Search Documents

By K. K. Murray, D. G. Gelderland

"The pressure oxidation autoclave at the Goldcorp’s Red Lake Gold Mines (RLGM) was commissioned in 1991. Since commissioning, the circuit has been well maintained and its capacity increased to mechanical and gaseous oxygen limitations. With advances in available technology, opportunities to produce more sulphide concentrate and a changing business environment, an optimization project has been initiated at RLGM. A multi-phase approach has been developed to optimize both the operations and economics of the circuit. This paper describes the history and future of the autoclave circuit at RLGM.AcknowledmentsWe would like to thank the operations and maintenance staff at Red Lake Gold Mines for their support and openness of mind to enact changes to enhance the operation. We would also like to acknowledge the members of the integrated team from Red Lake maintence, metallurgy, operations and corporate technical services that did the hard work to push past the status quo in order to advance productivity.OpportunityThe Red Lake Gold Mines (RLGM) pressure oxidation (POx) circuit has been in operation for over 25 years processing the high sulphide content gold bearing minerals. Increased sulphide concentrate production from improved flotation recovery and increasing gold sulphide association at depth has led to the POx circuit becoming a throughput bottleneck. The opportunity exists to process increased tonnages of sulphide concentrates and increase gold production. In order to realize this value, it will be necessary to increase the throughput capacity of the POx circuit.BackgroundThe POx autoclave at the RLGM, commissioned in 1991, was Canada’s first gold autoclave. It was installed to replace the two-stage fluid bed roaster that was built when the Campbell mine and mill were constructed in the late Forties. The circuit was originally designed to process 12.5 t/d sulphide sulphur in about 50 t/d of Campbell flotation concentrate. Following the merger of the Campbell and Red Lake Mines in 2006, the POx circuit started processing flotation concentrate from both Campbell and Red Lake Mills. In recent years, the circuit has been processing about 18 t/d sulphide sulphur in 75-85 t/d flotation concentrate."

Jan 1, 2017

Small scale gold mining operations in Papua New Guinea (PNG) have been observed to use very low flow rates of water in sluice boxes. In a series of laboratory experiments carried out to determine whether this approach was unsatisfactory or not for their situation, indications were obtained that it had some advantages in the recovery of fine gold but at the cost of considerable throughput. The separation mechanisms operating in such a system are analysed.

Jan 1, 1986

By Christopher C. Jobes, Alan G. Mayton, Timothy J. Matty, Joseph P. DuCarme

Mining injury statistics show that a significant number of back, neck, and head injuries are linked to exposure from vehicle vibration. Use of a suspension seat is a common way to isolate the vehicle operator from the adverse effects of vibration exposure. Thus, researchers at the National Institute for Occupational Safety and Health1 – Pittsburgh Research Laboratory (NIOSH – PRL) performed laboratory studies on four passive and two semi-active seat suspension designs. These are typical of seat suspensions commonly found on large off-road heavy surface mining, construction and agricultural vehicles as either replacement or original equipment manufacturer (OEM) systems. One included a pneumatic (air bladder) spring mechanism. The fifth and sixth suspensions were a NIOSH magnetorheological (MR) semi-active damper design based on the pneumatic (air bladder) and one of the coil spring suspensions above. These suspensions were modified with a commercially available MR damper substituted for the OEM damper. These six seat suspension systems were tested and analyzed, for vertical vibration only, using the ISO 5007 Standard [1]. This paper describes the laboratory vibration tests using a MTS® shaker table and discusses the results obtained for the different suspension designs and highlights the rheonetic technology studied. Implications of the seat suspension designs relative to their capabilities for isolating vehicle operators from vibration exposure are discussed. Results for suspensions 1 through 3 showed frequencies of isolation from 2.1 to 3.0 Hz using the 40-kg (88-lb) mass and from 1.65 Hz to 1.8 Hz using the 80-kg (176-lb) mass. Suspension #4, in tests with only the 80-kg (176-lb) mass, showed an isolation frequency of 3.7 Hz. With the MR damper added to seat suspension #4, the peak transmissibility was lowered from 1.3 to 0.95 and showed a corresponding downward shift in frequency from 2.25 Hz to 1.4 Hz. In fact, the results for suspension #5 (the MR damper added to seat suspension #4), using test #3 conditions of the programmed control algorithm, showed isolation (attenuation of transmitted vibration) throughout the test frequency range from 1.0 to 6.0 Hz.

