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By K. Madi, E. Yeugo Fogaing, S. Forest, M. Boussuge, L. Massard, M. Huger, Gaultm C.

This study has been carried out owing to the French research program PROMETHEREF, which aims to improve the knowledge of thermal and mechanical properties of industrial refractories at high temperature. In this frame, this paper relates a collaborative study between Saint-Gobain CREE, R&D Centre for Saint-Gobain Ceramics & Plastics in Europe (Cavaillon), the Materials Center P.M. Fourt of Ecole des Mines de Paris (Evry) and the Research Group on Heterogeneous Materials (GEMH) of ENSCI (Limoges). Data collected at high temperatures by using different means (bending tests, ultrasonic measurements,...) allows the identification of the high temperature behavior of two fused cast materials, produced by Saint-Gobain group for the glass manufacturing industry. The results emphasize the importance of the transformation of zirconia and of the viscosity of the glassy intergranular phase on the mechanical behavior. Damage under the form of microcracking caused by thermal expansion mismatch between the phases is also observed during cooling down at low temperature, when the material is elastic.

Jan 1, 2004

By J. M. Belland

This paper deals with the geology of the Smallwood mine in relation to its influence on mining and milling operations. Structure within the orebody, and variations in ore grade and material types, will be described and associated with the various drilling, blasting and milling operations. The orientation of planes of weakness, either bedding or jointing planes, and contacts between extremes in material types influence the size of the broken material. Generally speaking, variations in grinding rates and recovery can be associated with stratigraphic sequence and metamorphism.

Jan 1, 1966

By H. L. Cameron

Introduction Since the beginning of gold mining in Nova Scotia in the year 1860, the biggest problem o the mine operators has been to find and follow the ore zones in the narrow quartz veins. It was early recognized that all veins were not gold bearing and that, in those that were, the commercial ore was confined to limited zones. A large number of geologists and mining engineers have been interested enough to give time and thought to the problem, but, until the last four or five years preceding World War II, they were handicapped by lack of exact data from mining operations. The necessary data could only be obtained by daily checking of underground operations. Such daily checks were instituted at a number of mines during the period 1935-40 and, in every case, were successful in delimiting the ore zone or zones for the particular mine. The present paper deals with the results of this work as applied to practical ore finding. It is an attempt at extrapolation, from observations in the four districts with which the writer is personally familiar, co other districts in which similar conditions or structures are reported.

Jan 1, 1947

By A. -I. Abenhaim, I. Sasu, C. Perron, I. Mantegh, S. Larose

Manufacturing long shafts, such as those used in turbine engines, normally involves with drilling inside them in order to take the excessive mass out. Concentricity between the shaft axis and that of the drilled hole is very crucial as it impacts the mass distribution around the axis of rotation. It is important that the shaft mass be well balanced around the central axis in order to minimise the centrifugal forces on the bearings and supporting structure as well as any unwanted vibrations. The eccentricity problem, mostly in long shafts, comes due to machining limitations. It is difficult in long shafts to maintain the concentricity tolerances while drilling inside the shaft. In this work, we address the problem of correcting this eccentricity problem, i.e., when the axis of the inside hole deviates from the central axis. The presented work is based on a threepoint bending method and investigates its effect on the residual stresses and plasticity regions induced on the shaft. A full finite element model is presented that can used to design the solution parameters (bending load, location, etc.) and predict the effect. Limited experimental results are also presented to validate the finite element modelling.

