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By F. Flynn, P. Downey, G. Ritson

"Bell Creek Mill which has been in continuous operation since 1987 has undergone numerous operational changes in the past three years. The addition of over 2. 5 million tons of resource at over 13 git from Hoyle Pond Mine precipitated an expansion program for the Bell Creek Mill. This paper discusses the major changes that have occurred over the past two years to increase throughput and efficiencies. In addition, the refractory ore treatment options are also discussed.IntroductionThe Bell Creek Mill is located in the Timmins Goldcamp approximately 8km NE of porcupine Ontario. (Fig I.)The mill was originally constructed by Camamax in 1987 to treat the Bell Creek ore at a design throughput of 350tpd. The flowsheet (Fig 2.) consisted of two stage crushing, grinding, thickening, leach and drum filtration with gold recovery by Merrill Crowe.As ore depleted at Bell Creek, the Mill was purchased by Falconbridge to process ore from their Hoyle Pond property. Kinross purchased the Hoyle Pond property and Bell Creek Mill from Falconbridge in 1992.The successful exploration program at Hoyle Pond has led to several expansions and process design changes, with further changes planned over the next twelve months.In 1994, the mine produced 61,865 oz. of gold at an average cost of 197US$ per oz. In 1995 production was 91, 611 oz. at a cost of 187US$ per oz. Projecting the nine months ended September 30, production for 1996 will be 155,000 oz. at a cost of 165US$ per oz.In early 1997, the CIP expansion will be complete, with a target of 175,000 oz. at a cost of 176US$ per oz for 1997. The mill throughput will have increased from 400tpd to 1500tpd between 1994 and 1997.The changes to Bell Creek since 1994 have been numerous with very little of the existing equipment still in operation. The total cost of the expansion to date is 15 million C$. This paper discusses the major projects carried out during in this time. The focus will be to highlight the justification of each project, the design and engineering, some of the initial start-up problems and solutions.Figure 3 shows a plan of the existing mill facility together with the various additions that were carried out."

Jan 1, 1997

In September, a fleet of 363-t (400-st) Liebherr trucks became operational in Brazil and have already begun moving iron ore in Para state. Prior to the arrival of the the trucks the Brazilian fleet relied on trucks up to 218 t (240 st). With the addition of the 363 t (400 st) trucks, the fleet has since experienced the high productivity offered by Liebherr T 282 B trucks.

Jan 1, 2010

By L. F. Heising

Ten composite samples of Mesabi Range nonmagnetic taconite from the Hibbing, Minn., area were evaluated by flotation and by reduction roasting-magnetic separation to determine their potential as a future source of iron are. Only one of the composites yielded concentrates that could be considered marketable, using as a criterion a 10-to-1 iron-to-silica ratio. Cursory petrographic examinations of all 10 composited samples and a detailed mineralogical study on 1 sample suggest that unfavorable mineralogical associations between iron and gangue minerals are responsible for their poor beneficiation characteristics.

Jan 1, 1967

By E. A. Clarke

The vapor-phase section of the Coal Hydrogenation Demonstration Plant at Louisiana, Mo., was operated for the first time in April 1949. The run lasted only 10 days because of time limitation (pending plant dedication in May) and the small amount of charging stock available. The primary purpose of the operation was to break in and determine the operability of the equipment and to supplement the operators' classroom training with actual practice by operating the plant under mild conditions. A secondary aim was to obtain data on the hydrogenation of petroleum oil and lignite tar distillate at approximately 10,000 p.s.i. while making gasoline and Diesel fuel oil. Although the operations were carried out under conditions considerably below those used in the plant design, a great deal of experience and data was obtained. As it is not feasible at this time to conduct further vapor-phase operations on similar stocks, this report has been prepared to present and summarize the data obtained through this operation.

