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By E. Thomson

This type of microscopic investigation, although still in its infancy, has already found practical applications in several different phases of mining activity. The study of the transparent minerals in rocks, by means of the ordinary petrographic microscope, has for long been a very useful supplement to observations in the field, but the opaque minerals, until recently, have had to rest content with a more or less superficial determination with the hand-lens or the blow-pipe. In a great many cases, particularly where the association of metallics has been somewhat complex, this has been entirely inadequate, and the determination of these opaque minerals under the micro- scope, has opened up a new field of scientific investigation that bids fair to surpass, in practical value at least, the micro-scopic determination of the rock-forming minerals. As the details of this kind of microscopy are possibly not entirely familiar to all mining men, it might be well to outline them very briefly before dealing with the practical directions in which this method may be applied. The ordinary petro-graphic microscope, with but one extra attachment, will serve for this work. A small reflecting device, called a vertical illuminator, is inserted immediately above the objective lens. This reflects the light down to the surface of the specimen and from here the light is directed up the middle of the microscope tube to the eye. As it is desirable that the maximum amount of reflection should be secured from the surface of the section, it is first polished and set in a position perpendicular to the vertical axis of the microscope.

Jan 1, 1924

By Thomas Kilpatrick

The liability created by building this railway is the great financial problem before the people of British Columbia at the present time. In dealing with the subject, I propose to divide it into three periods: The Past - The Present - and The Future. The Past The primary objects in building the railway were to provide an independent and direct route for the Grand Trunk Pacific railway into the city of Vancouver, and to open the central and north-eastern portion of the province.. This vast territory, almost one-half the entire area of British Columbia, has great wealth in fruit, agricultural, and grazing lands; timber, coal, water-power and minerals of all kinds, including some of the richest placer deposits in the world. Rivers and lakes teem with fish. Big game, including moose, elk, caribou, deer, grizzly and black bear, mountain goat and sheep, is plentiful and there is an abundance of small game and fur-bearing animals. In addition, its scenic attractions are unsurpassed in Canada. To develop these resources it was considered necessary to build a railway from south to north as a main artery of transportation and, if necessary, branch lines to carry heavy .shipments of coal or other commodities. Lighter freight may be handled by motor trucks from distant points to the railway.

Jan 1, 1925

By B. H. Sadagah

"Construction of mountain roads at north westerly Saudi Arabia is a difficult task in rugged terrains, where the rock masses are steep slopes, and full of geomorphological constraints.Werka descent lies at the north west region of Saudi Arabia. The Werka descent, constructed four years ago harmed due to rainstorm. The rock masses are metabasalt and metaryolite tuff rocks. The road is eight m-wide, surround by unsupported sharp manmade slope cuts, reaches up to 15 to 40 m height on both sides. Failures took place at both sides of the road, and blocked it. The road of almost 2 km long subjected to all modes of slope instability such as rockfalls, manmade slope failures and debris flows in the absence of the remedial measures. The very precipitous 40 m-high rock slope-cut along the road has no benches, backed by a natural slope of almost 80 m height. Both types of slopes suffer from rockfalls and slope failure’s incidents, frequently took place mainly in rainy seasons. The steep manmade rock slope cut is less than 1 m close to the road, with no ditches, form a potentially source area for rockfall’s hazards.Intensive geotechnical study includes utilization of the RMR and GSI rock masses classifications indicates that the rocks are fair to poor quality. The DIPS, RocFall, Swedge, RocTopple, RocPlane computer program, in addition to GIS and DEM image utilized to perform modeling and deterministic analysis, in order to suggest the mitigation measures for the natural and manmade slope cuts and rockfalls. The seismic coefficients of 0.1 to 0.4 taken into consideration in modeling processes. Input parameters to model the rockfalls and slope failure’s characteristics were studied such as GSI, block size; seeder points, locations of fallen blocks; slope angle, restitution coefficients, and slope roughness. The programs modeled the proposed location, height and energy of the rockfall barriers, collectors, and rock bolts. Two manmade slope cuts studied and modeled utilizing the integrated techniques were to eliminate the risk of slope failures and rockfalls through the construction of remedial measures, this is the study objectives."

