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By Yin Wang, Lin Li, Zhongwei Bi, Like Wei, Wen Li, Shaogang Li, Bin Zhang, Hongjie Li

Presently,Many long-wall fully-mechanized faces in shallow depth coal seams are below room and pillar goaf in Shendong mining area. When the working face is advanced out of concentrated coal pillar in upper room and pillar goaf, strong strata behaviors often cause support crushing accident. Aiming at a support crushing accident which happened in Shigetai coal mine of Shenhua group in Shendong mining area, this paper analyses the stress transfer process while mining out of concentrated coal pillar by numerical simulation software FLAC3D. According to the feature, simplifying the roof of upper room and pillar goaf as supporting-beam structure explains mechanism of large area collapse in room and pillar goaf roof. Based on the feature of supporting-beam structure, deep-hole blasting concentrated coal pillar technology is proposed to control the strong strata behaviors in Shigetai coal mine. The blasting control effect is confirmed through characteristics of strata behaviors, growth circumstance of ground crack and multi-point extensometer monitoring results. By using control technology, Shigetai coal mine has been successfully avoided support crushing accident.

Jan 1, 2015

By A. A. Iranzadeh

The performance of a tunnel boring machine (TBM) depends on the efficiency of the cutters, which can be influenced by geological conditions and rock mass properties. In this study, a three-dimensional numerical model, based on a discrete element method, was used to evaluate the effects of joint orientation and its spacing on the fragmentation process by a TBM cutter. Several models were constructed to study the effects of variable orientation; these models incorporated different spacing, variable spacing, different orientations on the fragmentation process, and different sections of the block model. Three parameters, consisting of induced tensile stress, induced shear stress and maximum displacement, were calculated. The stress in each section that forms chips was considered as critical stress; critical joint spacing and orientation in each section were determined. Results show that the critical orientation was in the range of 45 to 60º, where there was a possibility to achieve the maximum penetration rate. The critical joint spacing was 200 mm and, by increasing joint spacing, the value of critical stress decreased significantly. Furthermore, joint orientation could influence more than joint spacing in the rock cutting process.

Jan 1, 2009

By M. Kowalczyk

The successful application of color sorting machines has established sensor-based sorting in the mineral industry in recent years and is considered today as a significant innovation in processing technology. However, we are only at the beginning of the (market) introduction. New sensor systems have been developed, which exploit material properties such as electrical conductivity, magnetization, molecular structure, thermal conductivity etc. This opens up new exciting pre-concentration and upgrading possibilities for many applications such as nickel, gold, copper and other ores as well as for industrial minerals, diamonds and other gemstones.

Jan 1, 2009

By John B. Phillips

The mine is entered by a central vertical shaft, strongly timbered, and containing two compartments-one for the passenger cage, the other for the large skips bringing the ore to the surface. A man-way, for emergencies, is also provided, parallel to the shaft. The cage is a single-deck steel box, carrying about thirty persons; by means of arrangements above and below, it can also hoist and lower materials needed in the workings. Levels are run at intervals of 100 feet. In special cases, where the ore conditions warrant, sub-levels are operated, such as those at 1,113 feet and 1,123 feet (Fig. 7), which are connected by winzes with the 11 th level. One of these was pushed for 40 feet, and then abandoned because it was unprofitable to take up ore of the grade encountered. The ore between levels is removed by stoping. The drifts follow the course of the veins as much as possible, with numerous cross-cuts. Winzes, raises, connections, etc., are blasted out where needed. The main drifts are at least 8 ft. high by about 9 ft. wide. All former narrow drifts had to be widened sorne time ago, by ruling of the Ontario Department of Mines, to lessen the danger of accidents with cars in the small passages. Accurate plans of the under-ground workings are kept in the office, and extensive surveying is always being done underground to keep the maps up to date, measure the cubical contents of stopes, and so forth. Timber is extensively used in the construction of supports and chutes, and in the sinking of the shaft. Steel and concrete are too expensive to compete with timber, which 1s abundant in such sections as have escaped forest tires.