Jan 1, 2006

By A. Roca, V. A. Quezada, O. A. Benavente, M. Cruells

The leaching pretreatment of copper ores is widely used in the Chilean mining industry. Agglomeration and acid curing have been identified as the most useful pretreatments. Of these, acid curing was recognized as beneficial in the dissolution of copper minerals, even in sulphides such as chalcopyrite. Extensive acid curing times have an impact on copper extraction, generate a homogeneous acid distribution in the mineral bed and benefit the inhibition of aluminum-silicate minerals (acid consumers). This document describes some of the theoretical background and results regarding the effect of acid curing in a chalcopyrite sample with 74% purity according to Qemscan analysis and a 28.5% of total copper. Leaching tests are carried out at 25, 50 and 70°C, evaluating the effect of a pretreatment on the chalcopyrite dissolution. The original sample and products generated were characterized by X-ray diffraction analysis and Scanning Electron Microscopy (SEM). The performed experiments indicate a direct relation between the effect of curing time and temperature in copper extraction. 92% of copper can be extracted in a leaching at 70°C and with 15 days of curing. Elemental sulfur, jarosite and copper polysulfide (CuS2) have been detected in leaching products. INTRODUCTION The copper extraction from minerals is a technique that has been developed for hundreds of years in the world. In 2017, the largest copper producer was Chile, exported 5.5 million tons (COCHILCO, 2018). However, in order to preserve this production level means overcoming multiple challenges. In the case of the Chilean copper deposits, the average copper grade in 2016 was 0.65%, lower than the 1% declared in 2004 (Consejo Minero, 2018). This is mainly due to the deeper of the deposits reaching sulfide mineral zones, mainly chalcopyrite. Traditionally, these sulfurized zones ore are treated through concentration by flotation and subsequent pyrometallurgical treatments. However, for some copper companies it is complex to process by this alternative, due to the high costs and high rates of water consumption. The mineral resources of these companies are known as "low-grade sulfides" and do not allow, economically, the treatment of these minerals through concentration by flotation. This is how hydrometallurgy becomes an alternative for the treatment of this type of deposits. In addition, several companies have hydrometallurgical plants, which would allow the operational continuity of these plants.

Jan 1, 2019

By K. Nagai

The Asian projects are now in their second terms after the five-year first terms. Ultrafined-grained steels were developed in lab-scale and/or in practical process. Basic approach has been performed to explore the evolution mechanisms of ultrafine-grained microstructures. There have been investigated two approaches to make the ultrafine grains: the "recrystallization route" and the transformation route. In the "recrystallization" route, heavy deformation at low temperature is necessary for the ultra-refinement. In the transformation route, making the high density of ferrite initiation sites in the deformed austenite, especially of the heavily compressed austenite structures, is essential for the ultra-refinement, and further hindering the ferrite growth is also inevitable to utilize the high initiation rate. Strength and toughness are dramatically improved by the ultra-refinement. Fatigue property is also excellent. The poor uniform elongation can be enhanced by the design of the second phase dispersion. At the same time the application has been also pursued from various viewpoints of engineering to take advantages of the ultrafine-grained steels. Bridge, ship, construction, automobile and other high strength parts are being attempted for the application.

Jan 1, 2004

By R. Loj

Katowice Coal Holding (KHW) is one of the largest coal companies in Europe. The company owns five coal mines with a daily output of around 60 000 tons of coal. In the Katowice city area, very good quality steam coal is extracted. The depth of mining varies between 400 and 1100 m and some of the mines rank amongst those most afflicted by methane in the Upper Silesian Coal Basin, with the methane hazard having a significant impact on production and safety. ?Myslowice-Wesola? mine, being a part of the Katowice Coal Holding is characterized by high methane and rockburst hazards. The mine is equipped with a modern surface drainage pumping station. At the mentioned mine, longwall 514 was selected for analysis of its methane emission. The longwall was extracting the thick seam 501 (over 4 m), at a depth of over 900 m, which was subject to high stress and high gas concentration conditions. At a distance of about 50 m above, seam 501 is covered by thin seam 416. The strata between these two seams are sandstone and mudstone layers. In the floor of seam 501, with a thin shale interlayer, is located seam 510, which is the thickest (over 10m) and richest coal seam in the Upper Silesian Coal Basin. In longwall 514 and it?s vicinity, methane was the dominant risk. For this longwall three methods of classical gas drainage were carried out. At first, drainage was undertaken using long boreholes from a cross-cut at level 665 m, located far from the production panel. Later, it was performed using typical boreholes drilled from the ventilation gallery (tail gate road). Finally, it was undertaken using a degassing drift executed in the upper coal seam 416. All of these headings, ie. cross-cut level 665 m, the ventilation road and conveyor road in seam 501 and the degassing drift in seam 416, were equipped with media for drilling and proper drainage pipelines. Due to the high rockburst hazard and some problems with caving, several kinds of de-stressing and torpedo blasts were carried out in both coal seams and roof rocks. The subsequent analysis and experiments allowed the establishment of some general rules for carrying out degassing operations effectively. The effectiveness of a degassing drift was demonstrated. In some instances, the system allowed more than 70% of the total methane released to be captured and fed into pipelines. The aforementioned blasts had a marginal impact on methane emissions and the efficiency of degassing methods. Cyclic drilling and regular switching of boreholes in phase with the mining progress and working face advance were shown to be essential.