Jan 1, 2015

By R. W. Lawrence, A. Bruynesteyn

"Pre-oxidation of refractory pyritic concentrates by biological leaching to enhance the recovery of gold and silver in cyan ideation has been investigated. The results of laboratory tests on three concentrates are presented. In all cases substantial increases in precious metal recoveries were obtained following the pre-treatment. For one concentrate, gold recovery of 81% was achieved following an 87% oxidation of pyrite, compared with 24% recovery by direct cyanidation of non-oxidized concentrate. Gold and silver recoveries from the other concentrates were increased from the range 60-78% to over 90% and from 80-86% to over 98% respectively. Operating parameters are discussed and methods of maintaining high oxidation rates are evaluated. Methods of employing this pre-oxidation technique in commercial practice are described.IntroductionMany of the gold and silver deposits now being developed contain precious metals finely disseminated in sulphide minerals such as pyrite. These ore s often present considerable resistance to metal recovery. The ease with which gold may be extracted is usually related to grain size and its manner of distribution within the host mineral. In many cases, a significant percentage of the gold may occur in submicroscopic form, or in solid solution with pyrite, so that even very fine grinding fail s to liberate the metal for recovery by cyanide leaching. Such ores are often termed refractory. Even in cases where liberation by fine grinding is practicable, high cyanide and lime consumption may be experienced due to the presence of specific sulphide minerals, and poor metal recovery may result.Pre-oxidation methods for refractory ore s and concentrates are commonly used to improve precious metal recoveries. Roasting, for example, as a pre-treatment to cyanidation, removes harmful constituents by oxidation or volatilization, and liberates gold from pyrite. In some cases, however, this method of pre-oxidation can result in poorer metal recovery, particularly of silver, due to fusion and the formation of clinker, and the formation of compounds which consume cyanide in the subsequent metal recovery stage. Difficulties in compliance with environmental pollution regulations may also be encountered."

Jan 1, 1983

By R. Scheepers

"Mineral deposits and prospects of the Pan African Saldanian orogenic belt in the southwestern Cape Province South Africa, are reviewed. Despite the entire absence of operating base or precious metal mines in the area, this study has established at least four metal associations that offer enticing exploration potential.The poly-phase deformed, low-grade metamorphosed volcano-sedimentary Malmesbury Group constitutes a complex, poorly understood supracrustal sequence that has been loosely subdivided into the Tygerberg, Swartland and Boland tectono-stratigraphic terranes by northwesterly trending fault zones. Syn- and post-tectonic granitoids of the Cape Granite Suite selectively intruded these terranes. Early S-types preferred the Tygerberg terrane whereas the later I-types dominate the remaining areas. Anorogenic A-type granites, however, occur in all three domains. Known metallization is directly or indirectly related to the intrusives, yet syngenetic deposits are conspicuously absent from the supracrustals. Four metal associations have been identified.• Cassiterite-wolframite (± Au, Cu, Mo, Fe-sulfides) in quartz and quartz/aplite veins hosted by tourmalinized and locally greissenized S-type granite. Similar exo-granitic veins occur in proximal metamorphites.• Juxtaposed disseminated, stockwork, breccia and vein style Cu-Mo-Fe-(Au)-sulfide mineralization hosted by mafic to intermediate intrusives of high K calc-alkaline, I-type affinity. • Cu-Mo-Au-sulfides hosted by hydraulic breccia pipes, stocks and veins occurring in anorogenic A-type alkali feldspar granites and amphibole quartz syenites.• Scheelite with minor Cu-Mo-sulfides and Au-associated with endo- and exo-skarns spatially related to I-type monzogranite, granite and alkali feldspar granite.The first three associations occur along the Yzerfontein-Helderberg-Zone, a 180 km lineament in the Tygerberg terrane, a zone exploited by syn-, late- and post-tectonic intrusives and their related mineralization. The fourth association is typical of the Boland terrane. The spatial and temporal relationships between the various metal associations is interpreted as the result of sequential intrusion of relative early high level S-type, followed by intermediate level I-type and finally anorogenic A-type granitoids during the evolution of a contracting continental margin arc and its irmer arc. This plate tectonic setting suggests subduction in an easterly direction underneath the Kalahari craton. The spatial configuration of the various terranes at the present erosional levels is the result of rifting and significant differential vertical displacement following cessation of subduction, a terminal tectonic event possibly synchronous with intrusion of the A-type granitoids.Near surface preserved roof zones and cupolas of both S- and I-type granitoids in the Tygerberg and Boland terranes, respectively, render these areas extremely prospective for Sn, W, Mo and Au mineralization. The presence of intermediate to mafic volcanics, a diversity of calcareous lithotypes and favorable plate tectonic setting of the Malmesbury Group suggest potential for the thus far elusive VMS, MVT and Sedex base metal and minor precious metal deposits."

