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By Yvon T. Maurice

Under the auspices of the Federal-Provincial Uranium Reconnaissance Program, a geochemical orientation survey was undertaken in an area of uraniferous Lower Proterozoic (Aphebian) rocks near Cape Dorset in southwest Baffin Island. The main objective of this study was to establish a methodology for a future reconnaissance geochemical program using lake samples over a 300-mile Lower Proterozoic rock belt that occurs along the southern coast of Baffin Island. Mineralogical and chemical studies of known radioactive occurrences, combined with detailed sampling of secondary environment media in the vicinity of the showings. indicate that uranium is the most significant pathfinder, despite considerable enrichment of other metals in the uraniferous rocks, Significant geochemical patterns produced by uranium in lake waters and uranium in lake sediments have been obtained, but their relative usefulness depends on the distribution of carbonate bedrock, which in turn affect the bicarbonate content of lake waters. In southern Baffin Island, because of erratic variation in lake-water alkalinity, it is recommended that both water s and sediments be sampled on a routine basis. The need for lake-water acidification to prevent depletion of soluble metal ions in samples resulting from adsorption on the walls of the containers and/or suspended solid matter is discussed briefly. The base metal potential of the area was examined in some detail and found to be significant, particularly for a Lower Proterozoic gossanous formation that occurs throughout southern Baffin Island.

Jan 1, 1977

By D. H. d Hamly

THE work of Brown and others at Pittsburgh (Brown, Baum, Yant, and Schrenk, 1938)(1) and the success of their light field microprojector (Figure 1), have shown that the microscopy of dust quantitation can be greatly improved. It has been shown that dark-field microprojection of dust spots on konimeter slides is possible (Pullen, 1940), and this paper is a discussion of the new microprojector and a new counting method which is made practical by this instrument. The microscope makes possible the ready determination of the dustiness of mine ventilation air. Reduction of the dust concentration from a dangerous to a safe level involves one or more of the following: reduction of dust production, filtration of the air stream, or dilution with non-dusty air. Each of these raises important engineering problems of time and costs, and trustworthy information on the state of dustiness of the air is required ?both before and after the employment of any method of reduction. Records of this information may be divided into two broad classes concerned with safety: (1) the level of dustiness, and (2) the quantity and kind of dust produced by a machine under a given set of conditions. Though the first requires only one determination for a given time and place, numerous routine records are required to show the continuous safety of the air in an actively producing mine. Though repeated samples are required, highly accurate counts are not needed to show safety or to indicate whether a substantial increase in the non-dusty ventilation air has produced a proportionate decrease in the dustiness of the mixed air. The Devers and Gathercole konimeters have proved satisfactory instruments for this purpose in Ontario.

Jan 1, 1942

"Mining with blast holes drilled upwards may be done to recover sill pillars, or for economic reasons when the distance between the levels is relatively large. If the rock is sufficiently competent to accommodate large stope size, the distance between sublevels could be increased to as much as drilling accuracy allows. The same drill drift can be used for the drilling of both down holes and up holes. In the case of down holes, the initial opening of the stope (drop raise) is not as much a problem as for the inverse drop raise for mining with up holes. This is because, with a drop raise, a lot of space is available at the toe for the blasted rock to expand. In addition, the raise can be blasted in many shots, thus allowing smaller blasts each time. Inverse drop raises are generally much more difficult to blast because of the limited space for muck flow, and must, therefore, be taken down in a single blast, requiring special considerations in order to ensure a success. A case study of a 29 m (95 ft) inverse drop raise successfully blasted in a single shot at Heath Steele Mines is described. The paper covers technical considerations such as drilling accuracy, hole deviation survey, delay extension and protection, initiation methods and initiation sequence. Finally, a novel method for creating the initial opening called ’slot drilling’ is presented. This method, inspired from LKAB in Sweden, consists of drilling a row of interconnected holes using a special guide mounted on a regular production drill hammer.With a case study of blasting an inverse drop raise of 29 m (95 ft) in one blast, this paper further discusses some technical issues that are critical for the development of inverse drop raises. A novel method for creating the initial opening with a slot of interconnected holes is also presented with the experience acquired at different mine sites across the Noranda group."

