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By P. A. Kennedy

An environmental assessment or impact statement for onshore waste disposal under the Notional Environmental Policy Act is expected to occur with the development of commercial deep seabed mining. An environmental assessment was conducted in order that testing and refinement of nodule waste disposal techniques can he completed prior to 1988, when commercial seabed mining can begin under U.S. legislation. Within this study three classes of process and four classes of waste disposal technique were identified, and five sites were selected as representative of first-generation nodule operations. Each realistic site/process/disposal technique combination was compared against potential effects to determine important characteristics of the rejects and the sites. Regulatory requirements were also considered at each site to identify important issues and their effect on the permitting process. Principal conclusions in the report are the following: (1) uncertainties exist in the regulatory regimes for hydrometallurgical process tailings, primarily regarding classification as hazardous waste; (2) slogs from nodule processing are expected to be inert and relatively easy to dispose of at all sites; and (3) additional physical and chemical information on properties of rejects from all processes is necessary to predict environmental effects.

Jan 1, 1982

By A. George Stern

[In the examination of bentonitic clay suspensions used for oil-well drilling fluids3/ (and for other purposes, such as a core binder for foundry sand) it is important to have comparative tests for evaluating them. A satisfactory clay for these and other purposes should have the property of forming what is commonly called a "gel," but the measurement of this property has been a real problem. To date the solution has not been satisfactory, and some of the difficulties are considered in, this, paper, which describes a simple form of instrument (identified as an eykometer) for measuring the yield point under hydrostatic conditions of non-Newtonian clay suspensions, including those muds that are thixotropic. An oil-well drilling mud serves several functions, many of which depend on the "gel" characteristics of the mud. Among the more important functions are: (a) To plaster the sides of the hole to prevent caving of the walls; (b) to prevent the loss of the circulating fluid out of the hole by seepage; (c) to carry sand and cuttings out of the hole to the surface as they are formed by the rotary drill; and (d) when circulation of the fluid stops for shut-down or other unavoidable cause, to hold the cuttings in suspension by the setting up of the gel, thereby avoiding the difficulties that result when these cuttings are allowed to fall through the fluid and pack at the bottom of the hole.]

Jan 1, 1940

By M. S. Cetiner

This report describes the prototype development If a medium to high voltage coupler, suitable for underground coal mining operations. The coupler has such unique features as automatic dust covers and continuous phase pin shielding. The coupler is rated at 7500V and 250A continuous operation.

Jan 1, 1982

By A. George Stern

In the examination of bentonitic clay suspensions used for oil-well drilling fluids3/ (and for other purposes, such as a core binder for foundry sand) it is important to have comparative tests for evaluating them. A satisfactory clay for these and other purposes should 'rave the property of forming what is commonly called a "gel," but the measurement of this property has been a real problem. To date the solution has not been satisfactory, and some of the difficulties are considered in, this, paper, which describes a simple form of instrument (identified as an eykometer) for measuring the yield point under hydrostatic conditions of non-Newtonian clay suspensions, including those muds that are thixotropic. An oil-well drilling mud serves several functions, many of which depend on the "gel" characteristics of the mud. Among the more important functions are: (a) To plaster the sides of the hole to prevent caving of the walls; (b) to prevent the loss of the circulating fluid out of the hole by seepage; (c) to carry sand and cuttings out of the hole to the surface as they are formed by the rotary drill; and (d) when circulation of the fluid stops for shut-down or other unavoidable cause, to hold the cuttings in suspension by the setting up of the gel, thereby avoiding the difficulties that result when these cuttings are allowed to fall through the fluid and pack at the bottom of the hole.