Jan 1, 1994

By Malcolm Scoble

Process Technologies Suitable for Application Underground Design Criteria - coarse particle technologies - compact, robust, flexible - waste products suitable for use as backfill Process technologies identified: - Optical/conductivity sorting - Dense media separation - Coarse-particle flotation Process technologies supported by compact & efficient comminution stages Mineralogical evaluation to select process & estimate Performance Further Work U/G Plant Layout & Excavation Modelling Evaluate scenario at increasing depth Establish properties of waste as backfill Model impact of improved backfill quality Evaluate further case studies Evaluate further Environmental Health and Safety Issues Model impact of system development on inventory of national mineral reserves Conclusions Technologies exist for integrated underground mining and processing systems These technologies to be successfully integrated into underground mining system Positive economic and environmental benefits Technical issues to be resolved at depth System Development path identified

May 1, 2004

By N. R. Thornton

This paper discusses the rapid growth in the application of instrumentation for metallurgical process control. It covers such methods as ultrasonics, pulp density measurements, on-stream X-ray analysis and reagent control, as well as the expanding use of computer control and data acquisition.

Jan 1, 1971

By Arnold R. Miller

Overview ? Vehicle Projects LLC (prime contractor) and the Fuelcell Propulsion Institute have developed the world?s first fuelcell locomotive. ? Principal applications are underground mining and tunneling. ? Because fuelcell vehicles solve the problem of underground emissions, mining is expected to be their first commercially viable market. ? The first year of a three-year project to develop a fuelcell mine loader is funded and underway.

May 1, 2002

By J. Kang

Large-scale land reclamation has been undertaken in Singapore since the 1960s. In the early years, the fill materials excavated from the hills. In recent years, sea sand is the main source of the fill materials. The contractors used to import the sea sand from the neighbouring countries such as Indonesia. However, in early 2000, the sea sand import from Indonesia and Malaysia was banned. Cambodia, Myanmar, and Philippine therefore became the alternative sources for sea sand. Distance between the jobsite and these countries is over 1,200 km, and transporting sea sand from these areas became a critical issue that could affect the contractor?s performance. Figuring out the right combination of transportation means for a longdistance sand transportation would be challenging because of uncertain situations. We developed a stochastic simulation model, using ARENA, to figure out the right quantity of small-size barges, bulk carriers, and loading/unloading equipment, which could help project managers yield the most production for sand transportation. This paper presents how we developed the simulation model, how it was applied to figure out the optimum combination among various size barges, different bulk carriers, and various types of loading/unloading equipment, for the sand transportation project in Singapore.

Aug 1, 2013

By Saba Gharedash

In this study the results of a series of numerical simulations which are conducted for one of the tunnels of the Mashhad metro line 2 project are presented to evaluate the role of tunnel face support pressure and soil strength parameters on deformation of tunnel lining and face deformation. To achieve this goal, comparative numerical simulations of a mechanized tunnel advance in soft non- homogeneous soil on top of the ground water table and beneath the building are conducted and sensitivity analysis is performed. Development of a step by step tunnel construction process is modeled using a three dimensional finite difference model (FLAC3D) taking into account all the relevant components of shield tunneling. In order to understand the mechanism of the effects of a variety of support pressures on face deformation and lining stresses, numerical simulations are conducted. It is found that the use of different face supports causes a considerable influence on the forces of tunnel lining. In addition, it is revealed that building weight help to change the stress paths and the stress distributions in the tunnel lining.

