Search Documents

By T. A. Chepushtanova, I. U. Motovilov, V. A. Luganov, G. D. Guseynova

"Kazakhstan has significant reserves of oxidized nickel ore with low nickel content. Processing of such ores is effective via pyrometallurgical technologies such as smelting to ferronickel or matte with consecutive extraction of metals from melting products. There are also many options for direct hydrometallurgical processing. However, they do not provide high nickel recovery.We studied extraction of nickel and cobalt by using combined technology of low-grade ore processing from the Shevchenko Kazakhstan deposit, which includes smelting to poor matte followed by hydrometallurgical processing of the matte. The nickel content in the initial ore was 0.75–0.9%. Pyrite concentrate of Sokolov-Sarybai Kazakhstan deposit containing 0.17% cobalt and 0.06% nickel had been used as a sulphidizer at smelting.As a result of the study, we were able to extract up to 98% of the nickel and up to 80% of the available cobalt. Obtained matte contained 3.1% nickel, 0.29% cobalt, 71.6% iron and 24.3% sulfur. Matte leaching was carried out by hydrochloric acid. The iron content in the pregnant solution was 170–185 g/dm3. Nickel and cobalt precipitation from the pregnant solution was carried out by hydrogen sulfide. Initial matte or cast iron was used as neutralizers during the process. Practically complete precipitation of nickel was achieved at 3–5% excess of neutralizer at 333–343°K in 4 hours; up to 95% of cobalt precipitation was achieved in 50% excess of neutralizer at 363°K in 8 hours. The purified solution contained 200–600 mg/dm3 of nickel, 80-100 mg/dm3of cobalt and 175–185 g/dm3 of iron. The purified solution allows to obtain iron oxides by high-temperature hydrolysis, and to regenerate hydrochloric acid.As a result of non-ferrous metals precipitation we obtained sulfide concentrate with concentration of Ni up to 25% and concentration of Co up to 5.5%. The technology is recommended for semi-industrial testing."

Jan 1, 2016

By R. D. Brown

For the first time in years, the spring budgets of federal and provincial governments have not brought down major new proposals affecting the tax burdens of the mining industry in Canada. It seems appropriate to use this unaccustomed period of tranquility to set out an extremely abbreviated summary of the principal features of the federal and provincial income and mining tax rules affecting the mining industry.

Jan 1, 1977

By L. A. Kaufman

"AbstractThe Bureau of Mines, Ottawa, in conjunction with Eldorado Mining and Refining (1944), Limited, has developed an automatic concentrator for uranium ores.A brief review of radioactivity is given which shows the present limitations for obtaining •good results by electronic concentration. The ores after being mined, or at any other stage of a concentrating process, can be analysed for the uranium dissemination and from these results the possibility of an economical concentration can be estimated.The electronic and mechanical parts of the equipment are described. Difficulties in the operation's, and means by which they have •been and are •being overcome, are discussed. The capacity of the units, the results obtained, the man-power required, and other pertinent data are presented. Simple control analysis on the percent U3O8 has been developed.Research is continuing along lines to develop a more completely automatic unit using a scintillation detector, and applying a few new ideas and some devices that have been developed in colour sorting.IntroductionIt is well known how important the Geiger counter is in the field of exploration for uranium. It was in late 1946 that Dr. C. Lapointe, of the Bureau of Mines, Ottawa, first started work on an automatic picking unit to concentrate uranium ores. He used the principle that if a number of pieces of unknown ore, some of which contained uranium, were individually brought up close to a Geiger-Müller tube, then the pieces containing uranium could •be easily picked out due to their activity. Since then a good deal of work has been done by the Bureau of Mines in conjunction with Eldorado Mining and • Refining (1944), Limited, to develop an electronic concentrator."

