damage, particularly Depth of Failure, correlated well with Pillar Damage Ratings. Numerical predicted pillar stress vs. damage exhibited the expected trend with shorter pillars being stronger. High resolution photographs and 3D models were also used to characterize damage mechanisms, which were found to be structurally constrained. INTRODUCTIONThe Doe Run companies Southeast Missouri Operations consists of six room and pillar lead mines (Brushy Creek, No. 29, Casteel, Buick, Fletcher and, Sweetwater) (The Doe Run Company, 2014). The mines are hosted in the Carbonates and Shales of the Viburnum trend with mining depths varying from 180 to 300 m. Pillars are commonly cut square with widths varying from 7 to 9 m and heights generally between 5 and 18 m, resulting in extraction ratios between 80 and 85% (Roberts et al., 1999). Figure 1 presents an idealized stratigraphic section through the Viburnum trend and Figure 2 shows a plan view of the five areas spanning the three mines included in this study."

Jan 1, 2015

A South African gold mining rock-related fatal accident database has been analysed in order to determine rock-related fatality trends in the gold mining industry over the period 1990 to 1998. This analysis was extended further to include some of the individual reefs mined and focused particularly on the Carbon Leader Reef, the Ventersdorp Contact Reef, the Vaal Reef and the Basal Reef. Rock-related accident locations are also presented. A stope rock-related risk is proposed, where the fatality rate in terms of rock-related fatalities per million square metres mined for the gold mining industry as a whole is compared to individual reefs, allowing a stope rock-related risk to be attributed to the individual reef. This comparison is extended further by removing the contribution by the reef being evaluated from the industry data, thereby allowing this reef to be directly compared to the rest of the industry with respect to a stope rock-related risk.

Jan 1, 2001

By Charles H. Simmons

Two versions of a VF transceiver to aid in location of trapped miners has been developed and tested. The belt worn model was produced in both transmitter and transceiver configurations. In addition, a quantity of the belt worn models were fabricated using aluminum wire instead of copper in order to reduce unit weight. Ten prototypes of a battery cap model VF transceiver were also fabricated demonstrating further unit size and weight reduction while maintaining electrical performance. Samples of- both versions were tested environmentally and the test data is included in this report. While both versions of the VF transceiver are similar electrically, and are constructed using convential manufacturing techniques, the battery cap model realizes a lower total weight, smaller volume and production cost than the belt worn version. Operationally, the battery cap model assures that the VF transceiver will always be with the miner.

Jan 1, 1981

By J. H. East, D. Harrington

"INTRODUCTION Considerable interest has been shown in the prospective use of Diesel-powered haulage equipment in both coal and non-coal mines. Foreign technical magazines have devoted considerable space to discussions of the use of Diesel locomotives in European mines and some mention of it has been made in technical papers in the United States. The Bureau of Mines has extensively tested the gases produced in the exhaust of the Diesel engine under various atmospheres and conditions of use; it has established a schedule of tests for permissibility of Diesel engines for use in underground coal mines, including, gassy or dusty mines.This publication provides information as to the successful use of Diesel-powered equipment underground workings in the United States and Europe, briefly discusses the characteristics of some of the toxic gases found in the exhaust of Diesel engines, and points out that Diesel-powered equipment can be used with reasonable safety in underground minus if necessary and entirely feasible precautions are taken."

Apr 1, 1947

By L Lachance, F Flament, D Leroux, S GariTpy

"Considerable metal values are often locked in stockpiles (ore, concentrates, heap leach pads, slags, reverts, etc.) and process equipment (bins, holding tanks, thickeners, etc.). This is more than enough to justify accurate accounting of such in-process metal inventories from both financial accounting and operational perspective. However, accurately determining the metal inventory of an in-process unit is often a challenge in industrial practice. Audits have shown that available indirect or direct measurements often carry large inaccuracies. Sooner or later, ignoring these measurement errors lead to unexpected incoherencies in reported metal balances. In such situations, coherent metal balances are then achieved through subjective and sometimes significant adjustments of in-process inventory levels. While such metal accounting methods applied by mineral processing engineers used to be rarely challenged, they are now being increasingly scrutinised by various stakeholders. Hence, metal accounting procedures that mitigate subjectivity in adjustments while still coping with the unavoidable uncertainty are more relevant than ever.This paper reviews three different metal accounting methods for reporting in-process metal inventory values. Their individual application strongly depends on the available measurements i.e. The indirect method where the metal inventory of a given process unit is determined by subtracting the cumulative reclaim from the cumulative feed carries important flaws. The direct method also comes with challenging accuracy issues so that emptying a process unit is often the best available inventory measurement. This reality is recognised for by further analysing a previously proposed operating mode where two interchangeable process units are alternately used. The third investigated method is the redundant method which combines indirect and direct methods for a given process unit. This paper reveals that the dual process unit operating mode and the redundant method can both significantly improve the estimation quality of in-process metal inventories.CITATION:Lachance, L, GariTpy, S, Leroux, D and Flament, F, 2013. Review of metal accounting methods for in-process metal inventories, in Proceedings MetPlant 2013, pp 102-117 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By P. G. Semple

"In January 1985, Equity Silver Mines Limited began operation of a cyanidation circuit to scavenge precious metals from the flotation tailings. At present, this process is treating 270,000 tonnes of tailings per month and is recovering in excess of 0.20 grams of gold per tonne. To obtain these results Equity is operating a carbon-in-leach circuit that utilizes pressure stripping, zinc precipitation acid washing and thermal reactivation. A cyanide destruction circuit is also required to minimize the deleterious effects on reclaim water in the flotation stage. This paper describes the existing scavenger plant, and details the start-up problems encountered and the modifications made to correct these problems.INTRODUCTIONEquity Silver Mines Limited , a 68% owned subsidiary of Placer Development Limited , is located 38 km southeast of Houston in north central British Columbia. The geographic location of Equity Silver Mines is shown in figure #1. In September 1980, production first began with the ore being supplied from the Southern Tail open pit. In March 1984, the Southern Tail deposit had reached its economic pit depth, and since then ore has been supplied by the Main Zone pit the gold mineralization in the Main Zone is less refractory than the Southern Tail and cyanidation of the flotation tailing appeared to be a viable alternative.An extensive test program was undertaken and the results confirmed that considerable gold and silver values were amenable to cyanide leaching. A feasibility study showed that these values could be economically recovered and the detailed engineering work began."