Jan 1, 1926

By Mario Bureau

Need for a lab assembly reaching better and consistent static anchorage capacities

May 1, 2013

By B. Westin, G. Voicu, C. Daoust

Orogenic gold deposits represent a major class of deposits that are found in various rock types of various ages. Those deposits show a strong structural control that usually complicates their interpretation at the regional and deposit scales. The Rosebel Gold district located in Surinam (South America) is hosted in a Paleoproterozoic greenstone belt of the Guiana Shield, and has been recently classified as one of those orogenic gold deposits. The gold district comprises eight distinct deposits located along three different structural trends and within different rock types. The mineralization is undefonned and shows a strong structural control characteristic of orogenic gold deposits. All the deposits of the Rosebel Gold district have been subject to a detailed structural analysis that has led to the elaboration of a new structural model for the whole gold district, which is now differing considerably from the previous models. This characterization had direct implications at three different scales. 1- While the older models were considering some areas of the property as gold-barren, the new structural model has led to recent exploration campaigns which have revealed positive results. 2- At the deposit scale, the comprehension of the various vein systems and of the folding of the host rocks has helped the establishment of optimized drilling campaigns. 3- At the mining scale, the comprehension of the architecture of the veins helps for the elaboration of optimized mining method. This study thus shows that the structural analysis of orogenic gold deposits is critical, and should be a priority for exploration and production in any mine.

Jan 1, 2011

By S. Kelebek, E. Yalcin

This paper reports bulk flotation characteristics of a pyritic gold ore sample from the Barry District, Quebec using isopropyl and amyl xanthates. The ore sample was highly floatable with particles showing tendencies for self-aggregation that was most apparent in the first stage of flotation. A possible reason for this is discussed. The gold concentrate grade-recovery performance with respect to the particle size is presented for the rougher-scavengers as well as for the cleaners. The effects of copper sulphate as an activator, fuel oil and NaSH as a sulphidising agent are discussed along with the recovery by size behaviour.

Jan 1, 2011

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 James Kear, Romain Prioul, Robert G. Jeffrey, Andrew P. Bunger, Dimitry Chuprakov

"Unconventional gas and geothermal reservoirs are typically naturally fractured and therefore the challenging problem of hydraulic fracture (HF) growth through naturally fractured rocks is an important issue especially for the development of accurate predictive HF models. This paper presents results from laboratory experiments in which HFs have been created in both sandstone and crystalline (gabbronorite) rock specimens such that they impinge either orthogonally or at an oblique angle on an unbonded, machined frictional interface. Depending on the conditions of each experiment, the fractures either cross or are blunted at the interface. The growth behavior was ascertained for these experiments based on a synthesis of the injection pressure record, active ultrasound monitoring, and direct post-experiment inspection of fractured specimens. From these experiments we observe: 1) A contrast between direct crossing and crossing with an offset for orthogonal and oblique intersection, respectively, 2) Apparent independence of crossing/blunting behavior on the friction coefficient for orthogonal intersection, 3) Dependence of the stresses required to promote crossing on the intersection angle between the HF and NF, 4) Existence of cases in which the hydraulic fracture crosses but then essentially ceases propagation such that all fluid is diverted to the interface. INTRODUCTIONHydraulic fracturing is a vital technology used to increase the productivity of oil, gas, and geothermal wells. Predicting hydraulic fracture (HF) growth is, in turn, critical to design of hydraulic fractures that grow to the desired length, accept the desired amount of proppant, and remain contained in the reservoir without unwanted height growth into surrounding layers (e.g. Economides and Nolte, 2000). The importance of HF modeling has prompted 6 decades of research during which simulators have become more efficient, more accurate, and have addressed a growing range of complexities (see review of e.g. Adachi et al., 2007).One of these complexities is the interaction between HFs and mechanical discontinuities such as natural fractures (NFs). Efforts in this area have been mainly driven by development of unconventional (i.e. low permeability) oil and gas resources because essentially all viable low permeability reservoirs, including shale gas/oil reservoirs, are naturally fractured to some degree (King, 2010). One of the most important questions for developing effective HF stimulation strategies in these reservoirs is whether the hydraulic fracture(s) is/are expected to be single-stranded or whether interaction with the NFs will lead to network-like growth. The basic building block for numerical simulators that can address this question (such as Kresse et al., 2013 and Weng et al., 2014) is whether an HF that intersects an NF will cross the NF or whether its growth will be captured by the NF so that additional fluid injection pressurizes the NF but does not generate ongoing growth of a new HF. These scenarios, including subcategories such as crossing with an offset, have been recognized for several decades (Daneshy, 1974; Warpinski and Teufel, 1987, and as recently reviewed and expanded by Chuprakov et al., 2013)."