By I. S. Parrish

This article offers one of the infrequent looks at Chinese mining. It includes a brief review by Parrish of a tungsten symposium held there and his comments on and impressions of the mines he visited. In early Oct. 1981, a Symposium on the Geology of Tungsten was held in the Peoples Republic of China. There were approximately 100 participants. Half of them were Chinese. The remainder included representatives of the United Nations, geologists from other nations in Southeast Asia, and 10 invited specialists from other countries. The invited guests included K.F.G. Hosking of the Camborne School of Mines, United Kingdom; C.S. Hutchinson of the University of Malaysia; K. Mattson of LKAB Int. AB, Sweden; T. Kwak of Latrobe University, Australia; K. Sato and S. Ishihara of the Geological Survey of Japan; M. Clarke of the Department of Mineral Resources, Indonesia; P. Bateman of the US Geological Survey; and the author. R. Horsnail of Amax was also invited but was unable to attend because of delayed visa clearance. The meeting was noteworthy because the Chinese were presenting more than half the papers. In addition, following the formal session, everyone was taken to the famed Jiangxi tungsten district and toured four mines there. Organization and Background The idea for a symposium on tungsten geology was brought up in late 1979 during a visit to China by the Economic and Social Commission for Asia and the Pacific (ESCAP) and, in particular, by members of the Regional Mineral Resources Development Centre (RMRDC) of the United Nations. Discussions continued and in the spring of 1981 invitations were sent to selected geologists throughout the world. China's Ministry of Geology handled arrangements, scheduling, and logistics. Travel to China and all correspondence before the symposium were coordinated by the Bandung, Indonesia Bureau of RMRDC. All costs in China were met by the Peoples Republic of China. Airfares and "per diem" enroute for participants were paid by respective governments, sponsors, or individuals. On Oct. 10, visiting participants entered China from Hong Kong. The author and a few others traveled by train to Guangzhou (Canton). Most of the group flew in the next day. The entire group was then taken to Nanchang, traveling by sleeper train and arriving on Oct. 11. The symposium group stayed at the Kiangsi Hotel, where the meetings were held. Meetings Oct. 11 was a day of orientation and rest. The group was taken to an art museum and treated to a Chinese opera movie. The formal meetings began on Monday, Oct. 12. Simultaneous translations aided presentations, though more than half the Chinese speakers delivered their talks in English. The acoustics and sound system were excellent, and the Chinese provided 35-mm and overhead projectors. There was no screen, however, and the yellow, painted wall that was used detracted from projection clarity. In general, the Chinese papers were detailed, thoughtful, and professional. Some, naturally, were stronger than others. Taking them as a unit, one derives the following sequence to the Chinese approach to tungsten exploration: (1) Geologic investigations with mapping at a scale of 1:200,000 accompanied by only minor geochemical or geophysical work. (2) Geophysical investigation with regional gravity and magnetic surveys directed toward identifying deep, tectonic systems and seeking granites in thick, crustal environments. (3) Geochemical sampling in-

Jan 6, 1982

Updraft sintering of lead concentrates was introduced at Port Pirie in 1955 and since that time a considerable amount of investigational work has been carried out in the laboratory and on the plant with the objective of improving both the understanding of the process and its practical application.From this work it is now possible to predict trends in design and operation, which should result in capital savings and increased efficiency of future updraught plants.INTRODUCTIONOver the last 70 years a remarkable advance has been made in the method of preparing lead concentrates for smelting in the Port Pide blast furnaces of The Broken Hill Associated Smelters Pty. Ltd. (RH.A.S.). Beginning in 1889 with heap roasting, the process progressed to Ropp roasters and Huntington-Heberlein pots in various combinations, then to multiple small Dwight Lloyd (D.L.) downdraught machines. In 1940 two large 10 ft by 50 ft D.L. downdraught machines were installed, and finally in 1955 updraught sintering was ,introduced with the installation of the present 10 ft by 99 ft sinter machine.At the time this last machine was built it was the first unit of its type and thus, of necessity, an experimental machine. During the eight years it has been operating a considerable amount of investigational work on sintering has been carried out both on the plant and in the laboratory.It is now felt that sufficient information is on hand to predict at least tentatively, some of the future developments in lead sintering, whereby both the quality of the sinter and the rate of production may be improved. This will result in a considerable reduction in smelting costs.