Jan 1, 1950

By Gilles Recher, Jörg Riechers, Albert Lueghamer

"INTRODUCTIONIn view of a global trend towards urbanization, more and more trunk sewers and combined sewer overflow tunnels (CSO) with medium to large diameters and the corresponding link sewers are currently built and under design. Shielded tunnel boring machines using segmental lining as tunnel support represent an efficient solution for construction of new wastewater and supply tunnels. Especially in the field of sewers, the durability of concrete structures both exposed to any groundwater present on its exterior and to aggressive waste water as well as gases on its interior is a key requirement. Despite thorough research on segmental lining and mechanized tunneling machinery, conventional thermoplastic liners show comparatively minimal progress in terms of practical advancements. This is in contrast with the development of the latest segment embedded high density polyethylene (HDPE) system. Based on experiences achieved, this paper discusses the latest development of an integral protective lining system in respect of material characteristics and its adaptability to both project and customers’ demands. Reviewed performances, as the bondage behavior of the embedded HDPE system at axial stress loads due to acting thrust cylinders during ring build as well as the ability to drain pressurized water behind the embedded membrane, tested at full scale segments, are also presented. The paper is round off by presenting first details of sewer projects endeavoring to utilize this cutting-edge solution for an integral concrete protection, which will be commenced beginning of 2016.CASE HISTORIES ENCOURAGE ADVANCEMENTS Past experience has shown that unprotected concrete surfaces as well as chemical based linings such as coatings, sprayed linings and cured in-place-systems cannot reach the desired life times. Also the fact that in deep tunnel sewer system hardly maintenance is possible, a durable and maintenance free system is required which only can be reached by applying mechanical anchored HDPE (CPL)."

Jan 1, 2016

By Seth K. Martin, Tony Nichlany, Alan R. Poeppel, Konstantinos Syngros

"This paper presents a case study on bored pile construction in challenging karst conditions below a supertall building in Kuala Lumpur. Innovative design and construction techniques helped keep the project moving through very difficult and unpredictable geological and drilling conditions. The development encompasses about 12,400 square meters and includes a 77-story tower, a 59-story tower, a five-story podium, and four contiguous basement levels. The site is underlain by a residual soil derived from a siltstone/claystone (the Kenny Hill formation), then limestone bedrock. Subsurface conditions are relatively uniform within the Kenny Hill and highly variable at the limestone surface. Extreme cases included 40-meter-tall underground caverns, 40-meter-tall pinnacles, and a 50-meter-tall underground rock ledge. Local piling practice in Kuala Lumpur involves deriving pile capacity entirely in the Kenny Hill formation to avoid the unpredictable limestone surface. However, the massive tower foundation loads and relatively shallow bedrock required the piles to be socketed in the limestone. The 77-story tower will be supported by 2.0- and 2.2-meter-diameter bored piles 50 to 100+ meters long, socketed in limestone, with working loads between 40 and 70 Meganewtons. Two Osterberg-cell load tests were used to develop a site-specific rock socket skin friction correlation with RQD. Exploratory rock probes were drilled at each pile location to design the rock socket length based on the rock quality and sloping rock conditions. The rock mass was pressure-grouted during each rock probe to improve the rock quality and fill voids in the rock.INTRODUCTIONThe Kuala Lumpur City Centre, home of the Petronas Towers and the world’s deepest foundations, will be the future home of a new supertall tower. The 77-story tower will be supported by a piled-raft foundation that relies on piles terminating in the highly erratic, karstic Kuala Lumpur limestone formation. The high building loads coupled with relatively shallow limestone across the majority of the tower footprint forced the piles to extend into the limestone."

Jan 1, 2016

By Norman R. Ball

"Many people in the mining and metallurgical industries were brought up to embrace Henry Ford's pronouncement that ""History is bunk"" but it is not generally known that the same Henry Ford created and paid for one of the finest technological museums in the Western World. I am aware that many people feel that industry history is something you ask aging executives to do or that history is a clip-andpaste compendium of pictures re-discovered every 25 years or on the occasion of issuing a press release on plant expansion. Moreover, there are many who fear historians as somewhat deranged individuals interested only in corruption, injustice and sensational labour strife. Good history lies somewhere between the controlled P.R. handout and the hysterical attack. Writing good history is a difficult creative act based on the application of experience, insight, wide knowledge and careful reasoning to available evidence. To date, the Canadian mining and metallurgical industries have achieved a great deal but left too little evidence and it is this lack of evidence which must be corrected before it is too late. It is the purpose of this article to stimulate thoughts with regard to archives, one of the more important vehicles for the preservation of such evidence."

Jan 1, 1999

By R. Buisman, K. Reyneke, M. Fullam, J. V. Brown

Most mineral processes currently in use, such as flotation, spirals, gravity concentrators, etc., are only effective over a small range of sizes, hence the upstream need for technology to accurately classify fines by size. The Pansep’s design is revolutionary. Slurry is fed onto connected mesh sections that move without bending or vibration, in a circular motion. Both sides of the screen mesh are utilized, so Panseps are self-cleaning and has half the footprint of other mesh-type screens. Developed in South Africa in 1997, the Pansep has proved itself very effective as a wet fines screen to effectively classify fine mineral fractions from 50 to 2,000 micron (325 to 10 mesh).