Jan 1, 2015

By J. Coffin, M. Muinonen, D. Fragomeni, R. Multani, C. Deredin

"Rejection of pyrrhotite from pentlandite is of critical importance to the economics of nickel concentrate production and the main goal of the Strathcona milling operations. A joint team of XPS, Glencore Technology and Strathcona Mill personnel executed a comprehensive program of work to develop and implement strategies for increased Po rejection with focus on challenging ores containing high feed Po/Pn ratios (> 7) and significant hexagonal Po content (> 40% of total Po). This paper describes the team results including minerology, bench-scale flotation tests, and plant validation tests and modeling that have defined the path forward to improving the metallurgical performance and economics of the mill operation. Techniques to quantify hexagonal and monoclinic pyrrhotites were developed at XPS to assess the differences in their metallurgical behavior since their flotation responses are quite different. Mineralogical tools including QEMScan were extensively used to determine mineral liberation, associations, optimum grind size, and nickel deportment into pentlandite, pyrrhotite and non-sulphide gangue. Several reagents/strategies were evaluated during bench-scale flotation testing to significantly increase Po rejection. A significant shift in the Po-Pn selectivity and grade recovery curves was achieved using several strategies including the use of DETA and sodium metabisulfite, and regrind of the rougher concentrate and rougher cleaner/rougher tails.INTRODUCTION The Strathcona Mill is owned and operated by Glencore Nickel – Sudbury Integrated Nickel Operations and has been processing Ni-Cu ores from the Sudbury Basin since 1968 (valuable sulphides: pentlandite (Pn) – (Ni,Fe)9S8 and chalcopyrite (Cp) – CuFeS2). Currently Strathcona Mill receives ore mined from two main sources in the Sudbury area and produces two concentrate streams – a nickel-copper concentrate that is shipped to the Sudbury Smelter and a copper concentrate that is sent to the Fonderie Horne (Glencore Copper, Rouyn-Noranda). The general flowsheet currently used at Strathcona is displayed in Figure 1. It is highlighted by separate feed circuits for regular grade Ni ores and high grade copper ores. The copper circuit has a preflotation stage prior to a rougher-scavenger stage, a copper-nickel separation circuit, and a pyrrhotite (Po) rejection circuit."

Jan 1, 2018

By F J. Kelly

A chemical process, based on laboratory investigations, is proposed for the production of high-purity niobium oxide from a pyrochlore-perovsk1te flotation concentrate produced from ore obtained at the Oka, Quebec property of Columbium Mining Products Limited. The method developed included the decomposition and dissolution of the flotation concentrate with hot, concentrated sulphuric acid. The dissolved niobium was purified and concentrated by a solvent extraction step, using methyl isobutyl ketone as the extractant. The niobium was recovered from the extractant with ammonium fluoride solution from which niobium oxide was precipitated with ammonia. Finally, the filtered and washed precipitate was calcined. Ninety-six per cent of the niobium was recovered in a product analysing 99.9 per cent Nzo.. The reagent cost was in the range of $1.00 to $1.25 per pound of niobium recovered. Introduction OVER the past few years, Columbium Mining Products Limited has been engaged in the development of a niobium-bearing mineral deposit in the vicinity of Oka, Quebec. One phase of this program resulted in a flotation process capable of producing concentrates containing up to 50 per cent Nb205? Flotation pilot-plant

Jan 1, 1965

By M. M. O?Brien

THE SULLIVAN MINE The Sullivan mine of the Consolidated Mining and ? Smelting Company of Canada, Limited, is situated at Kimberley, B.C., nineteen miles from Cranbrook, a divisional point on the Crowsnest Pass branch of the Canadian Pacific railway. Production started on a small scale in 1900, and in 1914 the mine became the largest lead producer in Canada. In 1925 it was the largest single producer of lead and zinc in the world. Since operations commenced, 4,800,000 tons of ore have been produced from stopes and 170,000 tons from development. At the present time, ore is being mined at the rate of 1,100,000 tons per year, with a yield of about 200,000 lb. lead, 110,000 lb. zinc, and 4,000,000 oz. silver. The town of Kimberley is easily accessible by road as well as by rail. The altitude at Mark creek, a tributary of the St. Mary's river, is 3,700 feet. To th'e north of the creek, Sullivan hill rises to a height of 6,100 feet, and it is on the southern slope of this hill that the mine is located. Sullivan hill is in the Purcell range, which rises between the Rocky Mountain trench on the east and Kootenay lake on the west. It thus lies within what is commonly referred to as the East Kootenay district.