Aug 1, 2013

By Z. Q. Liu, J. M. Du

"On the basis of analyzing current design and applications, the structure form, working loads and design principles of shaft sinking headframe are summarized in this paper. To overcome the insufficient bearing capacity and geometry size of the finalized shaft sinking headframe in China, a series of new large shaft sinking headframe were developed under vertical shaft construction conditions of maximum net diameter of 12.0 m and maximum depth of 1200 m. The new series shaft sinking headframe include two sets (with single sheave platform and double sheave platform), three dimensions (optimum shaft diameter <8.0 m, 8.0-10.0 m, and 10.0-12.0 m, respectively) for each set, and has innovation and optimization on structure of the sheave wheel platform (MU type) and bracing frame (REN and ZHONG type). The largest new shaft sinking headframe can arrange up to 4 hoisting equipment simultaneously and has bearing capacity more than 10000 kN. Two of the new shaft sinking headframe were successfully applied in practical engineering, such as the Hulusu auxiliary shaft, the Dahaize 1# auxiliary shaftand Sishanling auxiliary shaft. These applications showed that the new shaft sinking headframe has sufficient bearing capacity and reliable applicability. The new shaft sinking headframe could provide an effective guarantee for safety and efficiency sinking of deep-large shaft in the future.INTRODUCTIONShaft sinking headframe is one of the basic shaft sinking structures and it is mainly for hanging hoisting containers and sinking facilities in sinking a vertical shaft (Yu & Shi, 1991; Wang, Jing, & Liu, 2007). Currently, 7 types of steel pipe sinking headframe are used in China, which are mainly finalized by the Ministry of Coal Industry of China (Wang, 1988). As shown in Table 1, V-type is the largest of them and it is only suitable for sinking shaft of diameter less than 8 m and depth less than 1 000 m(Yang, 1982). However, with the increase of mining depth and scale of mineral resources in China, the diameter and depth of newly built vertical shaft are increasing continuously (Xie, Zhou, Xue, Wang, Zhang, & Gao, 2012; Qi & Pu, 2013). At present, the maximum net diameter of vertical shaft is close to 12 m, and the maximum depth is more than 1600 m (Yang & Chen, 2015; Xu, Yang, Liu, & Qin, 2015). The shaft sinking headframe has become the main restrictive factor for the development of sinking equipment, such as the height of muck discharging platform cannot meet the usage requirement of hydraulic umbrella driller, the size of sheave wheel platform is difficult to arrange the increasing hoisting and suspension equipment, the bearing capacity is insufficient to meet the needs of multiple hoisting loads in sinking a deep-large shaft, etc. Therefore, development of new shaft sinking headframe for deep-large shaft (>1000 m in depth and 8~12 m in diameter) is urgently required for China and also the whole world."

