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By Guadalupe Sanchez, Roel Cruz, Sergio Castro, Claudia Beltrán, Isabel Lázaro

The recovery of zinc in refineries is strongly affected by the formation of zinc ferrites during the roasting of zinc concentrates. To achieve the highest zinc recovery most of these plants operate under high acidity and high temperature conditions in their leaching circuits. However, under these conditions high iron dissolution occurs. For iron control the common practice is to precipitate it as jarosite, and calcine is normally used as neutralizing agent. This practice causes a significant loss of metal values associated with the calcine, such as zinc ferrites and silver insoluble phases. These metal values are carried by the jarosite into confined waste in many plants. In order to diminish such losses, it is necessary to use a neutralizing agent that could substitute the use of calcine. An alternative neutralizing could be the basic zinc sulfate (BZnS). This work presents the results of a laboratory analysis on the required conditions for the BZnS production from process streams of a zinc refinery plant. Neutralizing behavior of BZnS was evaluated in iron precipitation as jarosite, in order to establish the feasibility of replacing the calcine and decrease the loss of zinc and other metals values during the iron removing step of the hydrometallurgical circuit of the zinc refinery under study.

Jan 1, 2014

By E P. Graham

Orebodies occur in an infinite variety of grades, shapes and sizes, and take many millions of years to grow. When extraction starts there is only one possible end -the mine sooner or later will run out of ore and shut down. If the mineral industry is to supply the ever increasing demands of modern civilizations, more and more metals must be found and mined. This will require a never-ending search for ore, and the development of every economic body, large or small. To justify the mining of a small orebody, it first of all must pay its way. If the size of the burden imposed by the capital cost estimates is not carefully worked out, an otherwise promising situation could be killed. The very nature of mining, as a transient industry, re-leases a steady stream of good used equipment, and the trained personnel to install and operate it. All manner of plans and layouts, which can be utilized at a new property, are available. Working these and other economies into the estimates will sometimes make enough difference to give a prospect the green light.

Jan 1, 1964

By M. M. Williams

WESTERN CAN ADA'S coal industry has experienced a serious set-back since 1949, following a pattern well known to its counterpart in the United States. The loss in coal markets in Western Canada has been particularly severe as the discovery of large reserves of oil and natural gas and the subsequent construction of re-fineries and pipelines roughly coincided with the dieselization of both main railways. While the coal industry will have to face a further decline in markets of long standing, others with a large growth potential can be se-cured if present marketing methods are changed where needed and if fundamental and applied research programmes are actively pursued. The energy and chemical potential of Western Canada's coals will eventually find their place in the ever-growing needs of industry and electric power producers. Electric power generation would appear to offer the largest and most immediate market for coal. If the coal industry is to serve this market adequately and gain as much of it as possible, coal operators ? must have a good knowledge of certain characteristics -of the electric utility industry and its fuel requirements. This paper is prepared primarily to set out some of these characteristics, but also discusses other probable markets for coal.

Jan 1, 1958

By J. Stiksma, K. Buban, J. Oftsie, R. Kalanchey, S. Sadykov, E. McConaghy

The Kazakhmys zinc refinery in Balkhash, Kazakhstan, which employs the Dynatec Zinc Pressure Leach Process, officially launched autoclave operations on December 27, 2003. The Kazakhmys plant is the world's first greenfields zinc refinery based on Dynatec's two-stage pressure leach technology. Production of zinc was realized on February 9, 2004, when the first cathode was stripped. Currently the plant start-up is ongoing, with progression to two-stage zinc pressure leach operation and ramp-up to full design capacity continuing through 2004.

Jan 1, 2004

By A. R. Farkoosh

Al-Si based alloys have been recently used by automotive industry for highly stressed engine applications. Due to severe working conditions of the engine parts, existing alloys hardly endure high pressures at high temperatures. This necessitates alloy modifications to enhance the elevated temperature performance. In this study, the effects of trace nickel additions on the microstructural and mechanical properties of A356+0.5Cu alloy have been investigated at different aging conditions. Electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used to study the microstructural changes. Aging curves have been obtained by hardness measurement. It was seen that the presence of additional nickel introduced many complex intermetallic phases within the microstructure which led to improved high temperature mechanical and aging response.