Jan 1, 1950

By J. J. Denny

The purpose of this paper is to present, briefly, an outline of Canadian practice in the milling of gold-bearing ores- not, however, including those auriferous ores which are mined and milled primarily for their content of some other metal. It is not the writer's intention to offer technical data, nor to discuss any particular phase of the metallurgy, but rather to give a general résumé of past and present methods. As it is only within recent years that gold milling has assumed prominence in Canada, much of the technology is modern, and detailed articles describing the practice adopted in the several mining districts, and recording the various changes and innovations that have been made from time to time, are to be found in the Transactions of the Canadian Institute of Mining and Metallurgy, and in the mining journals. Prior to the year 1860, any gold that had been produced in Canada had come from placer operations in British Columbia, but ' during that year lode gold was discovered in Nova Scotia, in quartz veins, and in several localities mines were opened and small mills of very simple character were erected to treat the ore. These plants, equipped with stamps, or arrastre, were only effective in recovering the free gold. Concentration and chlorination were introduced in an endeavour to save the gold occurring in intimate association with metallic minerals, but, due to various circumstances, gold mining and milling did not progress in Nova Scotia.

Jan 1, 1930

By Nick Vayenas, Ming Cai, Hongbin Zhang Lorrie Fava, Enrique Acuña

"A hybrid methodology is proposed to improve the accuracy of Diesel Particulate Matter (DPM) concentrations simulated in a ventilation network model by using Computational Fluid Dynamics (CFD). DPM, as a primary concern for underground hard-rock mines, has been studied in two dominant numerical models, ventilation network solvers and computational fluid dynamics. Ventilation network solvers are efficient, but they are not able to provide three-dimensional DPM concentration contours and only accept area-average DPM data as input. CFD simulations are time-consuming, but generating DPM concentration results with high accuracy. Besides, both monitoring points and planes can be created in a CFD model, which can take both point data and area-average DPM data as input. The hybrid methodology is intended to combine the advantages of the two by using the CFD results to update the network model results at key locations. A field study was conducted in a dead-end heading in an underground gold mine in the United States. Real-time DPM monitors were used to collect data. A CFD model and a network model were built for the experiment area. The CFD model was calibrated to the experimental data. In the study presented here, results from a calibrated CFD model are converted to equivalent diesel emission rates in the ventilation network model at a shared outlet. The hybrid methodology is used to provide better input for the network model. INTRODUCTION Mine ventilation system is one of the most important parts for an underground mine. It not only provides fresh air to the personnel but also helps clear the contaminants generated from the diesel-powered equipment. For most underground metal and non-metal mines, diesel particulate matter is the main contaminant. It is also the focus of this paper."

Jan 1, 2019

By J. A. Herbst

Professor Klaus Schönert and his students used fundamental physics to develop many of the principles required for the design and scale-up of "Gutt Bett Zerkleinern" devices such as the high pressure grinding roll (HPGR) or the high pressure roll crusher (HPRC). As the equipment evolved so have the tools used for its selection and analysis. In the current paper discrete element modeling (DEM), Metso's proprietary Fast Breakage simulations, and Schönert's packed bed piston test are combined with energy based population balance models (PBM) to yield an alternative to ore characterization and equipment selection by pilot plant testing. The resulting methodology is used to take the next step in understanding these devices with a view toward predicting plant performance. This paper describes a journey beginning with precise modeling of a small HPGR including stud geometry and system hydraulics. A key to predicting performance is the accurate modeling of individual particles, their motion in the machine, the probability of breakage and redistribution of fragments, and the inter-particle breakage events that occur between the rolls at different pressures, speeds and moisture levels. Advanced DEM simulations and particle breakage characterization methods provide the necessary technology. The resulting combined models were validated using a small diameter laboratory scale unit. The validated physics based model was used then used to predict the performance of plant scale units using a specific energy based scale-up method. Scale-up results are analyzed in terms of power draw, throughput, and discharge product size distribution.