Jan 1, 2000

By J. C. Motz

With ore grades continually decreasing and finer mill feed requirements, it becomes increasingly important to have the capability to handle the larger tonnages economically. With the 10 ft. Standard capable of reducing 1,633 metric tons per hour (1,800 short tons per hour) to 80 percent passing 50 MM (2 inches) and the 10 ft. Short Head following to produce a mill feed of all minus 12 MM (1/2 inch) at a rate of 608 metric tons per hour (670 short tons per hour), we feel significant savings will be realized in installation and operating costs. The largest concentration of cost in the secondary and tertiary crushing stations is the building itself that houses the process equipment. An example of the savings to be attained can be seen from an examination of a 40,820 metric ton (45,000 short ton) per day crushing plant. A total of nine 7 ft. Symons Cone crushers is used to generate 12 MM (1/2 inch) ball mill feed. The average center distance between units is 6.1 M (20 feet) and allowing a 6.1 M (20 feet) nominal distance from the centerline to the wails, the building becomes 61 M (200 feet) long. For this production rate, four 10 ft. Symons Cone crushers would be required. With the 10 ft. crushing plant requiring a center distance spacing of 7.6 M (25 feet), the building length totals approximately 38 M (125 feet). Construction costs vary depending on location, but a reduction in building length from 61 M (200 feet) to 38 M (125 feet) will result in estimated savings of between $2,500,000 and S4,000,000. While the 10 ft. Symons Cone has been involved in a number of feasibility studies for some time, the Process Machinery Division of Rexnord commenced detail design work on the 10 ft. Cone crusher in 1972. For comparison purposes, the 10 ft. and 7 ft. capacities are given in Table 1.

Jan 1, 1978

By U. Ulusoy

Surface roughness and acuteness are known as the two of the main properties of the particle morphology affecting the behavior of the powders in the process. Since the techniques used for the morphological characterization of powders by 2-dimensional microscopic measurement from the polished sections that have some disadvantages, the 3-dimensional analysis has often relied on measurements of particle morphology. A review of literature data was presented for high-grade barite and pyrite particles ground by ball and autogenous mills to determine the morphological properties using a new 3-D approach based on BET nitrogen gas adsorption and Permaran methods. Micromeritics Flowsorb II 2300 instrument which employs BET nitrogen adsorption technique was used for the specific surface area measurements and the roughness of the particles. Permaran (manufactured by Outokumpu Oy) was used for the measurements of airflow resistance of powder samples for the acuteness. Spherical glass beads were used as reference sample for the acuteness measurements. The obtained parameters, which are surface roughness and acuteness, were corre-lated with the floatability performance of those mineral particles. The flotation performances of those particles ground in different mills (ball and autogenous) were also evaluated by a Hallimond tube. The results showed that lower roughness and acuteness values caused higher flotation recoveries for both barite and pyrite particles that were tested independently in different type of the mills. In other words; particles with smooth surfaces resulted in better floatability for barite and pyrite minerals studied.

Jan 1, 2014

By J. Y. Hwang

Microwave heating is an attractive alternative to conventional heating methods because heat is generated directly within the microwave absorbing materials. It has potential to be utilized for selective heating and removal of specified components from a materials mixture. This investigation was undertaken to explore the potential of selective heating and burning of binders for foundry sand reclamation. Selected raw materials and binders used in foundry operations were tested to determine their receptivity to microwave heating. Time needed to reach 600°C and/or the maximum temperature achieved for samples irradiated by microwaves for twenty minutes under 800 W microwave power are reported. The microwave heating characteristics of the selected materials are summarized and discussed. The interactions between microwaves and the raw materials used in a foundry. such as silica sand. chromite sand and bentonite (clay) binder were studied. The results showed that chromite sand coupled well with microwave energy at ambient temperature while silica sand did not. This was expected because the major component of chromite sand. iron chromite (FeCr2O4). is a good microwave absorber. while quartz, which is the major component of silica sand, is a microwave transparent material at ambient temperature. Bentonite absorbs microwaves well because it contains a hydroxyl functional group and water molecules in its structure. It was found that the structure of bentonite was changed through microwave irradiation. Microwave heating characteristics of silica sand mixed with different amounts of bentonite binders were investigated. The presence of bentonite in the mixture improved the microwave heating of silica sand significantly. and bentonite was deactivated by the microwave processing.