Jan 1, 2001

By J Tiihonen, J OÆCallaghan, T Haakana

Outotec is today capable of providing technologies, process equipment and engineering for the construction of pressure oxidation leaching (POX) plants in any location in the world. Outotec works with customers from mine to pure metal, participating in plant design from the process development phase (including test work execution/supervision) to plant commissioning and operations. Either key equipment technology packages with basic engineering or entire POX plants can be supplied.The addition of pressure oxidation equipment to OutotecÆs product portfolio adds to and complements already existing significant experience in general hydrometallurgical process and proprietary equipment design and supply.In addition to providing key pressure vessels, piping and valves to a POX plant, Outotec can offer an enhanced and proven autoclave agitation system that maximises oxygen mass transfer and utilisation. Novel energy and water recovery technology can also be tailored to a customerÆs specific needs. Importantly Outotec owns and operates extensive test work facilities and can provide test work to ensure the optimum POX flow sheet and materials of construction. Outotec ensures that best available technology (BAT) concepts are used in POX design to improve the availability of the process and minimise unpredicted shutdowns.CITATION:Tiihonen, J, Haakana, T and OÆCallaghan, J, 2013. Outotec pressure oxidation - more out of sulfide ore, in Proceedings World Gold 2013 , pp 197-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

A concise country-by-country summary of the mineral industry of Africa is presented. Reserves, resources, role of the country in the world mineral supply, and developments in the mineral industries are reviewed. The data on each country are accompanied by a map showing mineral location and transportation facilities.

Jan 1, 1976

By P. Malíková, I. Osičková, R. Sousedíková, P. Rys, J. Dvořáček, S. Heviánková

Each mining project goes through the same life-cycle, from prospecting and exploration to closure and post-closure periods. This prompts the question whether the closure of a mine constitutes the end of its life-cycle or whether the decommissioned mine can be employed for some other purpose. Best-practice references indicate that there are many viable options. In our opinion, the production of service water is one such option. Laboratory research was carried out on the water from a flooded underground coal mine in Ostrava- Karviná coal district, Czech Republic, concerning the production of service water from pumped minewater. The research proved the practical feasibility of service or process water production. Given the effect of global climate change with regard to water resources, good prospects for this additional resource can be assumed since the water has to be pumped in any case for safety reasons.

Oct 1, 2022

By Gerald T. Homce

Data from the U.S. Bureau of Labor Statistics show that 89 water well drillers died on the job between 1992 and 2002, and 28 of these deaths were electrocutions (Figure 1). In fact, elec­trical accidents are the leading on-the-job killer of water well drillers. The use of electricity is such an integral part of our lives that we usually take it for granted, but if we don?t understand or choose to ignore the hazards associated with electricity, the results can be deadly. Why is electrical shock so dangerous? If the voltage (of a shock) is sufficient to drive electrical current through your body, just 10 milliamps of cur­rent (1000 milliamps = 1 amp) can cause muscles to contract and prevent you from releasing an energized wire or tool in your grip. As little as 30 milliamps of current can paralyze your breathing, and 75 milli­amps can cause your heart to stop pumping blood (ventricular fibrillation). As a comparison, a small bedroom night-light draws about 30 to 60 milliamps. Other factors influence how severely you?ll be shocked if you touch a live electrical circuit, such as the path electrical current takes through your body and how long it flows, as well as your body weight. How much voltage is needed to drive electrical cur­rent through your body? Not much! Generally, any power source at 50 volts AC or higher is considered dangerous.