Jan 1, 1940

By Sangseom Jeong, Kyoungyul Kim, Jaeyeon Cho

"Abstract The lateral earth pressure of vertical circular shaft is investigated by using experimental tests and a theoretical analysis. The emphasis was quantifying on the magnitude and distribution of a lateral earth pressure measured by three-dimensional arching effect. A framework for determining the earth pressure distribution on the basis of both centrifuge model and full-scale field test results is introduced. Through these studies, it is found that the lateral earth pressure decreases within active displacement (dh/H: 0.2×10-2, dh: horizontal displacement, H: Height of vertical shaft) of wall at deep excavation and the arching effect is more significant for deep excavation than for shallow excavation. It is also found that the lateral earth pressure acting on a vertical circular shaft considering arching effect is 70% smaller than that calculated by Rankine theory, and thus represents a significant improvement in the prediction of realistic earth pressure for vertical circular shaft subjected to arching pressure.INTRODUCTIONIn South Korea, an increasing need for underground excavation and the application of the vertical circular wall (i.e. vertical shaft) is becoming an important issue in engineering practice. Here the vertical circular wall is generally embedded in soft or hard rocks through weathered soil varying thicknesses ranging up to 15 m. Since 1980, a number of huge excavation projects such as underground space for constructing power stations, subways, high-speed railways, and many lifeline constructions have been performed in urban areas (Jeong and Seo, 2004). Although there have been considerable advancements in construction techniques involving vertical circular wall, it is still very important for tunnel engineers to control the lateral earth pressure. Additionally, Proper estimation of earth pressures is a key factor in design of vertical circular wall. Because of three dimensional arching effects, i.e. convex arching and/or inverted arching, the earth pressure acting on a circular type of wall is less than other types. Thus, the vertical circular wall is generally used."

Jan 1, 2014

By Ahmadzadegan. Arash, Anil Saigal, Michael A. Zimmerman

"In this study, the rheology of liquid crystalline polymer (LCP) melts through simplified 2-D and 3-D die geometries is simulated using Polyflow™. It is known that rheological properties of LCPs are close to long chain polymers and their directionality is close to those of small molecule liquid crystals (SMLCs). As a result, different rheological models (both viscoelastic and generalized Newtonian) for long chain polymers in Polyflow™ were investigated based on the available capillary rheometer data. By varying the parameters in these models, it is possible to adjust the effect of shear viscosity, normal stress differences and relaxations times on the rheology of the polymer. The free surface of the extrudate coming out of the die is simulated and the amount of die swell for different types of rheological models is compared. This study indicates that the Bird-Carreau model best applies to thermotropic LCP materials as quantified by die swell. Since the rheology of the LCPs affects the orientation of the crystals, the result of this simulation can be further used to predict the orientation of crystallines inside and outside the die.IntroductionAny rod like molecule or crystal tends to orient itself in the direction of shear as it moves within a flow. Since polymers consist of long chains of molecules, they experience the same phenomena when flowing in the melt condition. For most polymers, the molecules change direction and distribute uniformly in space during the solidification. However due to the higher inertia of the crystals in the liquid crystalline polymers, the oriented crystals will keep their order during the solidification and as a result the final product will show anisotropy in material properties."

Jan 1, 2012

By G. Zhan, P. Mousset-Jones, G. Danko, J. J. K. Daemen, C. Mezei

Paper presented at the conference Risk assessment in the extractive industries, held in Exeter, 23-24 March 1994, and first published London: IMM, 1994, preprint volume. 18pp., 12 refs. (Originally entitled: Tunnel roof diagnosis using a robotic sensor test bed.) An integral roof diagnosis method is proposed to assist in assessment of risk regarding the stability of an excavation. A Robotic Sensor Test Bed (RSTB) is being developed for the characterisation of roof stability. The sensor test bed consists of a sonic/ultrasonic wave response sensor, a laser surface profiler and a surface temperature sensor. These sensors are mounted on an articulated robot manipulator for performing remote-controlled or fully automated diagnoses. A number of laboratory and field sonic/ultrasonic tests were conducted. A high-energy ultrasonic transducer and an impact device were used to resonate rock slabs. The fracture depths of the slabs were found to be inversely related to the measured resonance frequencies. The agreement between identified and actual dimensions was acceptable. Field tests also showed that loose rock on the surface can be clearly distinguished from solid formation by comparing their wave responses. The robotic laser profiler part of the RSTB was used to measure surface geometry. Different scanning methods are being developed to achieve the fastest and most precise measurements and to provide pertinent information about rock joints and major fractures

