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By M Korte, J McMaster, C Brent

The Barrick Osborne concentrator has gone through a number of upgrades since commissioning and has increased production from the original 119 t/h design capacity to a milling throughput of 265 t/h in 2008. This was achieved incrementally over several years, by maximising operating efficiencies, in order to minimise capital expenditure, and take advantages of economies of scale; but more importantly it was reached with no measurable loss of recovery. Osborne currently processes a blend of underground and open pit material from the nearby Trekelano deposit. Following primary/secondary crushing, the material is processed through a rod/ball mill grinding circuit ahead of rougher/scavenger flotation that produces a copper concentrate. Osborne was seeking a further increase in plant throughput of the order of 15 per cent, but at more sustainable levels of secondary crusher plant utilisation. In early 2008, Osborne contracted Metso Process Technology and Innovation (PTI) to review the entire process from run-of-mine feed to final copper concentrate. This review would be done concurrently with surveys of both the crushing/grinding and flotation circuits being performed at the same time. The outcome would be a steady-state model of the complete flow sheet allowing the crushing/grinding model to interact with the flotation circuit model, such that overall process optimisation was possible. This was to apply both by exploring the operating limits of the currently installed plant, as well as looking at the logical next stage of capital plant expansions. Surveys of the crushing and grinding circuits were conducted at the Osborne concentrator in May 2008. The main objective of the surveys was to review the potential of increasing grinding throughput whilst maintaining the flotation feed 80 per cent passing size. This would also require improving the efficiency of the crushing circuit which was already operating in excess of 80 per cent of the time. Steady-state simulations were performed using the developed circuit models to identify opportunities to increase throughput and alleviate high circulating loads in both the secondary crushing and grinding circuits. Due to operational changes, the recommendations resulting from this project were considered by Osborne but have as yet only been partially implemented.  This paper covers part A or the crushing and grinding component of the project. A separate paper discussing part B or flotation is also being presented at this conference. The results of interactive simulations between the flotation and grinding circuit models are included in part B of this paper.

Jan 1, 2009

By A. López-Valdivieso, M. A. Corona-Arroyo, M. Llamas-Bueno

Magnetite (Fe3O4) ore is concentrated by low-magnetic-field drums to recover a magnetite concentrate that is low in silica (SiO2). The presence of SiO2 in the magnetite concentrate for steel production increases the steel processing costs, so a major challenge in magnetic concentration is to lower the SiO2 grade in the Fe concentrate. This work presents studies that were carried out on the removal of SiO2 from the magnetite concentration at the plant scale. Studies were performed with a three 36 × 96″ drum unit processing 46 ton/h of rougher magnetite concentrate. These studies showed that silica appears in the magnetite concentrate by three mechanisms, namely SiO2 entrainment in Fe3O4 chains, heterocoagulation between Fe3O4 and SiO2 particles, and mineral locking of SiO2 to Fe3O4. The SiO2 entrainment mechanism had the highest contribution (75%) to the SiO2 recovered in the Fe concentrate. Electrokinetic studies on Fe3O4 and SiO2 showed that heterocoagulation occurs because of the low negative zeta potential of the minerals at the pH of the plant slurry. This study also showed that a high percentage of ultrafine size SiO2 particles trapped in Fe3O4 agglomerates was not removed by the dilution water for the slurry fed to the drum. To lower the SiO2 recovery in the drum magnetic concentration process, work should be directed towards the removal of trapped SiO2 in Fe3O4 agglomerates.

By A. D. Hunt

THIS PAPER will review Canada's fossil fuel situation as we understand it today and indicate some of the options available to meet our energy requirements during the next 15 years. It would therefore be helpful to examine Canada's total energy requirements and discuss the un certainties of the data base on which we must base future energy investment decisions. On the world scene, Canada is at the top of the energy-consuming nations, using about 49 bbls of oil equivalent per caput/ year. This appears to be slightly ahead of the U.S. and of course much higher than that of many countries. It is generally accepted that there is a more or less direct relationship between energy consumption and material standard of living. However , as we know, Canada, when compared with other industrialized countries on a GNP, an individual-income or some other standard basis, is lower in the list. This situation may be explained by our more severe climate and a relatively small population distributed over a land mass second only to that of the Soviet Union.