Jan 1, 2008

"The most common comminution testing methods and the associated analytical procedures provide average values and do not capture the variability in breakage behaviour of ore particles. Therefore, plant designs and process performance predictions use only average values; hence, the inherent variability that exists within an ore domain translates into variation in process performance. This paper discusses the drawbacks of using the average approach to impact comminution testing and plant design. It considers breakage intensity from a single-particle testing perspective. To clearly delineate breakage behaviour of each broken particle, an experimental technique using the JK Drop Weight Tester (JKDWT) has been developed by which actual comminution energy per particle and breakage intensities were measured directly. Four different ore types in ranges of -45+37.5mm and -22.4+19mm were tested at three energy levels of 0.1, 0.25, 0.5 kWh/t and six energy levels of 0.5, 1.0, 2.0, 2.5, 3.0 and 4.0 kWh/t, respectively. Sieved results of individual particles, notionally, t5, t10 and t50 showed the presence of large variability in their breakage behaviour, which was not captured by the standard JK impact breakage testing approach. In addition, the original JKMRC model is modified by introducing a third parameter, ‘Emint10’ which describes the minimum energy required to produce the minimum percent t10 for a given ore type and its significance is tested statistically. These results suggest that the analysis of breakage variability may lead to more robust plant designs. Perhaps, the most useful insight from this work is to extend single particle breakage model developed by JKMRC to a comminution percentile envelope which may provide a more detailed picture of ore breakage variability. INTRODUCTION Rock consists of mineral grains, pores, voids and cracks that may differ markedly in size/density which make rock a heterogeneous material by nature. The degree of heterogeneity in rock affects its breakage characteristics where these variations increase local differential strain and stress within a stressed rock (Scholz, 1968) and it depends on many factors such as rock genesis, alterations, etc. One important aspect of this heterogeneous feature is presence of a large amount of experimental scatter in rock breakage results when considered from a quantitative perspective (Bieniawski, 1967; Liu, Roquete, Kou, & Lindqvist, 2004)."

Jan 1, 2018

By E. J. Murphy, A. P. Rowles, John C. Holtz

"INTRODUCTION The use of sheaths or hollow cylinders of flame-extinctive materials surrounding cartridges of permissible explosives has been developed during the last few years; the history of sheathed explosives in their salient development in Belgium was treated recently in a publication of the Bureau of Mines. 6/ This development is of great interest in explosives technology, for it holds possibilities of reducing further the ignition hazards that may cause many coal-mine disasters. The township interest in sheathed explosives in this country is attested by the passage of some State laws permitting the use of such explosives on shift 7/; inquiries are received in increasing numbers concerning the effects of sheaths on practical hazards as well as the general technology underlying their use."

May 1, 1943

By W. C. Goldberg, E. M. Frizzell

Monitoring slope displacement in open-pit mines can help predict collapses and prevent serious damage, injuries, and fatalities. Early detection of movement may indicate the need to modify slope geometry, initiate dewatering if the slope is wet, or consider artificial support measures such as cable bolting. Slope monitoring at the Berkeley pit was carried out with varying degrees of intensity and continuity for about 15 years. Some of the old mine records are still intact and accessible. Slope monitoring data can therefore be collected and published for the benefit of other mine operators. Because prediction of slope failures is empirical in nature, publication of several well documented case studies will be a valuable contribution to the industry. Background - Berkeley pit Open-pit mining of copper from the Berkeley pit, located on the east side of Butte, MT, began in 1955 and ceased in 1982. During that time, about 1 Gt (1.2 billion st) of material were removed to form a pit about 1.8 km wide by 2.1 km long (6000 ft by 7000 ft) at the rim, and 550 m (1800 ft) deep as measured from the high hill on the northwest side. From the south side, the pit only measures 365 m (1200 ft) deep. The Berkeley pit was first owned and operated by Anaconda Minerals Co., and subsequently by Arco. Following its closure in April 1982, the mine began to fill with water. Washington Construction purchased the property in 1986, and Montana Resources Inc. began mining to the east of the Berkeley pit in July 1986. Numerous instances of slope failure were recorded during the course of mining and several intensive geotechnical investigations were conducted in an effort to optimize the mine design. One of the last and most comprehensive studies was initiated in 1977. For purposes of geotechnical analysis, the mine was divided into nine design sectors on the basis of geologic conditions, geographic orientation, and economic importance (Fig. 1). Only two of these sectors - the concentrator and the southeast corner - are considered here. Material properties were obtained from several studies of samples collected from the mine and adjacent areas. The slope was monitored using standard surveying techniques to record the amount of movement in an area. The

Jan 1, 1989

By J Folwell, G Phillips, F Gassner

Geomembranes selected for various applications often start with considering target properties developed by industry organisations such as Geosynthetic Research Institute (GRI), and test methods developed by ASTM and other Standards organisations The geomembrane types are typically, initially selected based on manufacturers recommendations and chemical resistance data from the manufacturer or industry knowledge. Geomembranes considered for this project included materials with material properties that exceeded the minimum target values of various test methods. The difficulty is in selecting which parameters are most important for a particular application and also what service life can be expected for the geomembrane under various chemical and environmental exposure conditions. Accelerated aging testing of candidate geomembranes in simulated exposure conditions can be useful to select the preferred geomembrane and predict the service life of the geomembrane under different exposure conditions. The exposure conditions of immersion in acidic tailings liquor, splash zone and freeboard zone were considered for evaporation ponds on a site with significant heat and UV radiation. Candidate geomembranes considered a range of different types of polyethylene liners. The results of the accelerated aging testing have allowed the selection of the geomembrane for the range of exposure conditions and evaluation of the expected service life of the geomembrane.