Jan 1, 2019

By C. Guo, R. J. Chalaturnyk, M. MacKinnon, J. D. Scott

The Mildred Lake Settling Basin (MLSB) is the largest disposal site for mature fine tailings (MFT) at the Syncrude Canada Ltd. oil sands plant. Over the past years (since 1996), there has been a marked change in the densification behaviour of MFT in the MLSB. Methane-producing microorganisms, known as methanogens, have become very active, and large amounts of biogas (mainly methane) have been produced. Continued field monitoring of the MLSB has provided convincing evidence of the rapid densification process (rapid water drainage from the tailings) at the area with intense microbial activity. This rapid densification has caused pumping challenges in the transfer of fine tailings from the Mildred Lake Settling Basin for the creation of composite tailings. It may also have potential positive effects in accelerating the reclamation of the oil sands fine tailings. A field and laboratory research program was carried out to study the mechanism leading to the rapid densification phenomenon. A review and discussion of the research program is given and some results from the field investigations and small-scale column tests are presented in this paper.

Jan 1, 2007

By Z. Y. Ma, H. Y. Yang

The process of microwave-ultrasound assisted leaching of valuable metals from copper anode slime was proposed in this paper. Design of experiments has been used to study the effect of the main leaching parameters, such as microwave power, ultrasound power and reaction time. The central composite design (CCD) was used to predict the maximum leaching efficiency of copper, tellurium and selenium. The experimental data obtained were fitted to a second-order polynomial equation, and they also were analyzed by analysis of variance (ANOVA). The 3-D response surface plots and the contour plots were applied to determine the optimal conditions. The optimum conditions of microwave-ultrasound assisted leaching process were: microwave power 834W, ultrasonic power 638W and reaction time 403s. Under these conditions, the experimental leaching efficiency of copper, tellurium and selenium were 98.88±0.56% 98.96±0.78% and 98.57±0.67%, respectively, which agreed well with the predicted values.

Jan 1, 2014

By G. Marchand, R. H. Hay, E. C. Pearson

"AbstractA polishing .technique is described together with two anodic etching methods for aluminum and its alloys. Some of the optical and structural characteristics of the film formed by •these etching methods are discussed and it is shown to what degree these properties of the film are related to the crystallographic orientation of the metallic substrate. Applications to the study of recrystallization and twinning phenomena and to the study of plastic deformation, banding, and texture estimation are discussed. Micrographs are shown .to illustrate the manner in which the technique is particularly well suited to the study of such phenomena.IntroductionThe physical metallurgist is constantly faced with the problem of polishing and etching of metallic sections. Mechanical polishing is tedious, time consuming, and not applicable whenever a surface entirely free from plastic deformation is required. Etchants are generally required to reveal the grain structure in order to determine its size, shape, and regularity, or to bring up constituents. In the case of aluminum, the .most common etchant to reveal grains is a mixture of three acids: HC1, HN03, and HF. This etchant is fairly satisfactory on certain alloys and for certain metallurgical conditions but in general fails to give a good definition of the grain on castings, on highly alloyed products, and whenever the grain is smaller than 100 microns in diameter. Besides size and shape, a grain, or crystal, has an orientation and may be endowed with several types of imperfections."

Jan 1, 1952

By P. C. Sui

Numerical investigation and parametric simulations of the coupled electrical conduction and mass diffusion in the GDL of a PEMFC are reported. The coupled transport is solved using a 2D, "under-the-rib" computational domain for the cathode GDL. The current density on the GDL/catalyst layer interface, which constitutes one of the boundary conditions for the GDL domain and reflects the activation overpotential in the catalyst layer and the ohmic loss in the membrane, is solved iteratively using a novel numerical algorithm. A parametric study is performed to investigate the effects on current density distribution of various operating conditions such as oxygen concentration and membrane resistance, and of design factors such as GDL geometry, anisotropic transport properties, and deformation under the land area. The results show that the current density distribution under the land area can be dominated by either electron transport or mass transport, depending on the operating regime.