Jan 1, 1964

By Jun Lu

There are many factors affecting the strength of pillar, including width-to-height (W/H) ratio, mechanical properties of coal and surrounding rocks, property of partings in the coal, and the interface property between coal seam and the roof/floor. In this paper, the effect of varying pillar?s width-to-height ratio (W/H=3, 5, 7, and 10) and coal/rock interface cohesion (Cj =50 psi, 150 psi, and 300 psi) on pillar strength has been studied. The confinement effect of W/H ratio and interface shear strength is investigated by studying their effects on the average minimum principal stress developed in the pillar. The deformation behavior of the coal pillar is investigated. It is found that the pillar?s transition from strain softening to strain hardening behavior depends on its W/H ratio and the interface shear strength.

Jan 1, 2008

By J. Ling, L. Racine, P. Cousin, A. R. Laplante

"The problem of gold recovery by gravity from high density gangues is first discussed from a fundamental perspective. Three potential difficulties are presented: poor liberation and fine gold particle size, concentrate bed erosion by coarse dense particles, and slow percolation of gold particle through the high density gangue bed. Two case studies are presented to illustrate the impact of these three problems on circuit performance and the feasibility of gravity recovery. It is concluded that careful testing can determine the scope of the first problem and feed preparation can limit the extent of the second. The third problem is clearly the most serious and results in lower gravity recoverable gold recoveries than would be achieved with the same recovery effort on a low density gangue application.IntroductionSince the commercialisation of the Knelson Concentrator in 1980, gold gravity recovery has experienced a surge in interest, in Canada and the United States first, then Australia, Zimbabwe and Russia, and finally worldwide. Table I details number of units sold in various countries, which corresponds approximately to their importance as gold producers 1. Exceptions. such as the low rank of South Africa or the importance of Zimbabwe, despite the much higher gold throughput of the former, are generally the result of differences in the effectiveness of the local marketing strategies, as well as a reflection of the ""philosophy of recovery"" prevalent in the country.The impact of the Knelson has not been felt equally in all plants. Typically, a highly successful application falls into the following categories: (a) alluvial or hard rock recovery for which gravity is the sole recovery method, (b) hard-rock free gold milling with ores which have a very high gravity-recoverable gold (GRG) content, (c) low grade sulphide copper-gold ores which include flotation ahead of cyanidation and (d) free-milling gold ores ahead of Other applications can be successful, but are not as common. The ""explosion"" of centrifuge concentration, of which the Knelson is the most successful but by no means the sole model, has created a certain euphoria which can be summarized as ""gravity recovery will improve the profitability of gold milling, no matter what."" This presentation is about applications that are not so successful, or even downright unsuccessful. The rationale is not to down-play gold gravity recovery, but to set it in its rightful position: metallurgically, it is not appropriate all of the times; it can become inappropriate if poorly designed; and it can be metallurgically possible but economically unjustifiable. In this paper, this will be illustrated and explained rather than demonstrated, with the use of both industrial plant surveys and laboratory test work. Alternate gravity approaches will be suggested."

Jan 1, 1997

By W. G. Pariseau

This contribution describes rock mechanics features of the Davis Cavern at the former Homestake Mine in Lead, South Dakota, U.S.A. The mine is located in the northern Black Hills of South Dakota. In 2003 and again in 2008, the mine site was recommended for development as a national Deep Underground Science and Engineering Laboratory (DUSEL) in cooperation with the Sanford Underground Science and Engineering Laboratory under the South Dakota Science and Technology Authority (SDSTA). The original Davis Cavern was excavated about 9.1x16.8x9.7 m high (30x55x32 ft high) in 1965 (Mitchell 2009) at a depth of 1,478 m (4850 ft). The purpose of the cavern was to house apparatus for detecting solar neutrinos. The experiment ultimately proved successful and earned R. Davis a share of the 2002 Nobel Prize in physics. Recently, a new experiment (LUX=Large Underground Xenon detector for dark matter particles and WIMP's=weakly interacting massive particles) was proposed for the Davis Cavern that required an increase in height of 2.4 m (8 ft). For many years, the Homestake gold mine was the deepest operating mine in North America. Development extended to the 8000 Level (2,438 m). The mine closed in 2003. Pumps were shut off and the water level rose to the 4350 Level, about 150 m (500 ft) above the Davis Cavern. Some six years later after selection for DUSEL proposal development by the National Science Foundation (NSF), access to the 4850 Level and the Davis Cavern was regained. Pumping has lowered the water level to well below the cavern floor. Figure 1 shows the layout and location of the Davis Cavern (Cavity). Detector tank, supporting steel, and so forth were subsequently removed. The cavern was re-supported and new access was developed. By August, 2010, 13,000 ft3 had been removed during enlargement and renovation of the Davis Cavern. Figure 2 shows the detector tank under construction in 1965.

