Search Documents

Although Canadian bentonite is competitive in quality for most uses, it has not been accepted for the pelletizing of iron ore concentrates. In 1962, Canada consumed about 10,000 tons of imported bentonite for this use. By the end of 1965, the planned domestic consumption for this purpose alone will probably be more than 100,000 tons a year, valued at about $3 million. Consequently, a challenge exists for the establishment of a Canadian source of high-quality bentonite for pelletizing. Such a bentonite would also be suitable for the two other major applications -well drilling and foundry use. Brief mention is made of such topics as the identification, 1noperties, occurrences, exploration, applications, technology and laboratory testing of this clay. In particular, the type of bentonite in demand, the geological horizons warranting exploration, and simple preliminary test methods are discussed.

Jan 1, 1964

By S. S. Sephton, Kirit C. Vyas, Melvin J. Greaves

Energy requirements for various pelletizing systems are considered from a fuel and power aspect, with the presentation of typical energy heat balance flow sheets. A partial calculation for the firing zone of a straight grate system is shown and a comparison of an actual measured and a theoretical-calculated heat balance for a grate-kiln is presented. The power used for each pelletizing system and future possible energy savings a1•e also reviewed.

Jan 1, 1976

By L. G. Marshall

Gypsum mining and processing has been one of the principal industries in Iowa for more than 75 years. For most of that period, Iowa has ranked among the five leading States in the production of crude gypsum and of calcined-gypsum products. The Fort Dodge area accounted for 11 percent of the gypsum products produced in the United States in 1956. Before 1927 the output by the major companies came from underground operations, using a room-and-pillar stoping method. At present, all production comes from quarries. The quarry methods at the various properties are similar. This paper describes the quarrying, methods employed in the district and the type of equipment used by each company. The sections on history and geology are, in part abstracts from State annual reports and an Iowa Geological Survey publication.3/

Jan 1, 1959

By Charles W. Villiers

AS is well known, there are large and valuable deposits of coal in British Columbia, both on the mainland and on Vancouver island. These deposits are widely distributed over the Province. The chief sources of supply on the mainland are found in the Fernie and Princeton-Nicola districts and on Vancouver island in the Comox and Nanaimo districts. The coals range from a very high quality bituminous coal to lignite. On the Upper Skeena river there is said to be a very large deposit of anthracite or semi-anthracite, but this field has not been developed. Coal was first discovered in British Columbia on the north end of Vancouver island in the year 1835, but it was not until 1852 that coal mining was seriously undertaken by the Hudson's Bay Company at Nanaimo, where mining has been carried on continuously ever since that date. The production of coal in the Province continued to increase until the year 1910, when the annual output reached its peak at 3,100,000 tons and a total of 7,800 men were employed in the industry. Since 1910, the production has dropped steadily until, in 1934, only 1,347,000 tons of coal were produced and less than 3,000 men were employed. This continued decrease in production has in no way been caused by lack of coal reserves. It has been due entirely to curtailment of markets. I do not propose to discuss coal mining practice in British Columbia, where we have all sorts of mining conditions, including submarine mining. There is no lack of coal supplies for either industrial or domestic purposes, nor is there likely to be any shortage of coal in the Province for many generations. We have our mining troubles, which increase the cost of production, but there are no insuperable difficulties to prevent the extraction of a large and increasing supply of coal. Our main difficulty-in fact our only serious difficulty-is to find a market for our output, and we must consider means which can be evolved not only to conserve our existing markets but also to expand them, at any rate within the boundaries of Canada. I will therefore confine my remarks chiefly to the all-important factor of Markets for our coal.

Jan 1, 1936

By Jerome F. Sheldon

The earliest recorded history in the use of belt conveyors in the United States is in O. Evans' "Miller's Guide" published in Philadelphia in 1795. Evans defines a conveyor as a "broad endless strap of thin pliant leather or canvas revolving over two pulleys in a case or trough." (Ref. 1) In this definition, pulleys are being used in a bulk material belt conveyor application. Pulleys used in belt drives can trace their origin back to 1200 A.D. In fact, Engineers had considerable experience designing them into drives transmitting greater horsepower than those used in the early belt conveyors. In belt conveyor application, a pulley's purpose is primarily three-fold, 1) support the belt in directional changes, as designed in the conveyor, 2) transmit driving power to the belt, and 3) guide or train the belt. There are various types of pulleys used in belt conveyor systems and these are thoroughly covered in "Belt Conveyors For Bulk Materials" prepared by CEMA, 1966. For our discussion, however, the most common used in belt conveyors are drive pulleys, snub pulleys, head pulleys, tail pulleys, takeup pulleys and bend pulleys. The drive pulley imparts the driving force to the belt and may be located at the head or discharge end of the conveyor, in return strand, or at the tailor loading end of the conveyor. A snub pulley is located near the drive pulley to provide more arc of contact between the belt and pulley for maximum