Jan 1, 2005

By O. Espinoza Ortega, S. Song

A process scheme has been devised to improve the silver recovery and the grade of concentrates from the scavenger concentrate of a silver ore flotation circuit. Based on modal analysis studies it was found that silver sulfide minerals in the scavenger concentrate were associated as simple binary particles and finely disseminated in sulfide and non-sulfide gangues. Fine grinding of the concentrate improved the grade-recovery curve of silver to a very limited extent owing to heterocoagulation between liberated fine silver sulfides and coarse particles of gangue. This heterocoagulation phenomenon was prevented by grinding the concentrate in the presence of the dispersing reagent sodium hexametaphosphate. The silver grade-recovery curve was improved by practicing. before the conventional flotation step, a selective aggregation step for the fine silver sulfide particles using the non-polar oil kerosene, the sulthydryl collector Aerophine 3418 and conditioning the pulp under strong agitation conditions.

Jan 1, 2004

By S. N. Aliferova, E. I. Afonina, S. N. Titkov, A. Ju. Bondareva, N. N. Panteleeva

"Potash ore is mainly processed using the method of cationic flotation. Potash ore deposits of the CIS, namely: at Upper Kama river, Gremyachinsk (Russia), Starobin (Belarus), Tubegatan (Uzbekistan) are characterized by relatively low KCl impregnation (1.0 – 1.5 mm) and contain up to 10% of waterinsoluble impurities (WII). Water-insoluble impurities are presented by aluminosilicate, silicate, carbonate (calcite, dolomite) minerals and anhydrite. In the process of milling the ore to a flotation size there are released and dispersed the insolubles impurities actively sorbing the cationic collector, i.e. aliphatic amines C16 – C22. In this regard there is carried out a preliminary desliming of the ore.Currently grinding the ore to a flotation size (1.5 mm or less) is carried out in rod mills along with forming of a large number of fine-grained ore fractions having the size under 0.25 mm, which results in the increased KCl losses with halite slime waste and reduction in the quality of finished product. There has been developed the technique for processing of potash ores with a high content of water-insoluble impurities (10 – 12%) containing, in different ratios, silicates, carbonates and anhydrite. The technology involves the use of the ore dry grinding to the flotation size and subsequent reagent activation of the processes for sludge removal and sylvite flotation.INTRODUCTIONCurrently there are being developed the potash ore deposits in the CIS countries, namely: at Upper Kama river and Gremyachinsk deposits (Russian Federation), Starobin deposit (Republic of Belarus) and Tubegatan deposit (Uzbekistan). Potash ores are a mixture of sylvite and halite and contain water-insoluble impurities of silicates, carbonates and anhydrite. The content of water-insoluble impurities (WII) reaches up to 10%, disseminated (impregnated) sylvite does not exceed 1.5 mm and in connection with that the ore is crushed to a particle size under 1.5 mm. Ore grinding is performed by wet process in rod mills with producing a significant amount of fine-grained mineral fractions and sludge, which are actively sorbing a cationic collector, i. e. primary aliphatic amines C16 - C22. The ground ore is deslimed and the slime product is directed to a sludge depot (pits)."

Jan 1, 2016

By S. Feinstein, I. Reznik, Y. H. Hatzor, O. Shitrit, Y. O. Rosenberg, H. J. Vinegar, S. Nguyen

