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By S. J. Schatzel, K. M. Ajayi, Z. Khademian

The integrity of unconventional shale gas well casings positioned in the abutment pillar of a longwall mine could be jeopardized by longwall-induced deformations. Under such scenarios, the surrounding fracture networks could provide pathways for gas flow into the mine creating safety concerns. To provide recommendations for developing guidelines that ensure a safe co-existence of longwall mining and unconventional shale gas production, this study evaluates the impact of parameters that could affect potential shale gas flow into the mine in the event of a casing breach using a discrete fracture network (DFN) model. These parameters are evaluated using a conceptualized DFN realization that is representative of the fractured zone in the overburden, and the range of parameter variations are within values validated with field measurements. The results show that a decrease in fracture aperture (potentially due to longwall-induced stress in the likely vicinity of the breach location) reduces the potential gas flow to the mine by a significantly higher proportion. A 50% decrease in the aperture of the fracture that directly transports the gas from the casing breach location reduces the gas flow to the mine by over 70%. Similarly, changes in the fracture water saturation level significantly affect the gas flow. In all cases, the potential gas flow to the mine is higher if the casing breach occurs at an increased gas well pressure. These findings provide critical information regarding the impact of each of the parameters associated with gas flow in the event of a shale gas casing breach near a longwall mine and could help towards the development of guidelines to ensure a safe coexistence of both industries.

Mar 2, 2022

By H. N. Thomson

(Butte Meeting, August, 1913.) GENERAL. THE Tooele plant. off the International Smelting & Refining Co. is situated at the mouth of Pine canyon, Tooele county, Utah. It is connected with the main line of the San Pedro, Los Angeles & Salt Lake railroad by the Tooele Valley. railway, and is about 7 miles from Tooele Junction. Fig,. 1 is a general view of the plant. The copper plant has been in operation since July, 1910, and the first blast furnace it the lead plant was blown in on Feb. 29, 1912. The location of the plant was selected on sloping ground with the idea of using gravity to the fullest extent and thus keeping labor at a minimum. Practically the entire plant is constructed of steel, reinforced concrete, and. brick.

Jan 7, 1913

By D. W. Park

Geologic condition is one of the most important factors for longwall mining operations, especially, the existence of faults limits the mineable area, or cause stress variations at the longwall face. Recently, a longwall panel passed through a fault at the Shoal Creek Mine of Drummond Company, Inc. The fault was situated diagonally along the longwall face and the coal seam was displaced up to 2.4 m (8.0 ft) in a mode of a normal fault. LoSCoMS (Longwall Strata Control and Maintenance System) was used for monitoring shield pressure every minute and interpreting data in terms of setting, developing and final pressures. The results of the analysis regarding the influence of the fault on the shield pressure are presented.

Jan 1, 1999

By S Brown

With oxygen conditioning routinely used in both the lead and zinc circuits at Pasminco Elura Mine a more sophisticated method of determining oxygen demand was required. It is known that different ore types have different oxygen consumption rates, however oxygen is added at a fixed rate regardless of ore type in the plant. Therefore, a simple laboratory test was devised to measure the oxygen demand of ores. The paper describes the technique employed, and provides an interpretation of the results. These data, together with pulp chemical measurements (Eh, pH and EDTA extraction data) were correlated against laboratory flotation performance to establish the relationship between oxygen demand and the position of the grade/recovery curve.

Jan 1, 2000

Two key elements in the design of a pastefill or high density backfill system are the preparation of the backfill material and its distribution underground. This paper examines these two areas. Owing to the essentially impervious nature of total mill tailings, preparation of pastefill and high density fill from current tailings involves a physical dewatering process. There are currently three methods available for this process: Vacuum or pressure filters. These represent the ætraditionalÆ approach to the preparation of pastefill. Paste production storage mechanism. This is a thickening/storage mechanism developed with the specific objective of producingpaste/high density backfills. Fluidization. This system utilises silos fitted with simple dewatering devices and nozzles. Recently developed by CANMET, it provides the simplest and most economical approach.This paper describes and compares the three preparation methods, from a practical and an economic point of view. Once the pastefill/high density fill has been prepared and binder added, the backfill must be distributed underground into the stopes. A fundamental factor in the design of a distribution system is the rheology of the material. No two materials will exhibit the same properties, and a sequence of rheological and related testing is required prior to the completion of the design of the underground distribution system. This paper covers the testwork normally required and discusses the fundamental design parameters of pastefill distribution systems. The final section of this paper summarises the use of pastefill at three mines in Canada.