Jan 1, 1977

By T. G. Hawkins, T. M. Naciuk

"The Katie Cu-Au deposit is situated in southeastern British Columbia, 425 km east of Vancouver. The deposit is a member of the alkaline group of porphyry Cu-Au deposits associated with potassically and propylitically altered andesitic volcanic rocks.The Katie porphyry system occurs in mafic to intermediate alkaline volcanic rocks of the Lower Jurassic Elise Formation of the Ross/and Group. Host metavolcanic rocks include andesitic to basaltic flows, flow breccia, massive fine tuff and crystal tuff Gabbroic intrusions alternate with the volcanic rocks in drill core. The lack of chilled margins and shear contacts, as well as their similar composition to the volcanic rocks, suggest that the gabbro was synvolcanic.Alteration exhibits a zonal pattern spatially related to zoned porphyry-style mineralization. Propylitic alteration is common and assemblages consist of epidote, chlorite, sericite and calcite. Potassic alteration zones are accompanied by elevated copper-gold grades and are composed of K-feldspar, plagioclase, quartz, biotite and chlorite. Narrow drillhole intervals of secondary magnetite, generally less than 2 m across, occur above the potassic alteration zones. A thick oxidized cap lies above the mineralized zones, although only local supergene enrichment has been identified. The lack of supergene enrichment is perhaps due to intense near-surface fracturing and leaching from a high energy groundwater environment.Sulphide mineralization consists mainly of pyrite within the propylitic halo, and pyrite and chalcopyrite with trace pyrrhotite, sphalerite, tetrahedrite, bornite and molybdenite within the potassic alteration core. Malachite, azurite and traces of chalcocite occur within the oxidized cap.Discovery and exploration techniques have included airborne geophysics, regional stream sediment sampling, prospecting, geological mapping, ground geophysical surveys, soil sampling surveys, and diamond drilling. Two primary targets of porphyry copper-gold mineralization have been identified by exploration. The Main zone strikes northwest, has an apparent true thickness ranging from 70 m to 135 m, and is a minimum of 500 m in length. The 17 zone strikes northwest, has an apparent true thickness of 90 m, and is a minimum of 300 m in length. The two zones are defined by grades that generally exceed 0.2% Cu and 0.25 g/t Au. Both zones are open along strike and to depth."

Jan 1, 1995

By S. H. Ward

An account of a new method of investigating the electrical .properties J the earth's crust is presented. The method, called AFMAG, employs, as a source, natural alternating magnetic fields of audio and sub-audio frequencies. Measurements of the distortion of these fields caused by geological features are made with the aid of search coil detectors at several discrete frequencies. Many results of field surveys made with the method are presented and they illustrate its advantages and limitations when applied to the search for massive sulphide mineralization. The advantages far outweigh the limitations and in fact indicate that a major breakthrough in geophysical exploration technique and instrumentation has been made.

Jan 1, 1958

By E. R. Maize

[he scconG rcport of :his st?rI.org 8cdt with o3servatioi:s of conver- gence of roof an4 floor at t!x*re: ?.cc.-.tioris iri til~ ClVucible mine of kke Cru- cib1.o Fuel Co. Data on sl:'ociacnce ?.rd Lztcrcl mwe:~cnt cf the surface were .:lven for two of these areas, a-12 it was mentioned that ~lr~~ilar data were being obtained on a ?art of Pe:sc:rlvtzr.ia Fii~l?trr.y FE:, ~i!lic;l pcser: over the third area. 'I'hie hichw~ :LEO FasseE over t!lc ITenncoli::. :.line of the Bnckeye Coal Co. 9 milcs to ';he so-lth, cnd at P. l~tcr C'..att: ~.nr?r.,cc?r:cntS *.rere mnd.e to make similar observati on3 there. This y: pr mrnmri:.c n Czto obtnino? at those two locetionn,]

Jan 1, 1941

By L. M. Wang

Chengmenshan Copper Mine Concentrator adopts the new process of preferential?bulk stage floatation and utilize reground, largely increase the mineral processing index of the copper and the sulphide concentrates. In addition, the paper describes the remarkable economic benefit of the new process through the comparison of the new and the old processes.