Jul 1, 2021

By Martin Walker, Joseph Ang, Jongwon Lee, Alvin Bayudanto, Lilian Lorincz, Morteza Khorshidi, Wenyong Rong

This paper presents a case history of liquefaction susceptibility evaluation study for a major infrastructure project in the San José area. The subsurface material of the study area consists of Holocene alluvial deposits composed of interbedded and crosscut clays and silts, sands and gravels. The simplified approach for liquefaction triggering evaluation was carried out using both CPT data and SPT data representing site’s seismic capacity and the peak ground acceleration associated with a return period of 975 years at ground surface representing seismic demands. Site-specific cyclic stress ratio (CSR) profiles as seismic demand are also estimated from one-dimensional site response analysis. The simplified approach uses empirical depth stress reduction factors (rd) based on generic shear wave velocity profiles to account for the non-rigid response of the soil profile in estimating CSR. The CSR profiles of the simplified procedure were examined by completing site response analyses using site-specific soil profiles to represent site-specific seismic demands in the liquefaction triggering evaluation. The paper concludes with a comparison and discussion of the liquefaction evaluation examining results from CPT versus SPT data, and the comparison of CSR profiles from the simplified procedure versus site-specific response analysis.

Sep 8, 2021

By G. A. Brown

"Mining executives are becoming increasingly involved with decisions of the ""What would happen if ... "" variety. Potential changes in government policy, such as tax incentives, E.G.M.A. allowances, etc. affect the economic future of present and proposed mining ventures.This paper will discuss various measures of effectiveness normally used in assessing this future, such as discounted cash flow, etc., and will describe means of introducing uncertainty into the computations. As the recognition of risk and attitudes toward accepting it are very important in the life of a mine executive, there will be a brief discussion of utility theory and its application to risk analysis.Risk models are usually of a size to warrant the use of an electronic computer. Therefore, to demonstrate the simple interaction necessary between a financial analyst and such a model, data will be read into a remote computer from a time-sharing terminal in the meeting room. It will be shown that changes may be rapidly made and alternative policies investigated ""on line"" to a computer."

Jan 1, 1970

By James C. Duchon

The use of extended workdays (regular shift lengths of 10 or 12 h (hour), while still maintaining a 4O-h workweek) in mining operations is attracting growing interest in the United States. There is very little doubt that extended workdays is a very popular alternative among the work force because of the significant increase in days off, including weekends, especially when compared with traditional rotation schedules of working seven straight shifts or having only one weekend off every 4 to 6 weeks. However, there are some serious concerns by management, workers, unions, and various governmental policymakers that working 10-or 12-h days may create an added risk of accidents and health problems. The U.S. Bureau of Mines reviewed the literature studies related to the safety and performance issues of extended workdays. This report presents a summary of those findings. The studies examined in this review are divided into three sections: (1) laboratory, (2) field, and (3) accident and injury analysis. In general, results are inconclusive. Studies have shown both positive and negative effects. It is concluded, therefore, that in industries such as mining where accidents are a serious concern, special measures and evaluation in the use of extended workdays be considered.

Jan 1, 1994

By J. B. Hadaway

The operation at Phu Kham commenced design and construction in early 2006 and was commissioned in May 2008. This paper will examine and discuss the project from the inception of flow sheet development and equipment selection, equipment design and manufacture, construction, commissioning and ramp up to full production. The paper will touch on the strategies employed to achieve a short schedule and the efficient use of capital, but with the main emphasis on the grinding circuit. Various challenges during the early years of operation will be discussed including the effect of ore characteristics, including competency, on the performance of the grinding circuit. Actions to overcome these challenges and to enhance performance will also be discussed. Finally, current and future plans to improve the performance of the grinding circuit and the overall plant will be summarised.

Jan 1, 2012