"We report the effects of porosity and total organic carbon (TOC) content on the mechanical behavior of organic-rich chalks, based on laboratory measurements. The organic-rich chalks are from the Senonian Ghareb and Mishash formations. This deposit is an immature oil-prone source rock, about 300 meters thick, situated at shallow depths (several hundreds of meters) in the Shefela basin in central Israel. The study is based on core data collected from the Zoharim borehole.Three main phases comprise the bulk volume of this rock: 1) carbonate mineralogical phase (predominantly calcite); 2) pores (mostly saturated with brine); and 3) solid organic phase (type IIS kerogen). The mechanical effects of porosity (23-45%) and TOC (4-19%) are evaluated based on bulk incompressibilities vs. volumetric fractions analysis. Volumetric fractions of mineralogical and organic phases were obtained by porosity, density and TOC measurements. Saturated rock bulk moduli were measured through ultrasonic velocity measurements. Saturated rock bulk moduli correlate best with the sum of kerogen and pore volume fractions, rather than each of them separately. The volumetric fractions were also used to define the range of bulk modulus of the organic-rich chalk, using the Hashin-Shtrikman upper and lower bounds. Based on Marion's Bounding Average Method (BAM), the normalized stiffness factor of the chalk averaged at w=0.197, indicating a soft pore geometry. Using the average normalized stiffness factor, the BAM predictions showed excellent match with the saturated rock bulk modulus and the sum of kerogen and pore volume fractions. Based on our findings, it is inferred that kerogen grains do not support the solid skeleton but are distributed between the minerals grains. We also propose here a straightforward approach for calculating the Hashin-Shtrikman bounds, based on TOC and porosity measurements. The mechanical effects of porosity and TOC indicated here are very important for the understanding of the influence of immature kerogen presence in highly porous chalks, as the Ghareb and Mishash formations."

Jan 1, 2015

The problem of thin and very thin coal seam extraction in a long perspective of Ukraine?s fuel and energy industry development was determined. Technical and economic benefits of coal seams selective mining technique including beneficial environmental impact were substantiated. The scientific and practical aspects of development of borehole underground coal gasification (BUCG) technology are considered. The technological scheme of underground gas generators is offered on the basis of the authors? criteria of fitness and adaptability to the mine and geological conditions. These charts foresee the preparation of gas generators from earth surface and directly from the present mine working by inclined horizontal boreholes. Basic research is directed at abandoned supplies extraction in coal mines. Concepts of technological decisions and technical implementation of the underground part of the gasification system are worked out with analytical models, with subsequent test verification on special options and a mine experimental gas generator. Forming the technological scheme of gasification is founded on the basis of tying up spatial and sentinel factosr of coal seam gasification taking into account sufficient impermeability of the system a «gas generator ? rock massif» and to dirigibility by thermochemical processes that flow in a rock massif. The offered solutions contain the possibility of creation of the power and chemical enterprises of gasification, taking into account the complex use of BUCG products in the ecologically reserved technological cycle. Gas generator efficiency is evaluated from an economic standpoint.

Aug 1, 2013

By A. K. Alzo?ubi

Block toppling in natural rock slopes has been under investigation since the 1970?s. De Freitas and Watters (1973) introduced the term ?toppling? to describe the movements of rock slopes by rotation in steeply dipping beds. The Lornex pit case history from British Columbia (Canada) was chosen to study the effect of mining on the stability of toppling rock slopes. A discrete element approach that allows fracturing of intact material was applied successfully to model the composite rock slide-rock topple movement. Three main movement modes were observed in the field and the numerical model; the sliding of the top of the slope exposed normal scarps, the toppling at the middle part of the slope exposed obsequent scarps facing opposite to the slope face, and dilation of the rock caused by fracturing at the toe formed loose material. The development of the rupture surface at the toe of the slope was traced and did not evolve into a continuous rupture surface throughout the slope both in the field and the numerical simulation. Good agreement was achieved between the deformations recorded in the field and the numerical simulation.