Jan 1, 2011

By Paul W. Kingston

In New Brunswick, during the 1970's, rocks of the Lower Carboniferous Windsor Group in the Moncton Basin of the Fundy Epieugeosyncline have been the target of intense exploration and drilling programs. Sylvinite ore was discovered in three structural basins of the Moncton Basin near Sussex through a drilling program sponsored jointly by the Federal Department of Regional Economic Expansion and the New Brunswick Department of Natural Resources. In 1973, exploration and development rights to the western end of the Moncton Basin were awarded to the Potash Company of America. One high-grade sylvinite unit, varying between 15 and 70feet in true thickness, with a strike length in excess of 5 miles, is located near the stratigraphic top of the assymetric, semi-diapiric, locally overturned anticline. Late in 1975, exploration and development rights to the Marchbank Syncline were awarded to International Minerals and Chemical Corporation (Canada) Limited. To date, a stratigraphic evaporite sequence, forming the semi-diapiric core of the syncline, has been shown to contain one major high-grade sylvinite unit averaging 70 feet in true thickness over a strike length in excess of 2 miles. Both properties appear to have potential considerably in excess of that revealed by the exploratory drilling, and both, because of numerous mineralogical, structural and stratigraphic similarities, are thought to be depositionally contemporaneous. Both potash deposits lie within 50 miles of the Saint John all-weather deepwater port, thus affording easy access to eastern and mid-western U.S. markets. Further opportunities for potash exploration in New Brunswick are considered excellent, as there are large untested areas with favourable geology and known potassium water anomalies and negative gravity anomalies occurring in the Moncton and Cumberland basins, and in the Central Basin of New Brunswick.

Jan 1, 1979

By T. A. Grammatikopoulos, B. Vasily, A. H. Clark

"The St. Lawrence deposit is a large wollastonite skarn (ca. 9 Mt @ 41.3% wollastonite) adjoining the gabbroic-to-syenitic Leo Lake pluton in the granulite facies Frontenac Terrane of the Grenvillian Central Metasedimentary Belt. It occurs within a horseshoeshaped horizon of quartzite, open to the east. The skarn extends over 1.2 km2, and comprises wollastonite-dominant, wollastonite-clinopyroxene, and diverse quartz-feldspar-sulphide (-titanite) layers, interbanded with, and strongly folded within, the quartzite. As in the world-class wollastonite deposits of the Willsboro district, New York, no carbonate protolith is preserved, and calcite is a negligible constituent of the mineralized zones. Wollastonite development is nonetheless ascribed to metasomatism of a metacarbonate unit by magmatogene, silica-rich, CO2-poor (XCO2 < 0.05) fluids, at P = 350 MPa and ca. 560°C, or, alternatively, 550 MPa and ca. 630°C.Several high-grade zones, averaging >40% but locally exceeding 80%, of translucent, white, tabular wollastonite grains, with lengths of 0.2 cm to 5 cm, have been delimited by drilling. Preliminary beneficiation studies yield high aspect-ratio and high-purity (low Fe and Mn) concentrates.St. Lawrence compares favourably to other known prospects and operating wollastonite deposits: having good chemical and physical properties, low iron content, and high aspect ratios (>20:1). In addition, the deposit has a favourable size and location, and will benefit from a low Canadian dollar. Canada currently has no wollastonite production."

Jan 1, 2003

By J. A. Vonhof, R. O. van Everdingen

Since 1949, a total of 59 disposal wells have been installed in Canada to inject liquid wastes from refineries, mining operations and chemical plants into subsurface formations at an ever-increasing rate. Well depths range from around 600 feet to almost 5,500 feet; injection rates range from 0.5 (U.S.) gpm to more than 1,000 gpm for individual wells; wellhead injection pressures range from a slight vacuum to over 500 psi. Apart from strictly technical considerations of well design, the geological, hydrodynamic and hydrochemical conditions at the disposal site have a strong bearing on the safety and success of such operations. Prevailing hydrogeological conditions in large portions of the country do not allow safe subsurface disposal.