Jan 1, 2012

By G. Kolosay, J. Rajala, G. Deschênes, A. Romanov

ABSTRACT: The Kupol project, located in Far East Russia, treats a high-grade, free-milling ore containing 25.5 g/t Au, 298.3 g/t Ag, and 0.5% pyrite,with a P70of 53 microns. Most of the gold occurs as elec-trum and the silver is predominantly present in the forms of acanthite, stephanite, pyrargyrite, andproustite. The mill reached the design throughput of 3,000 tpd six months after start-up. AKnelson con-centratorrecovers10.4% gold and 0.5% silver. Leaching (14.5 hours pre-treatment and 116 hours cyanidation)of gravity tailings is performed with the CANMET Enhanced Leach Process (CELP),using only 490 ppm NaCN (cyanide consumption of 1.1 kg/t). The precious metals are recovered by counter-current decantation and the Merrill-Crowe process. Calcium hypochlorite destroyscyanide and thiocyanate. Overall, gold and silver recoveries for 2008 were 95.4% and 85.6%,respectively (2.8% and7.5% higher than targets). In the first eight months of 2009, gold and silver recoveries were 95.0% and82.6%, respectively. By August 2009, the mill processed 1.42 million tons of ore with production of 1.1 million ounces of gold and 11.3 million ounces of silver. CELP performance was not affected by changes in feed grade and ore mineralogy. Additional modifications to the leaching strategy allowed further reduction in cyanide consumption and effluent treatment costs.

Jan 1, 2011

By P. G. Dunn, J. Fitzgerald

ABSTRACT The scheduling of underground mining activities is a complex task that must simultaneously satisfy a large number of constraints. A schedule optimization tool (SOT) for underground mine planning is described, and its use for investigating strategic decisions is illustrated through a case study. The maincomponents of the SOT include (a) a genetic algorithm that searches for optimal schedules, (b) guidance for the application of heuristic rules, and (c) sliding, which implements just-in-time development. Findings indicated that preliminary scheduling performed before invoking the SOT, intended to provide a good starting point for the search, did not ultimately lead to higher value schedules.

Jan 1, 2010

By Z. Luo, China University of Mining & Technology, C. Duan

"The magnetic separation removal rate of pyrite could be improved effectively by increasing the susceptibility of pyrite. The electromagnetic characteristics and absorption response performance of high-sulfur fine coal were studied in strengthening the susceptibility of pyrite. In the process of treating the sample through the microwave, electromagnetic energy could be converted into heat energy due to dielectric loss and magnetic loss. The RL(dB) was evaluate the performance of absorption response of coal. The microwave improved the susceptibility was in ultra-high frequency region, which is the most natural resonance. The absorption fine coal to microwave was strengthened and microwave energy was improved by adding the magnetite powder with double loss characteristics as the microwave absorber. The dielectric properties and permeability characteristics of the fine coal trend were investigated by maxing magnetite powder. The microwave absorption in different coal thickness was surveyed through the reflection of energy loss.INTRODUCTIONMicrowave desulfurization is one of the most important research directions (Haque, 1999; Makul, Rattanadecho, & Agrawal, 2014; Su, Tang, Zhang, Jing, & Bai, 2014). The working principle of microwave absorption response can be briefly described as the interaction of the sample with microwave energy, which will result in the microwave energy converting into heat energy loss (Keangin & Rattanadecho, 2013). For specific samples, the polarization effect includes multiple polarization mechanisms(Meikap, Purohit, & Mahadevan, 2005). Different polarization mechanisms have different occurrence time and dominant mechanisms. Meantime, energy consumption will be occurred during the process of polarization effect (Chelgani & Jorjani, 2011; Rowson & Rice, 1990) . The absorption of microwave energy in the fine coal is a process of electromagnetic response (Znamenácková, Lovás, Mockovciaková, Jakabský, & Briancin, 2005). Microwave transfers the electromagnetic waves into the heat energy by microwave dielectric loss and magnetic loss for achieving the absorption of microwave energy in the treatment of samples (Lee, Kim, Kim, Chung, & Kim, 2004). The additive magnetic medium is Fe3O4 belonging to microwave energy absorber of double loss medium (Uslu, Atalay, & Arol, 2003)."