Dec 1, 1994

By Frederick M. Fowkes

Dusts can be filtered out of air streams onto polymer surfaces by electrostatic trapping resulting from the spontaneous transfer of electrons upon contact between dust particles and the polymer surfaces. Such spontaneous contact electrification has been studied quantitatively in this contract with the aid of modern semiconductor charge-sensors with the aim of determining what basic principles govern the sign and magnitude of contact electrification. Information obtained by capacitance-voltage measurements of thin polymer films on silicon showed that charges as large as 4 x 1012 electrons per cm2 develop spontaneously, and that such a charge gives adhesional forces of 165 pounds per square inch (11 atmospheres). Direct measurement of dust polymer contact electrification, using silicon surface channel conductance sensors, also showed spontaneous charges of more than 1012 electrons per cm2. Some polymers can either donate or accept electrons. These included chlorinated polyethylene, chlorinated polypropylene, polyethylmethacrylate, and a copolymer of maleic anhydride with n-octadecylvinylether. Other polymers never accepted electrons but could donate electrons; these included polystyrene, pulychlorostyrune, polyvinylchloride, polyvinylacetate, a polycarbonate (Lexan), and cellulose tributyrate. Contact electrification studies were made with dusts (coal dust, a channel black, or a silica powder) contacting thin films of various polymers solvent-cast onto the semiconductor charge-sensor. Sometimes charging was instantaneous and sometimes slower, but in all but one case (coal dust on a copolymer of maleic anhydride with n-octadecylvinyl ether) the charge trunsfer was a donation of electrons by the polymer to the dust. Some

Jan 1, 1973

By J Morton

The Resource Management Act 1991 represented an innovative and unique piece of planning and environmental legislation when it was introduced. Since the Act was passed into law in 1991 it has been subject to nine amendments, many of which were of the ætinkerÆ variety. These amendments recognise that the Act has not been as successful in providing the æone-stop shopÆ for resource users that the Act was hoped to be. The latest and most significant attempt at changing the Act was the Resource Management Amendment Act 2003. The amendments made by the Amendment Act have proved to be largely unsuccessful in achieving any significant changes to the way resources are managed in New Zealand, and have failed to address many of the concerns which drove the original Resource Management Amendment Bill in 1999. The recent decision to discontinue further investment in Project Aqua has once again placed the Act in the spotlight as a significant hand-brake on major projects. This particular event has led to yet another review to be undertaken this year. The review will focus on five key areas:   1.   achieving the right balance of national and local interests; 2.   improving the design and process for local policy formulation; 3.   improving the consent decision making process; 4.   allocation of natural resources (water, air and geothermal); and 5.   supporting measures for building capacity and promoting best practice and implementation at the local authority level.  It is important for the business community and the mining industry in particular to seize the opportunity that this review provides to make sure that any amendments undertaken as a result of the review achieve the aims listed above. The review needs to be considered in light of the current regime for the management of natural resources in New Zealand. In addition to the Resource Management Act 1991, the Crown Minerals Act 1991 and the Building Act 1991, which form the core resource statutes in New Zealand, there have been other developments affecting the regime. Special legislation over and above the Resource Management Act 1991 has been enacted to protect the Hauraki Gulf and special legislation is currently being considered to protect the Waitakere Ranges in Auckland. In the Hauraki District mining is prohibited in some areas and a plan change mechanism is specified as the appropriate tool to use in the event a mineral resource is to be developed in those areas. The current review is a further opportunity to remedy the inadequacies of the Act.

Jan 1, 2004

By Michael G. Zabetakis

The spillage of liquid diethyl ether in rooms at floor level and 3 feet above the floor resulted in flammable vapor-air mixtures in the immediate vicinity of the exposed liquido The liquid temperature was found to decrease by as much as 35° C., with a resultant decrease in vaporization rate. A search of the literature yielded numerous references to unstable peroxide (residue) formed by the autoxidation of ether. Such residues appear to constitute an explosion hazard in the condensed state.