Jan 1, 1998

By G. S. Hume

THE Plains of east-central Alberta herein described embrace an area from Viking east to the Saskatchewan boundary and from North Saskatchewan river south to Coronation and Monitor (Figure 1). By far the greater part of this area is deeply drift-covered, and .outcrops of bedrock are relatively few and often widely separated. Within the area there are large morainal hills and others of considerable extent that superficially have all the characters of morainal hills but contain a core of bedrock. These latter, then, were hills when the ice sheet traversed the country and only have been modified by glacial agencies. In many places on them, the drift is but a thin veneer, as is certainly the case in part of the Neutral hills (Figure 2) northeast of Coronation and north of Monitor. In other cases, however, as in the Blackfoot hills, southwest of Lloydminster, the drift is sufficiently thick to conceal practically all the bedrock and in many places no information is available as to whether a bedrock core, representing a pre-glacial hill, is present. There is no question, however, that the larger river valleys, as for example those of the North Saskatchewan and Battle rivers, are in part at least pre-glacial. Proof of this can be demonstrated in many places, because obviously the valleys must have been present in pre-glacial times to allow glacial deposits to have accumulated in them. It is also known that inter-glacial deposits occur. At one locality in Battle River valley, in sec. 30, tp. 45, range 2, west of the 4th mer., the following section occurs( l ): 15 feet of boulder clay with granite and other boulders. 56 feet of stratified sands, clays, and gravels containing pebbles of Precambrian rocks and fresh-water shells. From this it is apparent that the 56 feet of stratified sands, clays, and gravels must have derived their Precambrian pebbles from a previous glaciation of which the overlying boulder clay represents another ice advance in this area. Thus, although the river valleys contain glacial and interglacial deposits, they have not been filled by them to such an extent that the drainage has been diverted, and in many places, especially in the case of Battle river and some smaller streams, the size of the valley is altogether out of proportion to the size of the stream it now contains.

Jan 1, 1937

By G. R. Palmer

The success of future electric vehicles will depend greatly upon the power supply choices made today. Research is presently being conducted by automotive engineers and electrochemists to determine what battery type may be the most promising. Not only are product production and application efficiencies being evaluated but also environmental concerns of reclamation and recycling. Rechargeable batteries using nickel-metal hydride electrodes are strong candidates for these electric vehicle applications. The U.S. Bureau of Mines is investigating hydrometallurgical technology that separates and recovers purified metallic components present in nickel-metal hydride battery scrap. Sulfuric, hydrochloric, and nitric acids are all capable of dissolving the battery electrode alloys given the proper operating conditions. Solvent extraction of the leach solutions using D2EHPA removes iron, and selective precipitation shows promise of recovering the other metals in the H2SO4 and HNO, systems.

Jan 1, 1994

By S. Marsland

Reference materials have always been important for validating and controlling analytical methods. They have recently become even more important as quality requirements have become more stringent and customer demands for properly verified and controlled results increase. Clients, especially from the resource exploration industry, demand critical validation of all results reported. Mintek has been producing geological and semi-processed ore references since the early 1970s and recently, due to increase in demand, other manufactures have entered the South African market. This paper describes analytical challenges from the customers? perspective, the customers being metallurgists, mine geologists, environmental scientists and geologists from resource companies. Reference materials with their appropriate use and a good understanding, can aid greatly in building confidence in the results, choosing the right laboratory for a project, deciding which set of results is correct and providing evidence to the customers? clients that the best possible results have been obtained

Jan 1, 2007

By H. A. Wilson

Introduction Salt (sodium chloride) occurs naturally either in the solid state as rock salt or in solution as a component of natural brines. It is the major saline constituent of sea water, which contains about 4 percent salt-roughly 164 million tons, or enough to meet world salt demands for five years, per cubic mile. The great rock salt deposits of the world are generally regarded as having been formed by the evaporation of sea water over long periods of rime in wholly, partially, or periodically cut-off bays of ancient oceans. History and Occurrence of Salt in Canada We can speak today of the vastness of Canada's salt resources, but it was not always so. Settlement of our Atlantic seaboard and the Sr. Lawrence valley began in earnest in the early 1600's. The first small commercial salt works in Canada did not come into operation until 1866. Thus, for some two and a half centuries, the inhabitants of this growing country were entirely dependent on foreign sources for every pound of salt they consumed. The record shows that from at !east 1800 onward, the need for a domestic salt industry was clearly recognized by the governments of the day. It was during the Western Ontario oil-boom of 1866 that the initial discovery of rock salt in Canada was made, not far from Goderich, at a depth of 1,000 feet. A salt company was promptly organized, and with their operations there began the gradual and still uncompleted conquest of the Canadian salt market by the Canadian salt industry. Over the next thirty years many holes were drilled into the Salina formation both in Ontario and Michigan, and encountered rock salt. A vast salt-basin was disclosed, approximately outlined, and given the name Ontario-Michigan Salt Basin. The Ontario portion of the basin extends over at least 3,500 square miles, is met with at a depth varying between 800 and 1,600 feet, and has a thickness of 50 to 250 feet. No attempt has ever been made, so far as we know, to calculate the total salt reserves of this basin, but the minimum indicated in the Ontario portion by the figures just cited is just under thirty-five cubic miles. The specific gravity of rock salt is 2.2. From these data, those so inclined may calculate the tonnage.