Jan 1, 2016

By Bern Klein, Tichang Sun, Daozhen Gong, University of Science and Technology Beijing, Chunbao Sun, Stefan Nadolski

"This paper is focused on the effect of modifying the SAG mill/ball mill transfer size on the energy efficiency of SABC circuits. The transfer size is considered to be a parameter which provides operators with the opportunity to improve comminution circuit performance. In this study, the Moly-Cop tools package was employed to predict the energy consumption of SAG mill and ball mill circuits under different operating conditions. An Energy Benchmarking model was adopted to calculate grinding energy efficiency. The SABC circuit at the Huckleberry mine was selected for this case study. It was observed that after increasing circuit transfer size (T80) from the existing 3.3 mm to 4.8 mm, the Benchmark Energy Factor (BEF) of the SABC circuit decreased from 4.30 to 4.05. In terms of energy consumption of the SABC circuit, 1.17 kWh/t of specific energy saving was achieved through the transfer size optimization.It was also observed that when a transfer size was selected such that both SAG mill and ball mill circuits operated at their highest energy efficient states, the entire SABC circuit was the most energy efficient. The maximum energy efficiencies of these three circuits were all approximately 25% when compared to the minimum practical energy required to carry out an equivalent comminution duty. Single-particle compression breakage testing was used to determine the minimum practical energy associated with the Huckleberry mill feed. In combination with geo-metallurgical data, this study also provides an opportunity to perform dynamic optimization of SABC circuits."

Jan 1, 2016

By M. Imani, A. Fahimifar, A. H. Javid

"Current studies of bearing capacity for shallow foundations tend to rely on the hypothesis of an isolated footing. In practice a footing is never isolated; it is mostly in interaction with other footings. This paper focuses on a numerical study to evaluate the ultimate bearing capacity for two interfering strip footings resting on a rock mass in which the strength can be described by the generalised Hoek–Brown failure criterion. This criterion is applicable to intact rock or heavily jointed rock masses that can be considered homogeneous and isotropic.The material is assumed to exhibit perfect plasticity and obeys an associated flow rule. The effects of Hoek–Brown parameters including GSI, mi, and sci were studied and the corresponding results are presented. For different clear spacing (S) between the footings, values of the efficiency factor (?) were determined; where ? is defined as the ratio of the failure load for an interfering new footing of a given width (B) to that of a single isolated footing having the same width. The maximum value of (?) occurs at spaced between S/B = 0.5 to 1.0. The results have been compared with those available in the literature.INTRODUCTIONEvaluating the ultimate bearing capacity of rock masses is essential for important projects like dams and bridges. Closely spaced footings may occur on rock masses in the form of pier foundation and grillage footing. Close spacing lead to permit higher loads than can be bore by similar isolated footings. The ultimate bearing capacity of two interfering strip footings resting on cohesionless soil have been studied theoretically (Kumar, & Gosh, 2007; Kumar, & Kouzer, 2008; Stuart, 1962). Results revealed when two strip footings approached closely enough, failure zones affect each other and ultimate bearing capacity significantly increased."