Jan 1, 1995

By H. Ito, T. Takasu

Effects of a mechnochemical treatment to oxide Ni ores have been investigated to enhance the extractive ratio of Ni from them in acid leaching process. High intensity grinding by a planetary boll mill showed strong effect to enhance the extractive ratio of Ni, for example , 10% of extractive ratio of Ni in sulfuric acid leaching(0.05mo1/1,at room temperature) increased to more than 90% with 60min. of planetary boll milling. Effects of additives(sulfur and some oxidants) on the mechnochemical treatment have also studied. Sulfur showed almost no effect to enhance the total Ni extractive ratio but increases the selectivity of Ni extraction. More than a half of Ni could be extracted by water when Ni ore was grinded at addition of Na2S207 in the milling treatment. Some effects of mechnocemical treatments to Ni ore are summarized in this paper.

Jan 1, 2005

By Larry Hopkins

The molten metal circulation pump has become a staple for melting aluminum in reverberatory furnaces. The forced convection that is created in the melt efficiently provides circulation while dramatically improving melt rates, lowering fuel consumption, extending refractory life, and providing metallurgical homogeneity. Two metallurgical guidelines that are important to many casthouses are molten metal inclusion levels and hydrogen gas content. In order to improve molten metal quality, furnace and casting practices must 'manage these molten metal defects, Today specialized in-line degassing and filtration equipment is used downstream of the furnace to accomplish these tasks. In contrast, the molten metal gas injection pump has metallurgical contact time in the process for hours during the charging/homogenization cycle. The qualitative benefits of employing a gas injection pump to "pre-clean" are outlined and discussed against historical empirical information obtained with alternate methods. Further, a recent study quantifies the merits of this gas injection technique as an effective molten metal quality improvement tool. Specifically, the effects on inclusion level as determined by PoDFA?, gas content as determined by A1SCAN? sampling and alkali metal content as determined by spectrographic analysis are examined in relationship to various gas feed compositions and flow rates.

Jan 1, 1995

By C S. Walker

This paper analyzes the physical, operational and economic site conditions which were conducive to the design of a diesel-electric power plant wherein the over-all use of the thermal energy of the fuel exceeds 80 per cent. The heat energy supplied to the diesel engines is recovered in power generation, vapour phase cooling, waste heat boilers, air to exhaust gas heat exchangers and lubricating oil coolers. Electric boilers are also integrated into the plant design to enable the ratio of electric power output to heat recovery to be varied to suit the seasonal and daily variations. The criteria relative to thermal and electric power design requirements are discussed, and the design details of some parts of the plant which conform to these criteria are illustrated. Some data in regard to the actual operation of the plant over a short period are also included. Introduction THE Cantung mine (Canada Tungsten Mining Corporation) is located some 180 miles north-east of Watson Lake, Yukon Territory. It is situated on the upper reaches of the Flat river at an elevation of about 3,700 feet.

Jan 1, 1965

By F. N. Smith

The carbon steel casings of Heat Recovery Steam Generators (HRSGs) in a co¬generation plant were found to have developed cracks that originated on the inside surfaces. The HRSGs receive hot exhaust gases from the primary Gas Turbines (GTs), which are fuelled with pipeline natural gas. The GTs was initially operating without any suppression of nitrogen oxides (NOx). After being in service for about two years, some of the cracks were found to have penetrated right through the 1/4 in. thick casings. The casings are fitted with insulation on the inside (hot gas side). Examination of steel samples cut from the casing walls revealed (i) fine cracks propagating through the steel from the inside surfaces, and (ii) the presence of relatively large amounts of nitrate ion on the inside surfaces. It was concluded that the nitrate ions originated from nitric acid that was condensing on the relatively cool walls of the casings behind the insulation. Nitric acid was formed in the GT exhaust gases by the combination of water vapour (formed from combustion of the hydrocarbon fuel and from moisture in the combustion air) and nitrogen oxides (formed from nitrogen and oxygen in the combustion air).

Jan 1, 2005

By P. D. Hanson, H. Colijin

"New procedures and techniques are now available for the design of bulk storage bins. These new methods have essentially eliminated guesswork in the gravity flow of bulk solids, and have provided a sound basis for the quantitative analysis of alternate designs of hoppers and bins. This paper will discuss the practical application of the Solids Flow Theory (Jenike & Johanson) and illustrate the required design procedure with a few examples of actual bin operations."