Jan 1, 1947

By C. M. White

CITIZENSHIP is a rather abstract subject on which a great deal could be said-a subject on which a great deal is said -and still one which too many of us seldom think about and seldom work at. Too many of us engineers and business men have but a vague idea of citizenship. We think that if we go to the polls on election day and obey the laws scrupulously, with the exception of an occasional traffic violation, we are pretty good citizens and are doing our duty by our city, state, and nation. But when you think it over, that's a very passive observance of the important right of counting oneself a citizen of a country. There is nothing very positive in that attitude. There is nothing that indicates that we have sufficient interest to really go out and do a job for the -welfare of our country, forgetting any personal advantages or inconveniences that might arise. In other words, this type of voting-on-election- day, law-abiding citizenship does not keep us awake a single minute; it does not take any particular thought or require the expenditure of any time or energy.

Jan 1, 1939

By D. A. Dukelow, K. Li, G. C. Smith

Decarburization in the Fe-C system by oxygen top blowing has been studied in laboratory -scale experiments. It is shown that equilibrium models fail to explain or predict either the course of refining or endpoint conditions, giving results which either are incompatible with the chemistry of the system or do not satisfy material balance requirements. Also the path of decarburization was found to vary even for heats made under apparently identica1 conditions. A promising approach to analyzing the decarburization results is to relate oxygen efficiency fm carbon removal to bath carbon content. This relationship for Fe-C heats shows the same range of oxygen efficiencies as is obtained in pilot-plant and commercial heats using hot metal-scrap charges. This implies that oxygen transfer is primarily controlled by the decarburization reaction itself, independent of other refining reactions. Therefore, it should be possible to study separately decarburization and slag-metal reactions. DECARBURIZATION is probably the most important reaction in steelmaking. Not only is it a main reaction in the refining of iron to steel but it also provides the stirring action in the bath necessary for the diffusion processes to proceed at reasonable rates so as to make a steelmaking process practical. Kinetics of decarburization in the open-hearth process has been a subject of investigation for many years.&apos;-B It is generally accepted that at steelmaking temperatures the rate of homogeneous C-0 reaction is extremely high and cannot constitute a rate-controlling step. Diffusion of oxygen through a boundary film in the metal phase has been suggested by arken&apos; as rate-determining. Recently, Larsen and sordah16 concluded from experiments in a laboratory furnace that, with oxygen supplied from air or combustion gases, the rate of "steady-state" carbon boil is controlled essentially by a diffusion process of O2, Co2, or H2O through a film of nitrogen above the slag surface. Displacing this diffusion film by a stream of nearly pure oxygen produced a ten-fold increase in the rate of carbon boil with the rates of slag-metal oxygen transfer, bubble nucle-ation, and other steps all apparently able to keep pace. In the top-blown basic oxygen process, however, the transport of oxygen takes a more direct route. and the state of bath agitation is much more turbulent than in the open-hearth process. In addition, direct contact of the gas with the metal phase provides opportunity for direct oxidation of carbon. It is likely that the rate-limiting factor for the decarburization reaction will be different. However, only a few descriptive discussions of the subject have been reported in the literature.10-l2 Studies of the decarburization kinetics based on plant or pilot-plant data are necessarily complicated and are influenced by other refining reactions which occur simultaneously. In order to investigate the mechanism of decarburization, experiments have been conducted in which carbon-saturated iron melts were top-blown with pure oxygen over a range of conditions. It is hoped that this study will form a foundation on which a more basic understanding of this important reaction may be built. EXPERIMENTS One group of blowing experiments was made in a standard 200-lb induction furnace and another group in a 500-lb induction furnace. The furnaces were modified to the general shape of a basic oxygen furnace by adding a rammed refractory cone section to the regular crucible body. Crucible and cone were of high MgO (95 pct) material. A water-cooled lance, 1/2 in. in diam and threaded at one end to take a nozzle, was used for blowing oxygen. The lance with its water and oxygen lines was supported on a cantilever arrangement so that it could be moved up, down, or sideways. Oxygen of 99.5 pct purity was supplied from a cylinder and metered through a rotameter equipped with pressure and temperature gages. Another pressure gage was located at the top of the lance. A schematic diagram of the assembly is shown in Fig. 1. Before each experiment, a weighed amount of ingot iron, containing 0.02 pct C, < 0.01 pct Si, 0.10 pct Mn, 0.019 pct P, and 0.015 pct S, was charged in the furnace and melted down by induction heating. Graphite was then added to the molten charge until it became saturated. When the temperature of the charge reached the desired level, the lance was lowered to a predetermined height above the bath