Jan 1, 1971

Arsenic occurs naturally in rocks and soils, water, air, plants and animals. It can be further released into the environment through natural activities such as volcanic action, erosion of rocks and through human actions. Higher levels of arsenic tend to be found more in ground water sources than in surface water sources of drinking water. Compared to the rest of USA, western states have more systems with arsenic levels greater than 10 parts per billion (ppb). The US Environmental Protection Agency (EPA) has historically regulated arsenic in drinking water at 50 ppb, but the agency has lowered the maximum contaminant level (MCL) for arsenic to 10 ppb-to be in compliance by January 2006.This paper reviews briefly a) aqueous arsenic chemistry and removal mechanisms and b) the available treatment processes to attain the drinking water standard of 10 ppb by 2006. The combining of an appropriate removal method with an existing system depends on several factors such as nature of arsenic, the water source, existing plant equipment and processes site conditions etc. The paper also includes one or two case studies from the State of Arizona. Key words: Arsenic, Drinking water, Treatment Technologies

Jan 1, 2005

By Forrest T. Moyer

Quarry accidents in 1963 caused 61 fatal and 3,468 nonfatal injuries which occurred at respective frequency rates of 0.31 and 17.91 per million man-hours of worktime. The fatality record in 1963 was better than in 1962 but was appreciably worse than in 1.961. For nonfatal injuries, the 1963 record was slightly worse than in 1962 but was better than in 1961. The injury--severity rate of 2,913 days lost or charged per million man-hours in 1963 was better than that of 3,046 in 1962, the first year for which such data became available. The average severity of all injuries in 1963 was 160 days lost or charged per injury, 15 less than in 1962. An average of 91,960 men were at work on active days in 1963 and these men had an aggregate worktime of 193.7 million man-hours during the year.

Jan 1, 1972

By S. Qian

Galvanic corrosion is a potentially major concern associated with the application of stainless steel reinforcement which is in direct (electrical) contact with carbon steel reinforcement in concrete structures. Judicious use of stainless steel rebar in both new construction and rehabilitation of older structures is a viable, cost-effective option for extending service life and reducing maintenance costs. Questions, however, had arisen about the possibility of increased corrosion due to galvanic effects. This paper investigates the galvanic-coupling behaviours of three different types of stainless steel and carbon steel. Tests were performed both in electrochemical cells and with specimens in concrete inside an environmental chamber. The results show that oxygen reduction on stainless steel is the rate-determining factor for galvanic coupling of these two metals. It is much lower than that of passive carbon steel. As a result, the galvanic coupling of stainless steel with carbon steel will not increase the risk of corrosion of carbon steel reinforcement.

Jan 1, 2005

By S. Doombos

To convert the railway-bridge across the Oude Maas between Dordrecht and Zwijndrecht into a vertical lifting bridge, a drastic adaptation of the existing piers is necessary. Extra piles have to be placed quite close to the present piers to bear the extra weight of lift-towers and bridge-sections. This article describes the special technology applied to drive steel tubular piles l800 mm. in diameter and 36 m. in length vibration-free into position. At the same time a method of pile-point-reinforcement has been applied to minimize the settlements.