Jan 1, 1970

By Fernando Pajuelo Rincón

El presente trabajo describe la explotación del cuerpo mineralizado Barnabé en Huarón, donde es interceptado por una veta a través del uso de un equipo LHD neumático y del vehículo LHD -EH. No obstante, es válido mencionar algunas variantes aplicados al método del minado a partir de la estructura de la veta Rey, a fin de alcanzar una explotación selectiva y aumentar el valor de la tonelada del mineral. En ese sentido, las variantes aplicadas al método se dan en base a la flexibilidad del equipo de limpieza, reduciendo los costos de minado en los tajeos Barnabé y Rey.

Aug 26, 1988

By C R. Fountain, R J. Sinclair

The zinc industry is dominated by the electrolytic zinc (EZ) process. The EZ process has a low tolerance for impurities, resulting in tight concentrate specifications. Many mining companies sacrifice zinc recovery in order to meet smelter specifications. Some have ore-bodies that cannot be economically developed because too much metal has to be sacrificed, or it is just not possible to meet the specification. The BUKA Zinc Process (BZP) has been developed as a method of producing high-quality zinc from a wide range of concentrates. It can have lower capital and operating costs than the conventional zinc and lead production routes. Advantages accrue from increases in metal recovery during concentrating, smelting and refining; the elimination of most of the capital and operating costs associated with lead smelting; reduced transport costs; lower zinc refining costs; reduced refinery residue disposal costs; and reduced future environmental liabilities. This paper describes results of testwork that has been undertaken to demonstrate the viability of the BZP on both test rig and laboratory-bench scale.

Jan 1, 1998

By R. I. Jaffee, J. G. Dunleavy, W. Hodge, H. R. Ogden

Jan 1, 1949

By Robert Stefanko

The Federal Coal Mine Health and Safety Act of 1969 had far reaching effects upon many aspects of mining, ventilation being no exception. In this paper, good ventilation procedures are briefly reviewed, and attention is focused on the changes brought about by the new Act. By way of illustration the ventilation system for a typical Pittsburgh Block system is developed and the requirements of the fan determined. This is then solved by an available computer program, and the application is evaluated. Figure 1 represents a projected system for a coal property 1 by 3 miles in plan at a depth of 1000 feet with a coal thickness of 6 feet and desired daily tonnage of approximately 7200 tons on a two-shift basis. Only one half of the mine is shown (north area) with a mirror image mining arrangement to be developed concurrently for the south area. Six working units are projected, three in each area, one on pillar extraction, another developing panel entries and a third on main entry development. A two-split system is used for each working section so that the continuous miner and bolting crews each have a separate split of air, and no equipment need pass through a line brattice. The old requirement of 6000 cfm at the last open crosscut has been increased to 9000 cfm, and for the first time a minimum quantity (3000 cfm) is stipulated at the face thus requiring either line brattice or an auxiliary fan. With the respirable dust requirement limited to 3 mg/m3, the use of a blower system is precluded and exhaust systems are virtually the only choice. Maintaining the line brattice within 10 feet of the working face at all times as required by the new law has a definite effect on the mining cycle and is most difficult at best. In the highly gaseous Pittsburgh seam located in south-western Pennsylvania and northern West Virginia quantities of 20,000 cfm per split are not uncommon to maintain the methane percentage below the required l%

Jan 1, 1972

By B. P. Baruah

A good deposit of high sulphur coals of tertiary origin is existent in North eastern region of India. These coals are known to have indifferent characteristics in comparison to other Indian coals. The general Physico-chemical characteristics are low ash and high volatile matter, calorific value and sulphur content. Sulphur in these coals (70-95% of organic) is mostly affixed to the structure of the coal. Owing to the stringent environmental regulations, the utilization of these coals has severe limitations due to high sulphur content. In the present investigation, sulphur incorporation in to these coals has been discussed along with possible organic sulphur functionalities. The various desulphurization techniques carried out for removing sulphur from these coals have been discussed. Two step oxidative desulphurization processes has been found to be most efficient for organic sulphur removal along with mineral matter and potential toxic elements. Keywords: oxidative desulfurization, potential toxic elements, sulfur incorporation