Jan 1, 1973

By M. R. Henzinger, W. Schubert

"The quality of the backfill applied at a shield driven tunnel is of significant importance failure of the lining. The used material also affects the interplay between support and excavation behaviour.In this research the state of the actual bedding situation is investigated by an analytical approach, laboratory tests and numerical simulations. The numerical simulation using continuum methods have shown shortcomings. These shortcomings regarding the instability of large strain simulations restrict the possibility to reproduce the relocation of the backfilling material. The performed scaled model tests have shown that the regripping process of a double shielded tunnel boring machine affects the soil failure within the gap. With the analytical results the influence of the wall friction can be predicted. Therefore the angle of the failure surface can be determined. The results have shown that the wall friction significantly increases the failure angle. INTRODUCTIONFor tunnel boring machines (TBM) with single (SM) or double (DSM) shield, precast liningsegments are used as rock support. These segmental linings are installed within the protection of the TBM shield. In order to reduce the friction while advancing, the shield diameter is smaller than the diameter of the cutter head and therefore also smaller than the excavation boundary. The difference depends on the expected radial convergences. Since the lining segments are mounted within the shield the steering gap between the shield and the excavation boundary increases and is hereinafter called annular gap.In the process of tunneling in hard rock, the annular gap is usually filled with fine grained and closely graded gravel, termed as pea gravel. The backfilling process starts as soon as possible after the shield tail passes the lining. Due to the operational procedure within the working area of a TBM, a fully backfilled annular gap might not be established after every ring closure. This leads to an unfavorable distribution of the pea gravel leaving the segmental lining partially without bedding. Segmental linings can develop sufficient resistance only when properly bedded."

Jan 1, 2015

By Theophile Yameogo

Much has been said about the methodology of geomechanical design in underground excavations. However, the geological, hydrogeological and geotechnical complexities encountered at the production horizons in the Athabasca Basin commanded for a novel approach in the geomechanical assessment and design of underground openings. Rock mechanics engineers at Cameco McArthur River have been able to establish a practical methodology that goes beyond known conceptual approaches. In this paper, the author describes the original challenges and unique approach in the geomechanical assessment for drifts and chambers development. The example of the successful development of the 510-8225N Chamber will also be presented.

Aug 1, 2010

By H. A. Gorrell, S. R. L. Harding

"The potash beds in the Saskatchewan portion of the Williston Basin occur in the upper portion of the Prairie Evaporite formation of the Devonian Elk Point Group. They represent the late stage of a major evaporitic cycle. Two other evaporitic cycles are known in overlying beds, but these apparently never reached the stage of potash salt deposition. The basin in which salt deposition took place extended from the northwestern corner of Alberta southeastward across Saskatchewan into Manitoba, North Dakota and Montana. Deposition of potash salts was apparently restricted to the southeastern portion of the evaporite basin. On a regional basis, five major stratigraphie divisions of the potash-bearing strata have been made. Locally, several of these units may be divided into correlatable sub-units. The potash-bearing strata are separated and overlain by predominantly halite layers of varying thickness. Cross sections show the regional correlation of the potash-rich zones, and maps show the present distribution of the individual potash-bearing zones and the areas of richer development for each zone. The maps tend to substantiate the interpretation of considerable subsurface solution of salt and potash beds."

Jan 1, 1967

Mine Evaluation Engineering , Operational and Social evaluation. Focus is on what opportunities are available. Social ??History ??Past Management Practices ??Community / Available labor force Mining Method / Equipment ??Competent rock ?little support required, no backfill ??Shallow mining ?ramp mining, no shafts or hoisting ??Large scale mining potential ??Simple rock breaking and crushing on surfaceMill Process ??Straightforward gold liberation process Create a Plan / Create a Team Following the feasibility 44-101. Key people were hired and a full operational Business Plan was developed. Focus is on how to get the job done. ??Scoping Study / Pre-Feasibility / Feasibility ??Operational Business Plan ??Hire key people ??Purchase key equipment

May 1, 2006

By R. M. Beauchamp

Base metal processing operations often treat process tailings and acid mine drainage using a high density sludge (HDS) water treatment process. Lime is used in this process, which reacts with existing sulfates to form gypsum. When a recycle stream is incorporated in the process, gypsum levels in recirculating water may build up and cause high levels of gypsum supersaturation. Precipitation of gypsum from the supersaturated process water causes many problems. It is speculated that gypsum may precipitate on sulfide minerals and silica gangues in the flotation circuit, resulting in decreased selectivity and recovery. An understanding of the determinants and nature of precipitation may provide solutions to mitigate the formation of precipitates and improve flotation performance. This study showed that both sphalerite and silica exhibited gypsum- or calcium carbonate-like behavior in the respective supersaturated solutions, indicative of a coating of calcium species on the mineral particle surfaces. The addition of copper sulfate and/or potassium xanthate had little effect on the precipitation of gypsum or calcium carbonate on the mineral particles. Sodium carbonate is encouraging as a method to minimize calcium species interactions on sphalerite/silica surfaces.