Jan 1, 1989

By M. Sears, K. Mohamed, J. Addis, J. Wickline, G. Rashed

To better understand the load shedding and the stress transfer on coal pillars due to room-and- pillar retreat mining in deep cover panels, researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted a monitoring field study. Two sites, at overburden depths of 1,000 ft (304.8 m) and 1,500 ft (457.3 m), were selected in a room-and-pillar mine operating in Southern West Virginia. The deformation and stress changes in the roof and two adjacent pillars at each site were monitored during the retreat mining process. The monitoring results and field observations were used to calibrate large-scale FLAC3D models for each site. The calibrated models were used to assess different sizes of roof bolts installed in deep cover areas. INTRODUCTION Deep cover room-and-pillar retreat mining is an important emerging issue that will intensify in the future as shallower reserves are depleted (Mark, 2009; Chase et al., 2002). During pillar retreat mining, the likelihood of local and/or global instabilities increases due to elevated stress levels near the pillar line because of the abutment loading. In the last decade, approximately 31% of the room-and-pillar mining groundfall fatalities in the United States occurred during pillar retreat mining. Between 2013 and 2017, this proportion increased to 55%, of which 50% of these fatalities were due to falls of roof and rib that occurred during pillar recovery (MSHA, 2018). One interesting piece of information about pillar recovery fatalities was that the victim was nearly always under bolted roof. Sheared and broken #5 (5/8-in), fully grouted rebar bolt failure contributed to three of four fatal roof fall incidents that have occurred in deep cover retreat mines (NIOSH, 2010). This claim raised the following question at the study mine: Is it safe to use a 4-ft long #5 (5/8-in) rebar bolt grade 60 at a depth of cover more than 1,000 ft (304.8 m)? There was some concern about shear failure of the #5 (5/8-in) rebar bolt at a depth of cover over 1,000 ft (304.8 m). To answer the question and to reduce accidents and fatalities caused by ground falls due to room-and-pillar retreat mining in deep cover panels, the National Institute for Occupational Safety and Health (NIOSH) monitored the roof and rib deformation and the change in vertical pressure within two adjacent pillars during pillar recovery. The study was conducted at two deep cover sites in a room-and-pillar mine located in Southern West Virginia that operates in the Lower War Eagle (LWE) seam. The monitored sites were selected at 1,000 ft (304.8 m) and 1,500 ft (457.3 m) depths of cover. In this paper, site-1 represents the monitored site at 1,000 ft (304.8 m) of cover, while site-2 represents the monitored site at 1,500 ft (457.3 m) of cover. For this study, large-scale FLAC3D numerical models were calibrated based on both field observations and instrumentation results. The calibrated models were then used to compare the ground response and the induced stresses of two pillars at instrumented sites 1 and 2. The maximum lateral displacement (roof shift) obtained from the calibrated large-scale FLAC3D models was applied to a small-scale FLAC3D bolted models, the safety factor for axial stresses of the simulated roof bolts was calculated at the deep cover sites.

Jan 1, 2019

By J. D. Miller

"It is now possible to use 3D X-ray tomography analysis for plant-site characterization of coarse particles at a sampling rate of about 3 kg/min for particles which range in size from 150 mm to 1 mm at a voxel resolution of about 150 microns. This is quite a significant advance in X-ray tomography technology and should be useful for plant-site coarse particle characterization (size, shape, composition, density, texture, grain exposure, mineral liberation) with a response time of minutes after receiving the sample. Applications in the mineral industries are discussed including the coal industry, aggregate industry, metal mining and the processing of industrial minerals. INTRODUCTION Plant-site characterization of coarse particles at coal preparation plants, crushed stone/aggregate plants, and mineral processing plants is needed to improve plant capacity, product quality, and/or process efficiency. Not much on-line coarse particle characterization is done at these plants. Some limited information regarding particle size is obtained on-line from reflected light images using systems such as the OPSA, Split, and WipFrag analyzers. Even laboratory analysis of coarse particles has been difficult because of the large amount of sample required to insure statistical significance of the results. During the past decades laboratory 3D characterization of particles from energy and mineral resources by X-ray tomography has been demonstrated and used to good advantage [1, 2]. 3D X-ray tomographic analysis had its origin in the medical services industry; it is used to provide internal images of the human body and now has also been developed for non-medical applications [3]. Figure 1 shows a schematic diagram for the cone-beam geometry micro-CT system. In our case X-rays from a microfocus X-ray generator are partially attenuated by the sample (a packed bed of particles) that is made to rotate in equal steps in a full circle about a single axis of the particle sample. At each rotational position, the surviving X-ray photons are detected by a planar two-dimensional array (image intensifier) large enough to contain the shadow of the specimen. These two dimensional projection images are collected using conventional video technology. The video signal for each projection is then converted to a two-dimensional digital array by an image processing system. Finally, a three-dimensional image is reconstructed from the collected set of projection images. With the availability of automated high speed X-ray tomography [4] it now seems possible to do plant-site particle characterization at a sampling rate of about 3 kg/min for particles which range in size from 150 mm to 1 mm at a voxel resolution of about 150 microns. This is quite a significant advance in X-ray tomography technology and should be useful for plant-site particle characterization (size, shape, composition, density, texture, grain exposure, mineral liberation) with a response time of minutes after receiving the sample. Applications in the mineral industries are discussed including the coal industry, aggregate industry, metal mining, and the processing of industrial minerals"