Jan 1, 2012

By Flor De Cock

The paper reflects part of the work from the European Regional Technical Committee on Piles (ERTC3) during its mandate between 1994 and 1999, and, in particular, describes the find­ings from an International Seminar held in 1997 in Brussels on European practice for design­ing axially loaded piles. The seminar included contributions from 17 European countries, each of which provided a synopsis of their respective national design approaches. This paper pays particular attention to the design methods based on laboratory and in-situ test data for both bored and displacement piles.

Jan 1, 2002

By Mike Fabius

The Lakehead Region Conservation Authority is responsible for slopes along the Kaministiquia River, one of the largest tributaries to Lake Superior in Canada. After arresting toe erosion for a mile of riverbank, the remainder of the slope required stabilization to stop further crest regression and to protect the houses, street and services at the top. Stabilization of the 100 ft. high slope was tendered as design-build with a target safety factor of 1.3 and a design life of 75 years. The successful bid was a system of 1.4 inch diameter soil nails up to 40 feet long, installed perpendicular to the slope on a 3 to 5 foot grid. The conventional shotcrete facing was replaced with a ?green? biotechnical facing and special transverse plate heads on the nails. The key to keeping costs low proved to be installation with light equipment working on the slope, and driving the nails without drilling or grouting. Rather than tension, the design was based on bending in the nails, similar to a laterally loaded flexible pile. The paper describes the design and installation of this innovative system. The design is discussed in terms of soil properties, nail resistance as it varies with depth, failure modes, corrosion protection, root design and nail head design. Construction challenges are discussed. The system is compared to an adjacent anchored soldier pile wall built along the same slope 20 years ago. Post construction monitoring results confirm predicted performance.

Jan 1, 2006

By W. Hermanson

This report presents the results of a task to complete a final design of a remote controlled hi-roof bolting machine for high roof areas in coal mines. The project was begun by visiting several coal mines to become familiar with roof fall areas. Several machine concepts were generated and presented to the design committee for criticism. A preliminary design was completed, as covered by this report. A Final Design and Final Report will be issued incorporating the committee comments at the Preliminary Design review and comments received concerning this Preliminary Design Report.

Jan 1, 1979

By Fred Leonard

This report is principally concerned with the engineering and economic feasibility of area surface coal mining systems other than draglines. This analysis evaluates shovel/ trucks, shovel/crusher/conveyors, and shovel/rail excavation and haulage systems for an assortment of geologic environments and production rates in the Powder River Basin (PRB) Shovel/trucks, front-end loaders/ trucks, and shovel/crusher/conveyors were studied in a multi-seam, dipping geologic area of the Four Corners Region. The Texas lignite engineering and economic research involved bucket-wheel excavators (BWE), BWE/backhoes, and scraper/backhoe combinations for overburden and coal excavation. The PRE truck/shovel study utilized the most recent computer simulation available in both the design and cost analyses. Detailed engineering analysis, followed by in-depth operating costs (operating and depreciation) result in a complete evaluation of each mining system. Cost comparisons of the different mining systems under similar geologic and production constraints are presented in the report to illustrate the estimated capital investment and production costs per ton of coal and bank cubic yard of overburden.