Jan 1, 2015

By Z. Zhong, Y. J. Hu, D. Elsworth

"A standard triaxial apparatus was set up to perform sliding tests. Slide-hold-slide (SHS) tests, with hold times from 10 to 3000s and at invariant effective confining pressures of 1MPa, incremented to 3MPa and then 5MPa, were conducted on both dry and wet split limestone samples to study the evolution of fracture friction under holding and sliding processes. Limestone fracture shows time-dependent behaviors in SHS tests, friction drops (creep) gradually during hold periods, and recovers (healing) after re-slide. Frictional healing and creep increment are proportional with hold times, while are inversely proportional with effective confining pressures. Moreover, the wet sample displays heavier healing than the dry one, whereas creep increment of the wet sample is lighter than the dry one. We conclude that the evolution of limestone fracture friction is significantly controlled by mechanisms of fluid-rock interactions.INTRODUCTIONThe evolution of the mechanical properties of fractures and faults exerts a critical influence on the behavior of fault zones and on the earthquake cycle. In addition to natural processes, this behavior has broad implications in induced seismicity and influences oil and gas production, the sequestration of carbon dioxide and the disposal of nuclear wastes.Fault friction is typically measured by slide-hold-slide experiments, where fault gouge is deformed at low velocities (<0.1 mms-1) and over small shear offsets (<30 mm) (Dieterich, 1979, 1981; Mair et al., 1999; Marone, 1998, 2004) or alternatively with rotary-shear devices, that enable higher slip velocities over very large shear offsets (Hirose & Shimamoto, 2005; Mizoguchi et al., 2006). Typical experiments (Dieterich, 1972; Marone, 1998; Olsen et al., 1998; Bos & Spiers, 2002; Tenthorey et al., 2003) show significant creep during the holding period and frictional healing (strength gain) upon reloading. Fault creep and healing are often time-dependent with longer hold times typically resulting in greater magnitudes of creep and in strength gains (Tenthorey et al., 2003; Yasuhara et al., 2005; Carpenter et al., 2012). Frictional healing may arise from growth of grain contacts (potentially induced by pressure solution) (Rabinowicz, 1951; Dieterich & Kilgore, 1994; Yasuhara et al., 2005), strengthening of the contacts (correlates with cementation) (Hickman & Evans, 1992; Beeler et al., 1994; Karner et al., 1997; Olsen et al., 1998; Muhuri et al., 2003; Tenthorey et al., 2003; Li et al., 2011) or via other changes in state including changes in porosity and rearrangement of force chains. Experimental evidence (Dieterich, 1979, 1981; Johnson, 1981; Marone & Scholz, 1988; Marone, 1998; Saffer & Marone, 2003; Moore & Lockner, 2007; Ikari et al., 2007; Ikari et al., 2011; Carpenter et al., 2012) quantifies both the mode and magnitude of second-order changes in the velocity-dependent (including velocity- strengthening and weakening) evolution of frictional strength."

Jan 1, 2015

By Oliver Hall

WITH the friendly consent both of the Institution of Mining and Metallurgy, for whom this paper was written, and of the author, we had the pleasure of publishing Mr. Oliver Hall&apos;s paper on Mining at Noranda in our issue of last March and of having Mr. Hall present it at the Montreal Meeting. In the following pages we now report the discussion elicited by the paper at a meeting of the Institution in London on March 18th. The report is taken from the April, 1937, issue of the Bulletin of the Institution, to whom we again tender our thanks. THE PRESIDENT (MR. ROBERT ANNAN) said that this paper was, by arrangement with the Institution and the author, also being published by the Canadian Institute of Mining and Metallurgy for approximately simultaneous discussion. He was sorry that Mr. Oliver Hall could not be present to introduce it in person, for he was sure that the author would have had many more details to give about this most interesting mine. The paper contained a very useful account of mining operations, and personally he had been pleased to see the tri-dimensional projections of the orebody in Figs. 3 and S. It was a good illustration o the value of that method in presenting the form of an orebody such as this. While he had no desire to go into technical details, he wished to call attention to a remark in Mr. Hall&apos;s introduction, in dealing with the history of the mine and the principles on which it was run. The author had given an account of the early difficulties in solving geological problems, and later of the economic difficulties of seeing this mine through a period of intense depression in metal prices. He stated that it was clear that, to maintain income, tonnage must be increased, and, to maintain profits, costs must be decreased. It would be observed that there was no question of increasing the grade of ore. Then the author went on to say: &apos;Having set the house in order in the years of adversity, the higher price for gold is being used to mine to still lower limits and lengthen the life of the enterprise and the welfare of those dependent on it&apos;.

Jan 1, 1937

By Jochen Petersen

This paper gives an overview of the various strands of postgraduate and undergraduate training offered in the Department of Chemical Engineering at UCT. Since 2003 the Department is offering a formal postgraduate MSc programme in hydrometallurgical engineering aimed especially at graduate work-based engineers, with 5 weeks of intensive course work plus a research dissertation on a work-related project. This programme has now run 5 times over the years and produced some 20 degrees. The paper reflects on the experiences with running the course, especially the difficulties experienced with supervising industry-based external students. Furthermore, through the Department a graduate training program is offered for all junior metallurgists at a major South African minerals company. This 2-year program, which is currently on its 12th cohort, offers 1 or 2 week intensive blocks of course work alternating with longer stints where the candidates are based at various operations. Although primarily focussed on minerals processing, it has a significant element of hydrometallurgy in it and in recent years an advanced hydrometallurgy stream has been introduced. The paper reflects on the development of the program over the years, the benefits it has provided to the company as well as some of the challenges that remain. Finally the paper gives an overview of hydrometallurgy related undergraduate and research-only postgraduate MSc and PhD projects at the university. Some emphasis is placed on the recently launched South African Minerals and Metals Research Initiative (SAMMRI), a joint government-industry programme to support university-based research in the area of applied metallurgy.