Jan 1, 2016

By A. B. Hooker, L. C. IlsLey

"Observation of the use of trailing cables in ""mines shows that the chief limiting factor in the life of the cables and their safe use is the smashing or crushing of the cables in service, together with the effects of consequent splicing.Trailing cables are crushed when run over by cars, mining machines; and locomotives or when hit by falls of roof. Crushing damages the insulation and may cause failure at once or in later use. Failure may be either by short circuit between the conductors or by grounding to the track. The failure of a live cable causes electric arcs capable of igniting explosive mixtures of methane and air. Every cable failure in a gassy or dusty mine is, therefore, a real or potential hazard.Some mine operators do not allow the splicing of trailing cables for use in gassy mines, bet require that a damaged cable be immediately replaced and if repaired that it be used only in nongassy mines. Other operators allow the making of temporary splices to permit completion of the shift but require that such splices be remade and vulcanized before the cable is used again.Still other operators allow the continued use of temporary splices, which in general means that a cable is used until the splices give trouble in reeling, or overheat, or pull apart. Then the spliced sections are either cut out or the whole cable is replaced.Splices often determine the useful life of a cable. A splice poorly made may pull apart ueder mechanical strain and cause arcing that burn* the surrounding cable or ignites as or coal-dust. If it has lower conductivity a splice is the first part of the cable to heat; it may become so hot under load that it will burn apart and damage other parts of the cable, or, if it be a soldered splice, the solder may melt and allow parting of the cable. A poorly made splice often has insufficient insulation which may alloy short-circuiting between conductors or permit external contacts capable of giving an electric shock to one handling the cable. The splice is sometimes bulky from too much insulation and takes up too much room on the reel, causing uneven reeling; also by catching on the spooling device the oversized splice may receive expressive pulls and wear. Splicing is therefore a very important factor in the use of trailing cables."

Mar 1, 1932

By L. D. Anderson

IN STUDYING Utah as a lead producing state one is immediately confronted by the fact that few, if any, of the ores of the state are valued for their lead contents alone. More correctly the ores from which this metal is recovered are characterized as silver lead. Even then the whole story is not told for many of these ores carry also gold, copper, zinc, bismuth, antimony, arsenic, tellurium, and other metals. It becomes apparent, therefore, that the production of lead i11 Utah is influenced by many factors. For example, i11 the early part of 1923 there was a marked increase in the production of the lead by reason of the efforts made by silver mines to produce as much silver as possible before the termination of purchases under the Pittinan Act in June, 1923. As nearly all silver ores carried more or less lead the production of that metal was increased with the increase in silver production. Very few, if any, ores of the State are mined for their lead contents alone. Important as Utah's contribution to the lead output of the country is nevertheless it is bound up to some extent with the production of gold, silver and copper.

Jan 1, 1925

Rapidly identify unstable mine waste embankments and similar dam structures. Approach Aerial photography, geotechnical instrumentation, and telephone or satellite data transmission are used to supplement walk-around inspect ions. How It Works Embankment stability and other indicators of structural integrity are evaluated using aerial photography, and on-site unattended instruments and data transmitting systems. Evidence of external movement and water seepage is obtained from aerial photography and photogrammetric evaluation techniques. Surface points marked by stake- mounted targets are monitored photographically at time intervals of several weeks or months. Photographic measurements of x, y, and z coordinates of these points are obtained from flying a series of photo-runs over the dam.