Sep 1, 2012

By Joseph Cervik

This Bureau of Mines report deals with water infusion of coalbeds, which can control methane emission at face areas during developmental mining and which may sometimes suppress dust. Studies show that water infused into the coalbed flows through the fracture system and displaces the methane in the fractures and prevents migration from the solid coal. Displaced gas migrates away from the face area that has been water infused and enters the return ventilation airways. A gradual decrease in methane emission is observed from the start of infusion until the infused zone is mined through. Depending on the permeability of the coalbed, infusion pressures ranged from 300 to 2,200 lb/in2. Face emissions in the Upper Kittanning coalbed were reduced by 89 pet; reductions of 38 to 79 pet were measured in the Pittsburgh coalbed depending on the relationship between the face cleat direction and mining direction. Respirable dust levels were reduced by about 75 pct on a longwall section in the Pocahontas No.3 coalbed and by about 50 pct on a development section in the Upper Kittanning coalbed, but no statistically reliable reduction was found in the respirable dust levels in the Pittsburgh coalbed.

Jan 1, 1977

By José Darío Sanabria Cerrón

El presente texto describe la operación de las zarandas de alta frecuencia en la etapa de molienda de las operaciones mineras del país. Durante esta etapa se consume la mayor parte de energía que debe ser aprovechada eficientemente a través de una buena clasificaciónen húmedo de la molienda en minerales para disminuir los costos operativos sobre la base productiva de la planta.

Jul 1, 2015

By G. J. Biefer

"Fatigue and corrosion fatigue measurements were carried out on five commercially available metals -four steels and an aluminum alloy -which are used as structural materials in mine shaft conveyances. In the corrosion fatigue measurements, drain waters collected in the shafts of three different Canadian mines were used as corrodents. The mine waters had been selected on the basis of their relatively large differences in acidity and/ or composition.It was found that the corrosion fatigue strengths of the four steels were similar, despite their differences in tensile properties, and that the type of water used in the tests had little effect on the results. Mild steel showed the highest and most consistent values of the damage ratio (ratio between the corrosion fatigue and the plain fatigue strengths at 107 cycles). The corrosion fatigue behaviour of the aluminum alloy (ASTM Type 6061-T6) was found to differ markedly in the three mine waters. A high damage ratio (i.e., superior performance) was shown in a mine water in which the corrosion attack was uniform; much lower damage ratios were shown in waters which produced localized corrosion attack. Corrosion rates were too low to be deter-mined conveniently by conventional weight-loss methods, but calculations from polarization curves provided a rapid demonstration that corrosion rates were distinctly lower in the mine water which produced high damage ratios."

Jan 1, 1967

By S. G. Hardcastle

The effects of air velocity in promoting cooling through the evaporation of sweat generated when working at a high metabolic rate and/or in hot environments is well known. Many of the environmental heat stress indices consider the effect of air movement directly or indirectly within their determination, be it through the use of a specific instrument i.e. a wet-bulb globe temperature meter or Kata thermometer, or inclusion of in the calculation of a stress index, including the effective temperature, air cooling power, thermal working limit, ISO 7933?s predicted heat strain model. Within these models, ambient air temperature, relative humidity and barometric pressure are also considered in varying degrees to quantify an airstream?s capacity to evaporate sweat. Deep mine studies have shown cumulative increases in heat exhaustion rates with both decreasing air velocity and decreasing air cooling powers. However, despite a capacity to cool, the resultant cooling is very dependant on sweat production and its availability for evaporation; these are included where sweat rates and skin wettedness are considered. The first depends on hydration and physiological factors whereas the second is more an engineering factor related to the degree of clothing required. As sweat rates deteriorate with aging, the benefits of evaporative cooling potential can similarly be expected to be diminished. This paper continues to report upon on-going physiological studies exploring the potential for heat stress in deep underground mines through the simulation of mining activities in environmental chambers and a human calorimeter facility. The focus of this paper is to introduce preliminary data suggesting that increasing air velocity (0.5, 1.5 & 3.0 m/s) is beneficial for young subjects (22 ± 1 yrs), as indicated by lower core and skin temperature measures and heart rate during an intermittent work protocol, and then show a lesser benefit for older subjects (62 ± 2 yrs). Both subject groups performed the same task under the same environmental condition (35°C, 60% RH) wearing a standard mining ensemble. The study similar to others being performed under the Deep Mining Research Consortium funded research continues to provide evidence that a greater understanding of heat management processes is required and that worker education is critical as environmental measures and health and safety regulations may not be expected to include all demographic factors such as age, sex and health which are known to affect human thermoregulatory response.

Aug 1, 2013