Jan 1, 1980

Agenda ?Trends in Wireless Technology ?Success and Opportunities ?Improving plants efficiency ?Improving plants reliability ?Improving plants safety and security ?Wireless Ecosystem ?Lessons Learnt / Recommendations Why Wireless? ?Lower cost (no wiring cost) ?Flexibility (no wire) ?Standards-compliant wireless devices major factor enabling growth:?Standard WLAN (IEEE 802.11)?Wireless field I/Os (IEEE 802.11, ISA100.11 and WirelessHART) ??Wireless adoption will become a milestone that will rival the introduction of Fieldbus and the distributed control system (DCS) in its importance.? ARC Advisory Group

May 1, 2009

By AIME AIME

THE following Officers, Directors, and guests were present: Herbert Hoover, A. R. Ledoux, Henry S. Drinker, Edwin Ludlow, Samuel A. Taylor, Charles F: Rand, William M. Corse, Arthur S.. Dwight, Glen H. Clevenger, L. W. Francis, F. G. Cottrell, Bradley Stoughton, Percy E. Barbour, E. P. Mathewson, Dorsey A. Lyon, Archibald Douglas, A. D. Flinn, RobertLinton, James F. Kemp, William Y. Westervelt, J. W. Richards, W. L. Saunders, George Otis Smith, Thomas T. Read, J..C. Murray, Ralph Arnold. A Committee on Mine Equipment was appointed composed as follows: Graham Bright, chairman, William Kelly, Howard N. Eavenson, R. E. Hobart, and S. P. Rumsey. B. D. Saklatwalla was added to the Committee on Miscellaneous Metals and W. Spencer Hutchinson was added to the Committee on Mining Geology. A revised budget for 1921 was approved. A petition duly signed to amend Section 1., of Article III of the Constitution, increasing the initiation fees from ten dollars to twenty dollars, was approved by the Board.

Jan 1, 1920

By R. Mohan Srivastava

"The goal of estimation is considered in the light of decision analysis. A simple example reveals the essential elements of decision-making in the face of uncertainty. A second example shows that these elements are also key features of many mining decisions. These two examples cause us to revive an old probabilistic notion that the goal of estimation should be to quantify what is unknown. The conditional probability distribution provides the complete statement of one's uncertainty. Once the conditional probability distribution has been established, one should retain as an estimate the value which minimizes some objective loss function. A third example shows how the ""best"" estimate depends on the chosen loss function. Current practice is almost exclusively based on the least squares method, which assumes a loss function which penalizes underestimation and overestimation equally. This is unfortunate not only because symmetry is an unrealistic assumption but also because mining offers a rare opportunity to state the loss function directly in terms of profitability. Both the theoretical framework and the practical tools exist to allow us to reconsider the conventional notion of the ""best"" estimate. IntroductionThis paper looks at estimation in the mining industry from the point-of-view of decision analysis. Virtually all decisions depend on estimates since few of the important parameters are ever known exactly. In this paper we will be referring mainly to the estimation of ore grades, though the approach discussed here is generally applicable to any decision in which relevant information is uncertain.In the first section we look at a very simple example of decision-making in the face of uncertainty. We will then tum to a mining example and see that the essential features of the simple example still pertain. From these two examples it will be clear that the decision analysis approach rests on two key concepts: the conditional probability distribution and the loss function. A third example demonstrates how different loss functions produce different ""best"" estimates from the same conditional probability distribution. In the final sections we willexamine the current practice of estimation in the mining industry. Though the tools for estimating the conditional probability distribution already exist, a change in the way we think about ""best"" estimates is needed. Very little attention is presently paid to the loss function even though it is readily available in many mining applications."

Jan 1, 1987

By Tiago Nunes Lima

As propriedades mecânicas de ligas TiNbSn são dependentes do processamento termomecânico. O refinamento dos grãos das ligas é obtido através de processos de conformação a frio, atingindo valores de redução que podem estar acima de 80%. Esta deformação a frio permite o aumento das propriedades mecânicas, mas pode reduzir consequentemente a ductilidade e a tenacidade das ligas. Este estudo tem como objetivo observar o efeito da laminação e forjamento a frio nas propriedades mecânicas de ligas Ti35Nb2Sn com 80% de redução. Foram realizados ensaios de tração, dureza, metalografia e microscopia das fraturas. Ambas as ligas deformadas e envelhecidas apresentam as fases ß, a” e ? em suas microestruturas, porém, com algumas mudanças microestruturais. Foi notado que a liga forjada possui maior resistência máxima a tração e dureza que a liga laminada.