Jan 1, 1964

By Ali Porbaha

In today&apos;s fast-track construction environment, owners are searching for non-conventional technologies to build their projects faster and safer while maintaining traffic flow during construction. To that end designers and contractors are providing solutions that incorporate many unique features to expedite construction processes. In addition to timely delivery of the finished highway products, there is an increasing interest in making the initial investment in applying innovative technologies and thereby minimizing costly maintenance of highway projects. Accordingly, the aim of this paper (along with the accompanying paper) is to examine innovative technologies, developed mostly in Europe, that accelerate construction of highway, runway and railway embankment foundations. For each technology, a basic concept, installation technique(s), and design considerations are discussed, along with the case history of a real-world project. The Geotextile Encased Columns (GEC), AuGeo, and Continuous Flight Auger (CFA) are presented in Part I. Deep Mixing (DM), Mass stabilization, Cut-Mix-Injection (FMI), and Combined soil Stabilization with Vertical columns (CSV) technologies are discussed in Part II.

Jan 1, 2002

By Alfred Wild

The Kraftile Co. plant, Fremont, Alameda County, Calif.--the largest producer of glazed, structural wall units west of the Rocky Mountains-- maintains modern processing facilities to evaluate and blend a wide variety of clays from several sources to produce quality products. The report desribes the prospecting, exploration, and test methods used to locate raw material sources and covers processing methods, cost factors, and trends. Also, the geologic and ceramic factors are considered in a general discussion of the economics, potentials, and requirements of clays as raw materials for ceramic tile manufacturing.

Jan 1, 1963

By Paul L. Bearden

The accumulation, handling, and utilization of sludges formed from wet process phosphoric acid is one of the major problems in the industry. The purpose of this paper is to explain some of the considerations and techniques that can be employed to provide some measure of control over the problem. An acid made from a Central Florida phosphate rock is used to illustrate the effects of one process design approach used to provide one type of control. Other approaches or techniques are discussed on a general basis. In every case, the discussion is purposely limited to conventional dihydrate processing in which phosphoric acid is produced from the filter at a strength of approximately 30% P205 and is subsequently concentrated to higher strengths such as 44 and 54% P205.

Jan 1, 1966

By R. Heersink, C. H. Wells

Innovations in communications and real-time information systems are providing industry opportunities to improve profitability. Real-time operating data is collected from equipment across a site or even several sites into a central server for secure PC and PDA-based Internet access. This paper includes discussion of how operating staff can use wireless devices to see equipment and processing data from anywhere throughout the mines and concentrators, and how management can view results from multiple mines, all in real time. Additional opportunities enabled through the remote access by equipment vendors or mining consultants is also presented, as well as an overview of typical benefits and current installations.