Jan 1, 2014

By H. Tveit, E. H. Myrhaug, J. K. Tuset

Silicon metal as a commodity material is produced by carbothermic reduction of quartz in electric submerged arc furnaces, where CO2 forms as a by-product. Since 1997 the Norwegian Ferroalloy Producers Association have been engaged in research programmes aiming for reduced CO2-emissions associated with fossil carbon in their processes. One important issue has been to study how charcoal and wood chips perform compared to coal and coke in the silicon process. The ability of the carbon-rich reduction materials to react with SiO-gas is commonly assumed to be of large importance to the performance of the process. Based on laboratory experiments with different carbon materials, combined with estimation of parameters in a mathematical model of the reaction between carbon and SiO-gas, a foundation for a theoretical study of the performance of the carbon materials in a silicon furnace is established.

Jan 1, 2004

By Frank Armstrong

ALL the mining machinery of the Penn Iron Mining Co. has been operated by electric power for several years and when another shovel for stockpile loading was required the advantages of an electric shovel were naturally considered. After considerable study, serious objections suggested themselves the use of a shovel operated directly by electrical apparatus by reason of the complicated control, severe service on the motors FIG. 1.-ELECTRO-HYDRAULIC SHOVEL FIG:. 2-THE SHOVEL AS IT WAS OPERATED CINDER CONSTRUCTION. THE FIRST YEAR. and the heavy surges of current required from the line. It was finally decided to construct an electro-hydraulic shovel using water under pressure to perform all the necessary operations except that of propelling, for which a separate motor was best suited. A car body with boom, dipper handle and dipper of late design, but without any of the steam machinery, was purchased. A motor-driven centrifugal pump, a pressure tank, an air tank, a small air compressor and water cylinders with plungers, pistons and valves, were installed in place of the; steam equipment. Fig. 1 shows this shovel under construction and Fig. 2 shows it as it was operated during the first year, the summer of 1914. The large tank at the back of the car, in Fig. 1, carried air under

Jan 2, 1916

This summary of State laws or explosives was compiled primarily to ascertain what subjects relating to their control have been acted upon by each State legislature and, in general, how they have been treated. It does not include any legislation passed after 1942, or any proclamations, regulations, or administrative orders. It does not purport or attempt to be authoritative. If any problem arises involving interpretation of the statutes of any particular State, the original source must be consulted for the exact words used by the legislature. This summary, however, will be useful In determining whether relevant statutes exist, and In locating them quickly,-with a minimum of effort. It will be of value also in comparing statutes in one State with similar statutes in other States to determine what construction has been placed upon them by the courts of those jurisdictions or to contrast the varying provisions of many States upon a similar subject. To make these comparisons easier, the statutory provisions for each State have been grouped under several major topics in outline form. Although this sometimes has resulted in disruption of the continuity of individual acts, the increased general clarity and availability of comparable sections have more than justified the procedure followed.

Jan 1, 1943

By Alastair M. Lumsden

A study was initiated to examine the ways in which a number of foreign countries classify and regulate metal/non-metal mines which experience problems due to naturally-occurring flammable gases. Twenty countries were selected for study, and useful information was obtained from sixteen of these. Nine countries were visited (five of them twice) to hold meetings with representatives of government mine regulatory agencies and mine operators, and to visit mines encountering methane and other gases (carbon dioxide, nitrogen). In the later stages of the study seven gassy metal/non-metal mines in the United States were visited so as to provide a basis for comparison, and hence the evaluation of both the U.S. and foreign gassy mine regulations. In addition to obtaining copies of the mining laws and regulations of a number of foreign countries, nine foreign gassy mines, and the seven in the United States were documented in as much detail as possible. All this information is presented, along with appropriate conclusions and appendices. The study took two years and three months to complete.

Jan 1, 1983

By R. F. Droullard

The Bureau of Mines has used gross alpha and gross beta detectors to continuously measure radiation working levels for a number of years. During this time, improvements have been made in the design and performance of continuous working-level (CWL) detectors. This report discusses the improved designs and some of the operating principles and applications of CWL detectors in the measurement of radon daughter products in mines and dwellings.