Jan 1, 2014

By G. M. Behrend

"AbstractMeasurement and control systems in minerals processing plants are usually well thought out and designed. The criteria and design parameters have been interpreted correctly.However, these systems often fail to perform satisfactorily or break down altogether as a result of in-plant conditions which are unpredictable and over which the instrument systems designer has no direct control. The foresight necessary to anticipate the problems and allow for them in the systems design can only be generated by experience.This paper lists the most common of these problems and offers practical methods for their solution. It then follows with an analysis of instrument installation practices and comments on special points that need watching.Finally, instrument maintenance is discussed with a view to achieving good maintenance at the best possible economy.Good MeasurementGeneralTHE MINES and mineral processing plants of the nineteen seventies, after decades of sensible caution, have now committed themselves to extensive automatic control. X-ray analyzers are freely specified. Sample acquisition systems are efficient and automated, computers are reliable and relatively cheap, and computer control systems in conjunction with the new analyzers are operating in a good many plants and are proving to be profitable.The sight of shift foremen and floor operators assembled in front of a TV-tube and taking a computer data display as gospel truth is quite common now, and yet was quite unthinkable only ten years ago."

Jan 1, 1977

By K. J. Palmer, D. A. Silva

"Evaluating resources and reserves requires the reliable modelling of geological domains and their grades. “Multiple point statistics” simulation is a relatively new geostatistical method to generate complex, high-resolution geological models by extracting high-order spatial relations from training images. A method based on combining multiple training images is developed to obtain the correct amount of large-scale continuity and short-scale variability. A calibration process matches the geological spatial variability between the final realizations and the drillhole dataset. A case study with data from the Red Dog mine, Alaska, United States, shows an appropriate reproduction of short-scale variability along boundaries between geological units.RÉSUMÉ L’évaluation des ressources et des réserves exige une modélisation fiable des domaines géologiques et de leur teneur. La simulation par « statistique multipoint » est une méthode géostatistique relativement nouvelle pour générer des modèles géologiques complexes à haute résolution par l’extraction de relations spatiales d’ordre supérieur à partir d’images d’entraînement. Une méthode basée sur la combinaison de multiples images d’entraînement est développée afin d’obtenir la bonne quantité de continuité à grande échelle et de variabilité à petite échelle. Un processus d’étalonnage fait correspondre la variabilité géologique spatiale entre les réalisations finales et l’ensemble des données de forage. Une étude de cas avec des données de la mine Red Dog, Alaska, États-Unis, montre une reproduction adéquate de la variabilité à petite échelle le long des limites entre les unités géologiques."

Jan 1, 2015

By A. G. Ballachey

Introduction This paper will describe the mining plant and underground operations at Quemont. Details of geology and milling are beyond its scope. Papers on these subjects will be prepared and presented separately. A detailed account of the exploration and development, 1944 to 1947, has been given by W. L. Brown (1). Location The mining concessions of Quemont Mining Corporation, Limited, are in Rouyn township, Rouyn-Noranda county, northwestern Quebec. These concessions total about 640 acres in area. They lie within the limits of the City of Noranda, contiguous to, and directly north of, the Horne mine of Noranda Mines, Limited. A large area in the southern part of the property is covered by the north arm of Osisko lake. Production The present operating rate is about 2,100 tons per day. Three flotation concentrates are produced: copper, containing a large proportion of the gold and silver in the ore; zinc; and pyrite, which carries an appreciable additional proportion of gold. The copper and zinc concentrates are shipped to smelters as produced. The pyrite concentrate is cyanided to recover additional gold, after which it is filtered, dried, and shipped for the manufacture of sulphuric acid. The principal revenue metals are copper, gold, and zinc. Silver and pyrite are important by-products.