Jan 1, 2006

By R. B. Kaunda

One fundamental requirement for surface and underground rock engineering is the ability to characterise the rock mass. An accurate characterisation of the rock mass allows rock engineers to optimize designs safely and economically. A number of classification systems have been developed in the past 50 years to help characterise rock masses such as RMR, Q system, Rmi, and several others. The challenge in developing rock characterisation schemes is often practicality, i.e. creating systems with relatively simple inputs for the everyday practitioner. A second challenge is the degree of subjectivity often inherent in commonly used classification systems. These challenges are especially exacerbated in weak rock or densely jointed rock masses. This paper introduces a new approach to characterise densely jointed rock mass using artificial neural networks and principal component analysis, based on principles commonly used in the geotechnical engineering of rock fills and waste rock dumps. Thirteen input parameters are dimensionally compressed using principal component analysis. Using a global database with more than 100 case histories, an artificial neural network is developed to conduct the rock mass characterisation. The advantage of this approach is less subjectivity as commonly used engineering (quantitative) terms are put to use. A further advantage is that given that the method is site-data dependent, it allows for ‘fine tuning’ of the model for a specific site.

Jan 1, 2015

By C Jincheng, L. Liang, L. Wenjun

"Considering overgrinding in a grinding process, the grinding characteristics of comminuted hematite products using a HPGR and a conventional CC were comparatively studied. The major properties including particle size, grinding kinetics and grinding technical efficiency (Et) were investigated. Individual size distributions (ISDs) of -2.0mm in a HPGR product showed a more significant “double-peak” characteristic than a CC product. As a result, HPGR products were finer and had a wider full-size distribution because of the greater proportion of fines. The parameters m and zi in m-th order grinding kinetics were analyzed by the partial-derivative method and the critical time tc(tc = exp (1/ zi)) was obtained. zi mainly affected the breakage rate when t < tc; otherwise, m mainly affected the breakage rate. In these tests, tc was considerably higher than the grinding times, and HPGR products yielded a higher zi-value than the CC product for the same sieve size. This indicated that HPGR products had a higher breakage rate and needed a shorter grinding time for a certain grinding fineness. Et was calculated by simulating the size distributions of batch grinding products. HPGR products gave a lower Et at a decreasing rate than the CC products for -2.0 mm feed and -0.5mm feed, and then showed a slightly higher Et for -2.0+0.5 mm feed. This indicated that overginding in HPGR full-size products was more serious under the condition of coarse grinding, whereas the efficiency was higher and overgrinding weakened significantly in HPGR coarse products because of screening-out fines. Based on the above research, a new process of “ultra-crushing in HPGR – classified grinding” was advanced, reducing ores tonnage into first stage ball mill significantly, improving grinding efficient and weakening overgrinding in the whole grinding process.INTRODUCTIONIn mineral processing, comminution accounts for a substantial portion (approximately 60~70%) of the energy consumed in plants. As an ultra-fine crushing equipment,the application of the HPGR for industrial comminution has been paid close attention because of its low specific energy, low steel consumption, high capacity and high ratio of reduction, among others (Schonert, 1998; Norgate & Weller, 1994; Fuerstenau & Kapur, 1995). HPGRs comprise two counter-rotating rolls that draw feed material into the roll gap. One roll is fixed to the mainframe, while the other movable roll is mounted on slides and positioned by hydraulic rams. The specific pressing force (SPF) (i.e., total force divided by projected roller area) is typically in the range of 3~9 N/mm2 depending on the application, while pressures of up to 1000 N/mm2 have been measured within the operating gap (Maxton , Morley, & Bearman , 2003)."

Jan 1, 2016

By Philippe Monier, Frank C. Basham

"This paper outlines the scope and applications of &apos;COALMOD&apos;, the British Columbia Ministry of Energy, Mines and Petroleum Resources&apos; computerized financial simulation model for coal mining developments. After a description of the computer system and language of implementation, the logic and scope of current model sub-routines are presented. This is followed by a presentation of examples on the current applications of the model to public policy evaluation, including benefit-cost analysis, fiscal analysis and evaluation of the effects of public infrastructure investments made in support of mining projects.IntroductionThis presentation has been developed in response to a number of requests from coal mining companies and various public agencies who have indicated interest in understanding our application of contemporary analytical techniques to public policy in the coal sector. In particular, the subject of this paper is an explanation of COALMOD. a mnemonic given to a computerized, mine-specific, financial simulation model which is assisting the Government of British Columbia in evaluations of new coal projects, assessment of public sector investments made in support of these projects and. more generally, measurement of the financial effects of current or proposed government policies, and factors outside immediate government control such as coal prices and transportation costs."