Aug 1, 2013

By Muhammad Zaka Emad

Cemented rockfill (CRF) plays a vital role in pillar-less mining. Many factors are associated with optimum design of a CRF material. Factors like strength, placement method, mixing, curing time, water content, binder contents, binder composition and additives require to be studied for appropriate rockfill design. The most important factor is strength of a CRF. The design engineer considers fill strength requirements (FSR) for the estimation of CRF strength requirements. Inappropriate CRF strength can cause excessive ore dilution. The recent studies on CRF practices at some of the Canadian mines revealed the most common flaws. Comparison of different types of fill determined that most of the failures occur in cemented rockfill, and the compressive strength can be improved by small addition of sand and mine tailings. This work discusses the studies on determination of unconfined compressive strength, Young?s modulus, density and water contents of CRF being placed in the excavated stopes. It was found that the CRF properties were largely influenced by the variation in gradation and curing time. The 7% binder content improved compressive strength of rockfill significantly but it has an influence on the economics, whereas 4% and 5% binder contents are better choices. The maximum Young?s modulus values were obtained at 28 days curing time for most of the samples.

May 1, 2011

By Anna Maria Venezia

Bimetallic Au-Pd catalysts supported on amorphous silica-alumina (ASA) with vary amount of alumina (0, 8, 14, 28 and 100%) were prepared by the simultaneous reduction of palladium and gold precursors by ethanol in the presence of the polyvinylpyrrolidone (PVP). X-ray diffraction and X-ray photoelectron spectroscopy analyses indicated formation of alloyed Au-Pd particles. Ammonia temperature programmed desorption measurements were performed to monitor the acid strength and the amount of acid sites on the catalysts after their reduction with 10%H2/Ar at 573 K for 1h. The effect of the support acidity on the catalytic activity was investigated in the simultaneous hydrogenation (HYD) of toluene (T) and naphthalene (NP) in the presence of dibenzothiophene (DBT). Coke formation was also determined. Under the selected conditions (P = 5.0 MPa, T = 523 K, WHSV = 41.2 h-1), all the catalysts were resistant to poisoning with 113 ppm of S (as DBT). The hydrogenation activity of toluene and the HDS activity of DBT were found to correlate with the concentration of the medium strength acid sites. The enhancement of the HYD activity and the S- tolerance was related to modifications of the electronic properties of the metal atom upon interaction with the Brönsted acid sites and upon intermetallic interaction.

Oct 1, 2003

By Ray Collier

MINING TODAY l EXTENSIVE AND EXPENSIVE PERMITTING PROCESSES WITH UNKNOWN RESULTS l GENERAL AND IMPASSIONED RESISTANCE TO RESOURCE BASED INDUSTRY l SOPHISTICATED, ORGANISED, AND WELL FUNDED OPPOSITION l MOST LOCAL GOVERNMENT DOESN?T WANT MINING TODAY?S TALK l FOUR SPECIFIC OPERATIONS ON WHICH OUR EXPERIENCE IS BASED ? SECHELT ? CADMAN ? GRANVILLE ISLAND ? LEHIGH CEMENT DELTA PLANT l OUR APPROACH TO COMMUNITY RELATIONS

May 1, 2002

By Barbara A. Filas

The IFC goal is to promote private sector investment in developing countries which will reduce poverty and improve people?s lives. The developing country goal is to promote health, education and employment opportunities that improve their economies and their standard of living. The mining company goal is to Promote successful ?triple bottom line? mining projects that will grow shareholder equity

May 1, 2002

By M. Uszko

The paper presents the conditions for determining the selection of methods for methane drainage in Polish hard coal mines. Various factors for the evaluation of methane drainage performance are used, including the methane drainage effectiveness ratio. However, as will be discussed there are limitations to the methane drainage ratio approach resulting from the characteristics of the deposits extracted in Kompania Weglowa S.A. coal mines.

Aug 1, 2013

By Enrique I. Acuña

Creighton Mine is part of the mining history of Sudbury with more than 100 years of operation. Currently the deeper levels of the mine are reaching the 8000 ft level without implementation of mechanical refrigeration system as a result of the use of the Natural Heat Exchange Area (NHEA) over the past decades. The NHEA of Creighton Mine is part of an old block caving area divided into 4 blocks of trenches that were used to extract the ore. Currently, it is used year round to condition the outside temperature before the airflow enters the fresh air system of the mine. As the mine is progressing deeper, underground temperatures in the lower levels are starting to approach the limit of Vale?s guidelines for working in heat. This paper presents the study developed to improve the management of the NHEA to obtain cooler temperatures at the intake of the ventilation system and outlines the impact to the mine in terms of the additional level(s) that could be operated underground without the use of mechanical refrigeration. This is another of the efforts currently under development for energy conservation and to reduce the capital and operational costs of Creighton Mine while extending the expected life of the mine.