Jan 1, 2002

By A. B. Hildebrandt

P. B. Baxendell is to be complimented for an exccllent piece of work. To our knowledge there has been no previous publication of field data on the flow of oil and gas through the annulus of a well. It is certainly gratifying to see this work on annular flow confirm the previous published correlation procedure on tubing flow. It extends considerably the range under which reliable gas-lift calculations can be made. Baxendell discussed this work with us about a year ago and was kind enough to send a large scale plot of his correlation. We had been designing gas-lift installations on flow through the annulus, assuming that the original correlation of the f factor based on tubing flow&apos; was valid as long as we stayed within the same mass velocity range on which the correlation was based. Doing this work necessitated the use of an equivalent diameter for the annular flow. The equivalent diameter is defined as area&apos; of stream cross section wetted perimeter and for the case of an annulus is D, — D,. Substituting this in the basic equation correlating energy loss along with the area to flow required to convert the velocity, to volumetric flow rate, D (Baxendell&apos;s Eq. 7) becomes dell&apos;s expression, D,). Similarly, the D in 1.4737 X 10 (M&/D) becomes (D, + D;) for annular flow. On receipt of Baxendell&apos;s data, we. of course, recalculated it to put it into the form we were using, and to see how well it agreed with the correlation based on tubing flow. Fig. 1 shows the results, which were certainly gratifying. For low values of (D, - D,) pv, the data coincide with the data on flow through tubing, whereas at high values the data on flow through the annuli appear to be leveling off to a constant value. For very high rates of flow where the turbulence is very high, one might expect the value f to level out and become constant. A bulletin published in 1914 by the U. of Wisconsin presented results of a large number of laboratory teats in air lifting water through short lengths of 1.25-in. tubing. It was possible to correlate a random sampling of

By Bruce R. Sutherland, Jim B. Ramsden, Gerry L. Bolton

Conductive metal powders are important building blocks for today&apos;s micro-electronic circuitry. Formulated into inks, they provide the interconnects needed to complete a complex integrated circuit and the means to enter the world of miniaturization. Traditionally, the inks have been based upon expensive metals such as silver, palladium, platinum and gold because of their excellent electrical conductivity and resistance to corrosion and oxidation. The use of a copper based ink, as an alternative to precious metal inks, recently has received considerable attention. Instability in the prices and limited supply of certain precious metal systems have driven up production costs, making the development of a lower cost copper system more attractive to manufacturers. However, lower production costs are on1 y real ized if performance and reliability can be maintained. While the development has been driven by cost, copper does offer some significant performance advantages over noble metal systems: conductivity as good as silver and 4W better than gold; leach resistance better than silver and equal to gold; stability at high frequencies better than gold or silver; strong film bonding characteristics; and compatibility with most solders. These benefits, however, do not come without cost. The inherently reactive nature of pure copper, while providing unique performance properties, makes it difficult to process. Unl i ke precious metals which can be fired in air, copper would oxidize and so requires special furnaces and atmospheres. Despite these difficulties, the transition from precious metal thick film systems to copper is gaining momentum. Manufacturers of high density, high performance circuitry are exploring the performance advantages of copper over gold and silver and the manufacturers of consumer products are considering the potential cost savings of copper over silver-palladium. Sherritt has developed a fine copper powder for this industry. Through association with the ink manufacturers, it has been found that performance properties of the ink vary with the physical and chemical characteristics of the powder. Production Process The production of very fine copper powders at Sherritt is based upon the disproportionation of cuprous ions as outlined in Equation [1] (1).

Jan 1, 1990

By Alfred Wild

The Kraftile Co. plant, Fremont, Alameda County, Calif.--the largest producer of glazed, structural wall units west of the Rocky Mountains--maintains modern processing facilities to evaluate and blend a wide variety of clays from several sources to produce quality products. The report desribes the prospecting, exploration, and test methods used to locate raw material sources and covers processing methods, cost factors, and trends. Also, the geologic and ceramic factors are considered in a general discussion of the economics, potentials, and requirements of clays as raw materials for ceramic tile manufacturing.

Jan 1, 1963

By S. Perla

Two of Peabody Western Coal Company&apos;s mine operations are the focus of this paper ... Black Mesa Mine and Kayenta Mine, both located in Northern Arizona. These two locations are unique for a variety of reasons. ? The two mines have only two customers, both power plants, one the Southern California Edison&apos;s Mohave Generating Station near Laughlin, NY, the other the Navajo Generating Station near Page, AZ. Close in proximity, these two locations ships nearly 12 million tons of coal per year. ? Material is shipped to these customers two ways: via a 273 mile underground slurry pipeline, which by the way is longest in the world, and by a 17 mile long conveyor to four storage silos. Product is then shipped via train from the storage silos to the plant sites.

Jan 1, 1995

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

Researchers from the U.S. National Institute for Occupational Health and Safety (NIOSH) studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the continuous personal dust monitor) within a sociotechnical system (STS) framework to mitigate respirable dust sources. The results address how to best incorporate the overarching principles of meta-design STS during the technology integration process. Specifically, quantitative and qualitative data show that a prominent focus on the social factors within an STS framework could help reduce organizational unpredictability and may improve communication within the system to help reduce technology adoption time.