Jan 1, 1979

By L. Ozdemir

An investigation was made to determine the mechanical properties of oil shale at elevated temperatures and confining pressures, the thermal properties at elevated temperatures, and to provide mathematical models for mine design for in situ oil shale retorting. A review of current activity in in situ retorting is included with a comprehensive list of references. Tests were run at temperatures from 20°C to 500°C and confining pressures to 1500 psi with shale of 10 to 30 gallons per ton. A major loss of strength occured in heating 140°C with a partial regain from 380°C to 500°C. Higher grade shale had lower compressive strength. Elastic properties showed large variations. Brazilian tensile strength showed a similar temperature sensitivity as the compressive strength. Equations were developed for each property in terms of grade, temperature and pressure. Thermal, electrical and acoustical properties showed anomalies through the temperature range. Creep is a major factor in overall deformation of heated shale. Oil shale was found to be an excellent insulator. Loss of pillar support area at 800 hours of heating would be about 10 percent. Good correlation was found between a finite element model using the developed properties and an in situ heater test.

Jan 1, 1981

By G. L. Oldright

In the previous study that has been made by the authors on smelting in the lead blast furnace, the furnace examined was one that operated under conditions that have been considered as more or less normal up to the present time. That is although the furnace had in its charge a large portion of sinter, it also handled considerable quantities of naturally oxidized direct-smelting ore. Other ingredients, such as the limestone, were also added as fairly coarse material. The charges contained only about 24 per cent of lead. Until the changes incident to modern flotation began to take effect, many lead plants doing semicustom smelting in districts where competition was keen and much of the bonanza ore was exhausted were faced with the difficulty of obtaining enough lead to get a sufficient "lead fall" in the blast furnaces to clean the slag thoroughly and to separate it from the lead. A charge containing 24 per cent of lead would have been considered a very rich one by such smelters.

Jan 1, 1931

By G. L. Oldright

In the previous study that has been made by the authors on smelting in the lead blast furnace,4 the furnace examined was one that operated under conditions that have been considered as more or less normal up to the present time. That is, although the furnace had in its charge a large portion of sinter, it also handled considerable quantities of naturally oxidized direct-smelting ore. Other ingredients, such as the limestone, were also added as fairly coarse material. The charges contained only about 24 per cent of lead. Until the changes incident to modern flotation began to take effect, many lead plants doing semicustom smelting in districts where competition was keen and much of the bonanza ore was exhausted were faced with the difficulty of obtaining enough lead to get a sufficient "lead fall" in the blast furnaces to clean the slag thoroughly and to separate it from the lead. A charge containing 24 per cent of lead would have been considered a very rich one by such smelters.

Jan 1, 1931

By D. J. Buchanan

British Coal's mining research programme is directed towards the strategic objectives of reducing production costs, improving product quality and resolving health, safety and environmental issues. The strategy for R&D is described and selected parts of the programme are reviewed. Two major initiatives are directed towards reducing production costs: geotechnics and automation. Integrated exploration techniques are used to delineate geological structures as an aid to mine planning. Rockbolting is being rapidly introduced and the in situ stress field has been found to be of significant influence. Automation is the subject of a major programme. A strategy for coal quality has been devised. The health, safety and environmental programme concentrates on the traditional hazards together with surface environmental problems.

Jan 12, 1992

By G Brudek, P Elestedt

Schalker Eisenhütte und Maschinenfabrik GmbH, Nordic Minesteel Technologies and Bombardier Transportation have developed an evaluation tool that considers the main cost drivers of the rail, truck and conveyor haulage systems on the market today. In almost every circumstance, the advantages of a haulage solution are clear. A haulage system is outlined that is fully automated, including driverless operation, and that provides increased tonnage, safety and equipment life and reduced maintenance downtime. The haulage system has been implemented by a number of companies, including Codelco, LKAB and Freeport’s Grasberg mine. CITATION:Brudek, G, Elliott, R P and Elestedt, P, 2016. Moving mORE for less, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 535–542 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By David Smith, Bernie Martin

The Queens Bored Tunnels consist of 11,000 feet of 19'-6" inside diameter tunnels mined through rock, mixed face and dense glacial till, constructed with bolted gasketed one pass reinforced concrete liner. The tunnels are to be excavated with a pressurized face TBM, either EPB or slurry. The construction of the tunnels will require ground stabilization in the mixed face area, instrumentation and monitoring of railway infrastructure, underpinning of bridges, relocation and protection of utilities, demolition of some industrial buildings, construction of open-cut approach tunnels and emergency exits and vent plants. The purpose of this paper is to describe the scope of work, the suggested methodology and the proposed construction schedule.

Jan 1, 2005