Jan 1, 1985

By C. F. Winquist

The Bureau of Mines is engaged in research to evaluate the effects of cutter bit wear at coal mine faces. This paper addresses one element of conical bit wear, bit rotation. A discussion on mounting configura-tion and bit forces and their effects on rotation is presented. The effects on rotation and bit forces of bit attack angle, cutting depth, and skew are determined for two types of conical bits during linear cutting of sandstone-inclusive rock. The results indicate that a 10° negative skew angle and 35° attack angle produce the maximum rotation of 17.5° for each foot of cutting. Data on bit rotation and bit forces are presented in an appendix.

Jan 1, 1985

Jan 1, 1997

By R. Blickensderfer

The laboratory wear testing capabilities of the Bureau of Mines are described, Wear tests are used to support the Bureau?s research efforts toward reducing the wear of equipment used for mining and minerals processing and any wear involving a loss of strategic or critical materials. The emphasis is on abrasive wear because it accounts for most of the wear losses that occur in mining and minerals processing equipment, Spalling wear, caused by repetitive impact in grinding equipment, also is included, Ten abrasive wear tests, including high- stress and low-stress and two-body and three-body conditions, are described: dry-sand, rubber-wheel abrasive wear; Taber Abraser; abrasion resistance of refractory materials; dry-particle erosive wear; elevated-temperature, dry-particle erosive wear; low-angle slurry pot; jaw crusher gouging wear; ball mill wear; pin-on-drum abrasive wear; and high-speed impact gouging. Two repetitive impact tests are described: ball-on-block impact-spalling and ball-on-ball impact-spalling. Test equipment, procedures, and specimens are described, and typical test results are presented and discussed.

Jan 1, 1985

By George Hope, Brigitte Lacouture

"The Red Dog Mine has increased mill throughput for most years since startup. Although flotation equipment has been added over the last 10 years, the Red Dog metallurgical performance has been restricted by a lack of adequate flotation capacity. Two reduced tonnage trials conducted in 1997 as well as numerous SAG relines have consistently indicated the potential to significantly increase both zinc concentrate recovery and grade with additional flotation capacity. Late in 1999, a new circuit was designed with increased flotation capacity while simplifylng the current circuit, providing for three stages of dilution cleaning, and creating a retreat section. The purpose of the retreat section is to target the more complex particles and allow the chemical environment to be fine tuned for improved iron depression. In total, twentyone (21) Outokumpu OK50 mechanical flotation cells and four (4) 3.66m dia. column cells will be added to the current flotation circuit. The VIP (Value Improvement Program) Mill Optimization project is also addressing thickening, water treatment and power issues and has a total budget of $US105 M. Startup of equipment will be phased in to minimize the impact on current operations and is expected to be complete by the end of Q3-2001.INTRODUCTIONRed Dog Operations started production in November 1989. The mine is located above the arctic circle in northwest Alaska. It is linked by an 80 km road to a port-site facility where the concentrate is stored. Concentrate is shipped to markets throughout the world during the one hundred (100) days of open seas. Typical of sedimentary exhalative deposits, the metallurgy proved to be challenging and coupled with many mechanical shortcomings, the initial few years were very difficult. The start-up issues were slowly resolved and in 1998, a major grinding expansion, the PRI (Production Rate Increase) project, was completed. The project was designed to allow a 40% increase over the 1995 throughput. In 2000 mill throughput was 3,050,000 tonnes to produce a total of 960,000 and 140,000 dry tonnes of zinc and lead concentrates respectively, making Red Dog the largest zinc concentrate producer in the world. To address a shortage of flotation capacity remaining from the PRI grinding expansion, a project designated as the VIP (Value Improvement Program) Mill Optimization project was initiated. The mill optimization project is targeted to produce 1,100,000 tonnes of zinc concentrate at 56% zinc grade and 87% zinc recovery. The project will add twenty-one (21) Outokumpu OK50 (50m3) flotation cells, four (4) 3.66mO column cells and address water treatment, thickening and power generation capacities."

Jan 1, 2002

By D. Harrington

Near the close of the nineteenth century electricity was introduced underground, and the mining industry automatically was confronted with another potential source of fatalities and injuries to mine workers. Electricity has become an increasingly vital factor in the production of goal, particularly in recent years, because of the greatly extended mechanization that has taken place underground. The enlarged use of electrical equipment for cutting, loading, and hauling coal unquestionably increased the potentiality of shock and explosion hazards underground. Electricity may be used in coal mines with minimum danger if electric equipment and power-carrying wires are chosen properly and installed and kept protected by proper safeguards; on the other hand, if vigilance is relaxed in the slightest degree accidents may result. Electrical accidents are caused chiefly by direct contact with electrical equipment or power-carrying wires, by ignition of explosive gas or dust, and by fires of electrical origin. Electricity now ranks fourth as a cause of coal-mine fatalities, not including deaths from explosions or fires of electrical origin.