Jan 1, 1952

By R. N. Chakravorty

Environmental monitoring plays a key role in coal mine safety. In recent years, significant advances have been made in the development of systems suitable for monitoring air in underground coal mines. Because of intensive mining and large capital outlay, the need for higher productivity consistent with safety is well recognized and it appears that environmental monitoring may help achieve this objective. This paper reviews the state-of- the-art in the monitoring technology with particular reference to hazardous gas detection in underground coal mines. The preliminary results obtained from ongoing studies, with regard to continuous monitoring of methane and carbon monoxide in mine air in some of the operations in Western Canada, are discussed. The inadequacies of the methods using spot samples are examined and the need to supplement the present practice with continuous monitoring systems is emphasized.

Jan 1, 1979

By L. K. Smith, C. R. May, K. R. Schrag, H. Buchwald

"New contracts for 65 million long tons of coking coal valued at over $900 million, over the next 15 years, herald the rebirth of Alberta's coal industry. The industry is optimistic that export orders may reach 20 million tons per annum by the mid-1970's. Coal will be extracted from underground and surface mines and it is expected that the total labour force will double from the present 1,200 men within the next two years. Ali the health hazards associated with coal mining are likely to be encountered and it will be incombent on the Provincial Department of Health to specify the standards which relate to health and environment where no such standards have previously existed. This paper examines some of the problems which are being encountered in setting up an environmental health program and reviews the practicability of environmental monitoring methods, with special reference to respirable dust."

Jan 1, 1969

By Tyler Roberts

New Afton mine is an 11,000 tonne per day block caving operation, located 8 km west of the city of Kamloops, British Columbia. Due to the nature of block caving and the weak rock mass at New Afton, the mine has faced and overcome many blasting challenges during its ramp-up to commercial production. As New Afton Mine continues to grow the demand for drill and blast precision has continued to grow as well; any misstep incurs delays in achieving full production capacity. The block cave mining method used at New Afton employs single-shot draw-bells, fired with very little void and blind undercutting, allowing little margin for error. New Afton has made continuous improvements to its blasting strategy by reacting quickly to real-time problems and employing sustainable, repeatable solutions to overcome its unique blasting requirements. Examples of these solutions include: increasing blast hole diameter, casing production drill holes, developing pre-loading procedures and developing strategies for remotely blasting under-broken remnants in both draw-bells and undercutting. Increasing the blast hole diameter has alleviated initial problems with hole plugging in the highly jointed rock mass at New Afton. This has reduced drill-cleaning time significantly and enabled New Afton to meet blasting targets. PVC hole casing was trialed when blasting in extremely fractured ground, where drill holes continually plugged. The casing allowed the drill holes to remain open long enough to load and blast. Calculations were carried out in order to achieve the same explosive energy in the cased holes as a typical blast. Results were generally positive, but more testing is required. Production flexibility and scheduling reliability have been maintained at New Afton by developing a pre-loading procedure for the production undercutting. In doing so, New Afton has been able to keep productivity high by having a flexible production schedule that is not reliant on a specific piece of equipment or production drive to remain productive; this flexibility is because the mucking of undercut material can occur at any stage of the drill/blast/muck cycle. New Afton has developed a strategy for blasting remnant under-break in its draw-bells and undercutting by remotely drilling holes near to the under-broken section and then loading the toes of these holes with emulsion, the remainder of the hole is then filled with grout. The holes are grouted in order to prevent damage to permanent pillars between draw-bells (where the majority of the recovery holes need to be located). Several critical areas were recovered using this technique with little to no damage to the remaining permanent pillars. Innovative blasting solutions have allowed New Afton to overcome obstacles in order to become a producing operation. Moving forward, New Afton looks to continue its trend of innovative drilling and blasting techniques when faced with out of the ordinary situations.

Aug 1, 2013