Jun 1, 2012

By T. Wajima

"A novel carbonaceous adsorbent for recovery of nickel from nickel plating waste solution was prepared from rice straw using sulfur impregnation. The rice straws were cut to 1 cm pieces, and then immersed in 0.01 - 3 M K2S solution to prepare sulfur-immersed materials. The immersed-materials were heated at 100-700 ºC in nitrogen gas to produce the sulfur-impregnated carbonaceous adsorbent by pyrolysis. The contents of carbon and sulfur in the adsorbent and abilities of adsorbent to recovery nickel from aqueous solution were examined. The contents of carbon and sulfur in sulfur-immersed materials are almost same as those in raw material. In pyrolysis, with increasing the heating temperature to 200 ºC, the contents of carbon and sulfur are almost constant, and then above 300 ºC those increase. The recovery for nickel using raw material, sulfur-immersed material and the product pyrolyzed at 100 - 200 ºC are almost same, and with increasing the heating temperature to 400 ºC, that of the product increases, and above 500 ºC that of the product decreases. In immerse step, with increasing K2S concentration, the carbon content of the product at 400 ºC gradually decreases, the sulfur content of the product increases, and the recovery for nickel using the product gradually increases and then above 1 M K2S decrease. The product prepared from material immersed in 1 M K2S solution at 400 ºC indicates a maximum recovery for nickel ion. The product can adsorb nickel ion in nickel plating waste solution coexisting with phosphate ion, and adsorbed nickel ion in the product was deposited as nickel metal after heating at 1000 ºC under N2 atmosphere.INTRODUCTIONRice is the second world’s largest cereal crop after wheat, but produces large amount of straw residues, of about 330 million metric tonnes. Rice is a widely grown crop in Asia, and rice straw is produced as a by-product of rice production. In most parts of rice fields, open-field burning of rice straw is commonly practiced in the region when there is limited time to prepare a field for the next crop. However, open-field burning of crop residues is an uncontrolled combustion process during which air pollutants are emitted into atmosphere. These air pollutants have significant toxicological properties and are potential carcinogens (Gadede et al., 2009). Although wildfires are prohibited in cultivation fields of most countries, farmers usually keep on burning their crop by-products. Biomass burning is an important source of aerosol particles which may affect local and regional air quality (Gao et al., 2011), and also contribute to global climate changes."

Jan 1, 2016

By M. J. Sapko, R. W. Watson, E. S. Weiss

The relative incerdivity of several blasting agents was evaluated in the Bureau's Bruceton Experimental Mine (BEM) . The minimum charge weights resulting in the ignition of predispersed oil shale dust clouds were measured for each of the explosives. A 400 g unstennned charge of ANFO (ammonium nitrate-fuel oil) was sufficient to initiate an oil shale dust explosion, whereas a 1000 g unstenuned charge of an emulsion blend did not ignite the dust even with the addition of 4% methane gas. Several stenuning materials were evaluated in the BEM for their effectiveness in preventing the ignition of near stoichiometric methane-air mixtures. Water stenuning was superior to all other inhibitors tested against methane. Explosibility testing of fine sulfide ore dust in a 20 L chamber and in the BEM show that the dust is capable of propagating an explosion given nominal concentrations of 700 to 800 g/m3. Results are encouraging and irrlicate that there is merit in pursuing explosive composition as a means of reducing ignition probability of oil shale and sulfide dust clouds generated during nonnal blasting operations. The proper selection of explosives and stenuning materials should significantly reduce the probability of secondacy dust explosions in oil shale and sulfide ore mining.

May 11, 1988

The system of keeping geological plans and sections for the Geco Mine at Manitouwadge, Ontario, is described. Special methods employed to save draughting time with-out sacrificing accuracy, such as the extensive use of black line prints, are discussed. The uses made of the plans and sections by the mine planning engineers in their designs of stopes, and by the blast-hole engineer in ~is preparation of blast-hole layouts, are noted. An unusual scheme for portraying the distribution of .copper, zinc and silver values within the ore zone is de-scribed. The method of estimating the grade of ore to be "blasted in each ring of blast holes is outlined, as is the method of estimating the annual ore reserves. The design of an effective but simple transparent geo-logical and mine development model, used as a display for -visitors, is discussed. A large-scale model used for the study of problems in geological structure is also de-scribed.

Jan 1, 1964