Jan 1, 1926

By Yujing Jiang, Xuezhen Wu, Bo Li, Tomomi Iura, Gang Wang

"Yielding bolt has been widely used for rock reinforcement in mining and civil engineering in high stress conditions. However, the interaction mechanism of yielding bolt and matrix mass is still not clear at present, and no analytical model is available to predict its reinforcement effect quantitatively. In this paper, the mainstream yielding rock bolts were reviewed firstly. After that, a coupling model is proposed to account for the interaction between yielding bolt and matrix mass. Based on the plane strain axial symmetry assumption and the incremental theory of plasticity, equilibrium equations and compatibility equations of matrix mass, and also the response of yielding rock bolt are deduced theoretically. The proposed method was programmed in Visual Basic development environment, and a semi-analytical solution for the coupling model is achieved. The reinforcement mechanism of yielding bolt in conventional tunnelling is clearly demonstrated through an illustrative case study. The reinforcement effect of yielding bolt is estimated quantitatively, and the distribution of axial force along the bolt is presented. In addition, the validity of proposed method is verified by numerical simulations. INTRODUCTIONHigh stress in surrounding rock mass can cause serious stability problems such as massive squeezing in soft rock and rock burst in hard rock. It is observed that many conventional rock bolts failed when experiencing large displacement, which implies that they are too stiff to sustain large deformation and dynamic conditions (Stillborg, 1994; Hoek et al., 1995). Yielding bolt, which can also be called energy-absorbing bolt, has been widely used for rock reinforcement in mining and civil engineering for these conditions (Neugebauer, E., 2008). This paper focuses on the static reinforcement effects of the yielding bolts with analytical method and numerical simulations."

Jan 1, 2015

By A. D. Burns, K. M. Nikolaisen

Electrolytic reduction followed by the addition of sulfuric acid and the application of heat can be used to selectively crystallize uranous sulfate from solution. This approach, when coupled with downstream thermal decomposition, forms the basis of a process for primary uranium recovery and purification where much of the sulfuric acid value can be recovered and recycled. In this process, a purified uranium (VI) leach solution is first electrolytically reduced to uranium (IV) in a membrane electrolysis cell. Sulfuric acid is then added to the solution which, in conjunction with the input of heat, causes the crystallization of uranous sulfate tetrahydrate. The precipitate is then dried and thermally decomposed to U3O8, which releases a mixture of high-purity SO2, SO3, oxygen, and water vapour. This gas can be recovered as sulfuric acid in an existing acid plant, processed through a new wet sulfuric acid process, or absorbed directly into the upstream electrolyte as a substitute for fresh acid in the crystallization step. This process has been shown to be practical, efficient, and cost-effective on the laboratory scale, and could be practiced on the industrial scale using commercially available equipment. This paper focuses on the thermal decomposition process and options for acid recovery.

Jan 1, 2020

By B. Panton, J. Carvalho, E. T. Brown

High-capacity, post-tensioned anchors have found wide-spread use in initial dam design and construction, and in the strengthening and rehabilitation of concrete dams to meet modern design and safety standards. Despite the advances that have been made in rock mechanics and rock engineering during the almost 80 years in which post-tensioned anchors have been used in dam engineering, some aspects of the rock engineering design of high-capacity rock anchors for dams have changed relatively little over the last 30 or 40 years. This applies, in particular, to the calculations usually carried out to establish the grouted embedment lengths required for deep, post-tensioned anchors. These calculations which involve a number of aleatory and epistemic uncertainties, usually make simplified assumptions about the distribution and values of rock-grout interface shear strengths, the shape of the volume of rock likely to be involved in uplift failure under the influence of a system of post-tensioned anchors, and the mechanism of that failure. The resulting designs are generally conservative. These aspects of the rock engineering design of large, post-tensioned rock anchors for dams could be improved by making greater use of modern, comprehensive, numerical analyses in conjunction with 3D models of the rock mass structure, realistic rock and rock mass properties, and the results of prototype anchor tests in the rock mass concerned.

Jan 1, 2015

By S. Ng, Peter Stapleton, Paul Mankowski, J. Spence, R. Siy

"Syncrude has developed a low energy extraction process for the recovery of bitumen from oil sand. This new process operates at a temperature of 25 °C, resulting in substantially lower energy costs and lower capital costs, especially for the thermal energy generation equipment. The process will be used in Syncrude’s Aurora Mine, which is scheduled for startup in mid 2000. The flowsheet for Low Energy Extraction includes hydraulic transport of oil sand slurry, and bitumen separation using collector and frother chemicals and air as process aids. A number of flow sheet innovations and optimizations have been included, resulting in the next generation of extraction technology. Experimental pilot plant results, engineering progress to date and areas of ongoing work will be discussed. SUMMARYThe Low Energy Extraction Process has been successfully developed for commercial implementation at Aurora. The 1996 100 tonne hour Field Pilot demonstrated that the bitumen recovery target could be met with an 11.1% grade oil sand. However, pilot plant bitumen recoveries for a lower grade oil sand were not acceptable. The subsequent flowsheet optimization study led to a new flowsheet for Low Energy Extraction, which includes a primary separation vessel, a flotation circuit for PSV middlings, and the use of middlings displacement in the PSV cone bottom with flotation underflow. A test program conducted in 1997 showed that the new flowsheet could significantly improve the bitumen recoveries for lower grade oil sands. Engineering work on process scale-up led to selection of a 30 meter diameter PSV, with a tangential feedwell. The successful development and commercialization of Low Energy Extraction for the Aurora Mine Project is a major enabling step in the Syncrude 21 program. The low energy requirements of this process allow Syncrude to develop the Aurora leases more cost effectively. The use of this process results in major capital cost savings, predominantly in the thermal energy infrastructure and also provides long term operating cost advantages for Syncrude."