Jan 1, 1987

By C. Stoneback

The attapulgite industry saw a year of solid growth after a weaker 2003. Demand was up between 5 percent and 6 percent driven by almost all of the key markets. Construction continued to show record new housing demand, assisted by continued low interest rates. That drove strong growth in construction related markets like coatings, tape joint compounds and other construction materials applications. The agricultural markets rebounded modestly to increase sales for suspension fertilizers, animal feeds and pesticide carriers. Oil drilling also showed strong growth due to high oil and gas prices. Sales to molecular sieve applications grew due to petrochemical and construction demand. The export markets were assisted by further depreciation of the dollar. The only weak area was in nonagricultural granular sorbents, where other sorbent materials continued to dominate.

Jan 1, 2005

By Luis Castelli, Aldo Bonomelli, Giselle Schifferli, Claudio Zamora

"This paper introduces the operational concept and the description of a multi-site Remote Support Center for knowledge management and long-term process performance improvement.This centralized Support Center provides real-time monitoring of open-platform process automation systems, and on-line access to process data and control applications information for multiple sites.Considering that process automation is a key enabler to business performance improvement, sustaining effective performance benefits over time becomes essential. Unfortunately, changes in manufacturing process dynamics, technology obsolescence and in plant operational practices cause the control strategies to lose their effectiveness over time unless their performance is periodically evaluated, and if required, tuned to the new process conditions.A new concept in process automation is proposed through the addition of a new control loop based on performance analysis methodology which is intended to feedback process and automation operation information to system and process specialists, allowing for continuous manufacturing process improvement and sustainable production benefits through effectual control strategies.A remote support center can play a key role in the delivery of such services, by providing the base platform from which a comprehensive process overview and a centralized knowledge database can be executed and additionally, as an enabler for plant operational practices change.INTRODUCTIONA Benchmark on Automation Level in Copper Concentrators conducted by AMIRA in 2004, reported that the Codelco divisions scored below their peers in several categories.Codelco had thereafter been looking for a new automation concept, and had focused on process automation as a key enabler for process manufacturing and business performance improvement. The final decision was to create a strategic alliance with a world-class automation technology provider.The traditional approach based on isolated automation solutions/projects, showed that the control strategies benefits were decreasing progressively over time, because of the on-going need to adapt the control models to the ever-changing process conditions and different plant operational practices. Another consequence of this traditional approach was the wide variety of technologies and automation systems deployed in the different plant sites, with no common automation standards, and with low opportunities to transfer knowledge or practices."

Jan 1, 2010

By Yi Luo

Bolting the mine roof is one of the noisiest underground mining operations. The main contribution to the high noise is the drilling of the roof bolt holes, especially in hard rock. A previous research shows that the specific energy consumed in drilling the bolt holes is inversely proportional to the bite depth (i.e., penetration per drill revolution). Less specific energy at a reasonably high bite depth means less energy is wasted in the drilling process to produce heat, bit wear and noise. Therefore, control of drilling operation to achieve a higher bite depth can provide an opportunity to reduce drilling noise from its sources as a proactive noise control approach. In order to explore the feasibility and to develop the proactive technology for reducing drilling noise, drilling tests have been conducted in laboratory settings. The preliminary results show significant reduction in noise dose can be achieved by drilling in medium hard rock at a reasonably high bite depth. This paper presents the findings from the laboratory experimental studies conducted so far.

Jan 1, 2013

By W. Bryszewski

As a result of strategic analysis in respect of the needs for air quality management a new advanced and holistic approach to air quality management process was introduced in the North West Province (NWP) of South Africa. The process is based on the principle of co-operative management. It involves both active participation of all Interested and Affected Parties (I&AP) and the holistic approach to solving problems with the underlying principles of shared ownership and sustainable development. The process consists of the followings phases: ? Industrial process quantification ? Quantification of impacts ? Formulation of the required control measures ? Definitions of certificate conditions ? Implementation of an adequate compliance management system at company level ? Ongoing co-operative air quality and system management with the strategic objective of continuous improvements The system has been successfully introduced in the North Province and proved to be an effective management tool and aids assurance of sustained environmental ability to cope with the pressure of industrial developments. The benefits and effectiveness are discussed using Hernic Ferrochrome as an example. Hernic Ferrochrome is one of the first companies, which successfully implemented this system.

Jan 1, 2004

1. In 2003, a total of 1,972 coal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Coal mines comprised 13.7% of all mining operations. • Bituminous mines comprised 92.5% (n = 1,825) and anthracite mines 7.5% (n = 147) of coal mining operations. • More than 70% of all coal mines were located in three states: Kentucky (29.0%), West Virginia (20.9%), and Pennsylvania (20.2%). • Bituminous coal mines reported the production of over 1 billion coal tons.

Feb 1, 2005