Aug 16, 2017

IN presenting a'description of milling and treatment methods at the Waihi mine, it is advisable to first traverse a good deal of the past history of the mine, and show the various steps which have led up to present-day practice. The record of the company is one of steady, solid advancement, both in metallurgical and financial results. This is illustrated by the following figures, dating back from 1897...

Jan 1, 1912

By Frederic Masse

With widespread acceptance in the market place, many engineers are choosing ground improvement techniques to provide suitable foundation subgrade at sites that would have traditionally required deep foundations. This paper discusses the Controlled Modulus Columns (CMC) ground improvement technique and some case histories highlighting the use of this technique for retail development sites. CMC are a sustainable and cost-effective ground improvement technology that transmit load from the foundation to a lower bearing stratum through a composite CMC/soil matrix. The CMC installation is also an attractive option from an environmental perspective because it utilizes reverse flight augers, which displace the soil laterally. This installation technique achieves two goals: it densifies the soil around the CMC, which improves load transfer into the element and avoids spoil and its disposal. Through the introduction of two cases histories, we will present the key benefits of the CMC technology. Each case history will clearly illustrate how a CMC solution can reduce the overall cost of a project when compared to a more traditional type of deep foundations. They will also show how the use of CMCs has benefits that relate to the overall sustainability of the project. While CMCs are an attractive financial and sustainable option, they have also demonstrated that the performance of the system is comparable to that of deep pile foundations. Because CMCs are a relatively new technology many potential users are not aware of its benefits. While we discuss the use of CMCs to support buildings in this paper, CMCs also have been used for a variety of other applications including foundations for tanks, mechanically stabilized earth (MSE) walls, and embankments

Jan 1, 2011

By Paul S. Goodman

Volume II The purpose of this study is to explain reasons for the productivity differences in mining crews. The literature on group productivity is examined. Then a new approach to estimating productivity differences is proposed and estimated across seven different mines. The results indicate a fairly robust model in terms of explanatory power. Recommendations on how the model can be used as a managerial tool are presented.

Jan 1, 1985

By Chikaosa Tanimoto

INTRODUCTION Bratislava is located at the intersection of important traffic routes, including motor-ways, roads, railways, air traffic, trading, and inland waterway with an important harbour. The construction of the D2 Motorway Bratislava, Lamacska cesta Stare grunty was the last missing section of D2 Motorway and its completion linked the Czech Republic through Bratislava to the Hungarian Republic. Traffic was obliged until its completion to use the Lamacska Road and Mlynska Dolina, which were the most heavily trafficked roads in the city. The section of D2 Motorway to be completed in 2006 was 3,300m in length, of which the SITINA Tunnel was approximately half the length. After putting into operation the transit traffic(motorway) and urban traffic was separated. Transit traffic by passing the town was eased. The junctions D2 with Lamacska Road (Harmincova) and Mlynska Dolina also allowed better use of the motorway for the urban traffic The tunnel construction was specified by the features with the highly weathered and thermally altered granitic rock formation with the overburden of Quaternary sediment of 2?4 m thick, very thin overburden, severely controlled deformation limit and environmental protection. The tunnel had to be excavated beneath and nearby the academic complex area and the zoo, where sensitive facilities exist and animals live in. The tunnel consisted of two tunnels (Tunnel A and B) with the length of 1,415 and 1,440 m, respectively. The overburden thickness was in the range from 10?30 m. The standard cross-section and the one with invert arch were 79.5?81.5 m2 and 92.1?93.3 m2. The excavation took 21 months from September 2003 to May 2005. The construction was based on the concept of NATM. The SITINA Tunnel was the third application of NATM in Slovakia, following the BRANKISKO Tunnel (commenced in July 2003) as the first and the HORELICA Tunnel (in October 2004) as the second NATM practice. To protect the surrounding structures and citizens from tunneling operations, seismic monitoring was performed in association with blasting. The allowable limit of blasting vibration was fixed to be under the particle velocity of 15 mm/sec. The tunnel excavation cleared this limit as expected before construction. In driving through the difficult geological situation the excavation work hit 49 faults, and some of them occasionally caused serious face instability. In principle, the rock formation has been affected by the high hydrothermal effect and the resultant clay filing along faults and joints. The auxiliary reinforcement with the 4?8 m long pipe roofing was needed to protect the vicinity of mining face area. This operation extraordinarily required additional works and time which had not been expected before construction.