Jan 1, 1936

By G. S. Crawford

Forecasts prepared by the B.C. Research Council for the National Harbours Board suggest that mineral shipments through B.C. Lower Mainland port facilities will increase more than four-fold, from 6 to about 25 million tons, during the decade 1965 to 1975. The longer term outlook is for a six-fold increase to about 35 million tons by 1985. In 1967, minerais accounted for more than one-third of the total deep-sea traffic tonnage, nearly as much as grain. By 1975, the minerals' share will be about half the total. The principal items are exports of potash from Saskatchewan, and of coal and sulphur from Alberta and British Columbia. Additional exports include copper and other mineral concentrates and propane. Imports are chiefly salt and phosphate rock. Coastal traffic in such items as cement, sand and grave!, and limestone totalled 3.3 mil-lion tons in 1967. They will continue to be of major importance, but do not have the spectacular growth potential of the deep-sea traffic.

Jan 1, 1968

By K. H. McDaniel

People are our most valuable resource. It is as true today as any point in mining history as we face unprecedented personnel shortages aggravated by a workforce that is aging, significant generational gaps and difficulties recruiting younger professionals all amidst increasing global mineral demand. The educational system has a similar, but slightly contrary problem. Many historically strong mining engineering programs have died. Now, fewer mining oriented universities are trying to produce more students in order to meet the demand. Moreover, their situation is aggravated by a similarly aging workforce, a general lack of mid-career PhD?s with the interest and field experience to teach effectively, an extremely slow hiring and funding process, and an inability to be competitive against private industry compensation packages. The traditional instructional model, while not necessarily broken, is most certainly dated, and can penalize programs and students where schools do not have in-house expertise in a given topic. Mining companies, like Rio Tinto, have the opportunity, if not necessarily the obligation, to positively influence how this model works. Educational Partnerships may be the key. This paper will address some observations, and possibilities, associated with Rio Tinto?s efforts in this area.

Feb 23, 2014

Shane is enjoying his new work. Six months ago, he was stocking shelves at his local supermarket and decided to make the big move to a job in mining with more challenge and, of course, more dollars. He's been through his inductions, received his training tickets and is now working in a crew of eight underground at a fly-in, fly-out (FIFO) operation. There are many more systems and processes here than in his retail job, and Shane's comfortable that his safety is being looked after. He is enjoying the continually changing work and conditions, it makes the job interesting. It's taking some time to get used to the roster and he is worn out by changeover, but he gets more time with friends and family during R & R.   Generally, the mining industry has a maturing safety culture and well developed systems. This sometimes lulls people into a false sense of security. Safety systems cannot anticipate every possible situation, nor can they replace people's perception, thinking and decision-making. To manage safety, it's critical to find the right balance between dependence on systems and a healthy fear and respect of risks we face.   As safety standards are raised, systems tend to get more thorough and complex. When a new person joins a mining crew, we induct and train them to provide the information they need. As labour availability again becomes short, and many new people join our industry, we shouldn't assume they know the fundamentals. We need to explain not only what they are expected to do, but why doing what we ask and expect will keep them safe. We must equip people to deal with both the routine and the unexpected.   This presentation explores the challenges of balancing a structured, systematic approach to safety with the need to also equip people to deal effectively with risks everyday in dynamic and extraordinary situations.   Session purpose Introduce participants to a way of looking at risk from a different perspective, as a force for change and progress, if managed well. Demonstrate that risk is something we need to engage with emotionally as well as physically, if we want our risk management efforts to be successful. This purpose will be achieved through an entertaining and engaging presentation, using photos and case studies. The session will initiate interest to explore new ways of thinking about risk and generate discussion about the balance between people and systems. What is the right balance and why getting it right enhances the safety culture, while getting it wrong can impact on safety, business performance and sustainability.

Jun 1, 2010