Oct 1, 2010

By Xuehui Xia

Abstract -There are a number of sedimentary exhalative massive sulfide (SEDEX) deposits in the Proterozoic Langshan-Zhaertai rift at the western segment of the northern margin of the North China platform in China, including more than ten large, medium and small deposits located in a belt of 300 km EW by 50 km to 100 km NS, with large Cu, Pb, Zn, Ag, and S reserves. In several representative SEDEX deposits in the rift, the mineralizing elements are prominently zoned, horizontally or vertically, with Cu decreasing but Pb increasing from west to east, Cu decreasing but Zn increasing from bottom to top, and Zn restricted to the bottom half. The ore-hosting rocks, characterized by a clear manganese halo, have developed a polymetallic mineralization in positive relation with their carbon contents. Their isotopic aspects are: ?34S has relatively large positive values, fluctuating between +5‰ and +35‰, compared with Pb isotopic compositions which are less variable, with a model age of 1600 Ma to 1800 Ma, showing that they are mantle-derived. The mineralizing materials were associated undoubtedly with the contemporaneously faulting events in the rift. The deposits owe their origin to seafloor exhalation, with sedimentary rocks as their hosts.

Jan 1, 1999

By M. Abdollahi, M. R. Khalesi, Y. Kianinia, A. Khodadadi Darban

High cyanide consumption during the processing of gold ores with high sulphide minerals can make the typical cyanidation uneconomic. Also cyanide is a toxic material and environmental concerns of cyanide compounds are serious. Optimization of cyanide consumption requires a methodology to estimate the amount of exposed cyanicides, the kinetic of their dissolution and estimation of formation of cyanide complexes which consume the free cyanide. In this paper, a methodology to estimate cyanide consumption by modeling the minerals and gold leaching kinetic based on a liberation model and speciation of all possible cyanide related species in the solution is presented. The results showed that this methodology could successfully estimate the cyanide consumption based on mineralogical data with very lower number of parameters compared to empirical models present in the literature, while it offers the prediction of formation of all cyanide complexes which could be used for optimization purposes.

Jan 1, 2017

By N. Schreithofer, M. Aspiala, R. Serna

The novel attachment timer apparatus presented in this paper serves as a diagnostic tool that allows the detection of changes in bubble-particle attachment probability and therefore floatability caused by alterations in the chemical environment and particle properties. The apparatus consists of six identical capillaries where bubbles with defined size are produced simultaneously in a measurement chamber. The bubbles at the capillary tips are placed in contact with the submerged particle bed for specific time periods, controlled with the help of automatic actuators. The advantage of the instrument is that hundreds of bubble-particle contacts can be measured automatically within a short time period. Microscopic pictures of each measured bubble are taken while recording the movement of the bubble before, during and after contact with the solid particles. The recorded pictures can be used to determine the actual bubble size and its corresponding deviation, and to detect the attachment of particles. The attached particles are collected in a detachable chamber for subsequent characterization. Furthermore, the device is portable and can be taken to the mineral processing plants for quick evaluation of particle-bubble attachment efficiency with particles and process water sampled directly from real processes.

Jan 1, 2017

"THE OTTAWA BRANCH, CIM, each year holds a symposium on a subject of topical interest. The symposium this year was on Canada's Offshore Mineral Resources, at which papers were presented by: Dr. Donald G. Crosby, chief, Resource Administration Di-vision, Department of Energy, Mines and Resources, Ottawa; John A. Beesley, head, Legal Division, Department of External Affairs, Ottawa; and David W. Smith, man-ager, offshore exploration and production, Shell Canada Limited, Calgary. Because of the interest which this topic holds for our members, and because of the wealth and significance of information presented, the three papers -representing the first comprehensive review of our offshore resources -are reproduced herewith. The opening remarks of the Chairman, Dr. F. K. North, Professor of Geology, Carleton University, are also recorded, together with a few of the questions asked by the large attending audience. The symposium was held February 13th, and was organized by Dr. W. M. Tupper, chairman of the Branch Program Commit-tee. Differences in the extent of the continental shelf will be noted in the papers. These differences are related to slightly different definitions of the continental shelf by the authors."

Jan 1, 1969