Jan 1, 1999

By J. M. B. Scarborough

This paper deals with measures taken to maintain effective operation of heavy-duty equipment in open-pit mining. at Pine Point, N.W.T., during periods of extreme cold weather. The points covered include equipment modifications designed to improve cold-weather performance, effective lubrication of machinery that is vulnerable to extreme cold and operating procedures designed to prevent equipment damage.

Jan 1, 1966

By P. Mengé

The covering of a hydraulically filled goethite pond is discussed from a geotechnical point of view. The characteristics of the goethite were defined in order to allow a detailed study of the procedure for the construction of the cover on top of the soft material and a verification of the stability of the cover and side slopes after construction. These characteristics and the main results of the studies are given, as well as the experiences and observations made during the execution of the work. Finally, the monitoring plan, during and after construction, is also discussed and some results are given. The 'Design and Construct' contract form was used to allow the contractor to choose the optimum and most economical method to realize the closing of the pond, based on his experience with similar projects. The works were carried out between mid 2003 and the end of 2004. The paper will, amongst others, discuss the special method of working that had to be developed to allow the covering of the whole pond in a relatively short time period, without soil improvement methods such as vertical drains or stabilization by in situ treatment. Fill material was used to establish a platform on top of the soft material so that the cover liner and finishing layer could be installed on top of the fill layer. The 'floating roof' principle was used; subsidences were allowed to occur during the installation of the impermeable top liner and soil cover.

Jan 1, 2006

"The content of production reports has its origins in raw measurements taken in harsh production environments. The ensuing measurement/estimation errors always affect reproducibility such that, regardless of the fact that they are balanced through statistical data reconciliation, reported numbers are simply the most probable values of inferred probability distributions. This has important implications for how metal recoveries should be monitored and reported. Indeed, in a context where many process optimisation activities are based on small improvements in recovery, there should be no doubt that inadequate handling of measurement/estimation errors can easily exaggerate or mask actual changes in process performance. However, estimates of the reproducibility of reported metal recoveries are rarely reported to plant management. This situation persists despite the fact that a code compliant metal accounting system must inform management about business risks related to metal accounting. To this extent, this paper focuses on the continuous management of reproducibility level of metal recoveries in compliance with the best practices. Sensitivity analysis of primary and secondary metal accounting models is performed to show the resulting probability distributions for metal recoveries. Some guidelines are given for designing and managing metal accounting systems capable of achieving and sustaining predefined levels for the reproducibility of metal recoveries.INTRODUCTIONEach and every mineral processing plant produces daily, weekly and monthly production reports in which metal balances for payable and penalty elements are presented. While such production reports are usually consulted in offices, underlying raw measurements are taken in harsh production environments where mechanical vibrations, humidity, corrosion and dust, to name a few, disturb measurement procedures. It is thus no surprise that several authors (Francois-Bongarcon & Gy, 2002; Gaylard, Randolph, & Wortley, 2014; Holmes, 2010; Spangenberg & Minnitt, 2014) have reported pervasive issues related to mass/sampling measurements in the context of mineral processing."

Jan 1, 2016

By Richard K. Komarek, Antonios Zavaliangos, Roman T. Dec

Current industrial compacting and briquetting practices are largely based on trial-and¬error techniques. This paper introduces a two dimensional finite element model of compacting/briquetting process in the roller press. Compared with other modeling techniques used in the past, finite element method offers the most versatile approach because it incorporates adequate information about powder behavior, geometry and frictional conditions and offers predictions for the density distribution, velocity field, stress distribution, roll force, roll torque and other important process variables. More over, when the model includes elasticity, it offers predictions on the internal stress state in the briquet after its exit from the pressing zone. This enables to perform realistic computer experiments which are helpful for establishing the pressing system design, forming cavity geometry and process conditions necessary to produce compacted or briquetted product with the desired properties.

Jan 1, 2004