Jan 1, 1981

By David G. Meadows

During the last decade Antofagasta Minerals? Los Pelambres Mine has dramatically increased its ore throughput following the fast initial phase ramp up through a series of planned incremental expansions. The original 85,000 mtpd, two SAG line plant was commissioned in 1999 and rapidly exceeded nameplate tonnage in only a few months. Following this, the inclusion of a pebble crushing circuit resulted in throughputs in excess of 114,000 mtpd and a recent, final third line SAG and ball mill addition have taken the plant to over 175,000 mtpd even with increasing ore hardness and changing ore feed characteristics. The progressive changes are described in this paper together with how the technical challenges have been met.

Jan 1, 2012

By E. L. Warburton

Before entering into a discussion of wet washing, it will be advisable to consider the various phases and conditions sur- rounding the problem of cleaning coal from the Corbin mines. Corbin is located in the south-east part of British Columbia in the Crowsnest Pass district, about 35 miles north of the International boundary and about three miles west of the Flat-head Range of the Rocky Mountains. It is reached by a rail-way, about thirteen miles long, from McGillivray, B.C., a point on the Crowsnest branch of the Canadian Pacific rail-way, owned and operated by the Eastern British Columbia Railway Company, a subsidiary company of Corbin Coals, Limited. The coal is assumed to occur here, as principally elsewhere in the Rockies, in the Kootenai series of the Lower Cretaceous, but owing to the disturbed condition of the surrounding country and, therefore, the magnitude of the geological study involved, this has never been definitely worked out. The coal is of the usual Crowsnest high-grade steam-coal, containing from 9 to 12 per cent. of ash, but appears to have 4 to 5 per cent. less volatile combustible matter than other coals being mined in this district, a representative analysis being about as follows:

Jan 1, 1924

By Ron Hatch, M. K. Witte

"INTRODUCTIONThe proper selection of carbon for a gold carbon in pulp (CIP) circuit involves careful evaluation of several physical, chemical and economic factors. A series of evaluations are required to maximize gold recovery at the lowest capital and operating costs, whether the carbon is selected for an existing gold mill circuit or a new mill under design.Although evaluation may proceed through various stages, it is the intent of this paper to outline some of the preliminary testwork that should be carried out to screen potential carbons for a particular application.An examination of the specification sheets supplied by the various carbon manufacturers may indicate some desirable properties on which to make cursory selection. This exercise by itself will not provide the basic data needed for selecting the best carbon for a particular ore pulp and metallurgical circuit. The necessity of further metallurgical evaluation is indicated by the fact that different carbons perform differently depending on the physical and chemical nature of the leach pulp. In the case of an existing mill, actual leach slurries using mill water are available and should be used for testwork. In the case of new mills, leach pulps must be prepared to simulate the proposed circuit.Five coconut shell activated carbons were obtained from various suppliers, all reported to be 6 x 16 mesh carbons recommended for CIP circuits. A metallurgical evaluation was made utilizing two leach pulps with significantly different characteristics. This paper describes the test procedures utilized and the results obtained from the testwork."

Jan 1, 1985

By James F. Archibald

In historic mining practice, typical thin liner support systems have been considered to comprise non-reinforced or mesh-reinforced shocrete linings. In the early 1990?s, development of alternate forms of liner systems was initiated in Canada which is now undergoing significant international growth in countries which sustain major mining activity. Now internationally designated as thin, spray-on liner systems, a wide spectrum of liner materials, ranging from liquid/liquid to liquid/solid component combinations, has become commercially available. This innovative family of products is characteristically identified as being rapidly deployable, capable of creating ultra-fast setting coverage over rock surfaces, and able to develop tenacious adhesion and pull strength capacities for resisting rock falls and movements. This paper presents a summary of current liner developments and use in principal mining districts world wide. Additionally, a database of material properties for principal product types used in mining and a review of common quality control testing procedures under development are provided. Such information is based upon recent Canadian and international efforts being taken to assess and develop user standards for the implementation of thin, spray-on liners as rock support in mines. This work is intended to continue for a period of years, with the eventual goal being to establish support and installation guidelines for mines based on quantifiable laboratory and field research.

May 1, 2002