Jan 1, 1962

By C J. de Beer

The Kwaggashoek East pit is one of the four production areas of Thabazimbi Iron Ore Mine. The Kwaggashoek East Open pit mines through the abandoned sublevel caving operations of the Kwaggashoek East underground workings. A risk assessment indicated that the primary risk is the occurrence of surface subsidence. Based on local knowledge, a hypothesis, that most of the cavities were filled with broken rock as a result of roof collapse and bulking of failed material was formulated. To test the hypothesis a number of geophysical methods as well as probe drilling was utilized. The results of the resistivity, gravity and ground penetrating radar surveys were inconclusive in determining the position of voids. Either there were no voids present or the resolution of the surveys was not high enough to pick it up. It is accepted that only small voids remained, and that the supported roof hypothesis is valid. As a precautionary measure all the production blast holes within the caving area were over-drilled by forty percent. This would collapse the roof of any small voids or tunnels immediately below the block. This operation proved to be successful as two of the three underground levels have been mined out with no subsidence occurring in the pit floor.

Jan 1, 2006

By Rolland R. Mates

This paper describes the use of post- tensioned rock anchors to reduce the risk of future damage to a residential structure as a result of coal mine subsidence. The project described in this paper was performed by the Office of Surface Mining Reclamation and Enforcement (OSMRE) of the U. S. Department of the Interior. The OSMRE was created to administer Public Law 95-87, the Surface Mining Control and Reclamation Act of 1977. The responsibilities of OSMRE include "reclamation and restoration of land and water resources, adversely affected by past coal mining including prevention, abatement, control of coal mine subsidence. ?('l) Consequently, OSMRE has been addressing mine subsidence problems since its initial subsidence stabilization project in 1979. Stabilization activities have primarily consisted of supporting the overburden material by injecting materials through drilled bore holes into the underground mine voids. Injection of various materials into mine voids, including fly ash mixtures, coal refuse, cement grout, and gravel has proven to be a successful method of reducing mine subsidence-related surface movements, and has been extensively utilized in mitigating mine subsidence problems. However, the cost of drilling for injection can be extremely high in areas where the depth to the coal seam is great.

Jan 1, 1986

By Stephen H. E. Phillips

This report outlines the modifications that have been carried out to the original prototype rectangular shaft sinking equipment for its use in a circular shaft. The surface testing of the machine is described where seven, 24 ft. diameter shafts were excavated to an average depth of 21 ft. at rates ranging between 1 ft/hr and 1.9 ft/hr depending upon the prevailing conditions. The durability and productivity standards for the equipment were established indicating that the objectives of the project had been realized. That is, when using the machine the sinking rates could be increased by 25% and costs reduced by a corresponding amount compared with conventional drill and blast methods. In addition it was shown that the machine had been developed to a state of fitness for sustained underground use.

Jan 1, 1981

By Piyush K. Dutta

This report describes the design, development, manufacture and incorporation of noise control features on a jumbo drill and the results of successful tests of this drill in surface and underground mines. The noise-reducing features developed under this program are applicable to future designs of jumbo mounted drills that can be cost effectively manufactured and have the potential to reduce noise levels at the operator's position from 115-120 dBA to 95 dBA or less without a reduction of currently attainable drilling rates.

Jan 1, 1985

By W Barry Gregg

The rock blasting and mining industries use a system of detonators and explosives for mining operations. Many detonators use small metal bridgewires, which are heated by passing a current through the wire, heating and igniting the pyrotechnic powder in contact with the wire, Typical bridgewires require a current of at least 3 amps, applied for a few milliseconds, for an explosive output. The semiconductor bridge (SCB), in comparison, initiates an explosive in 0.01 to 0.1 of a millisecond.

Jan 1, 1992

By Sterling J. Anderson

Through the use of nondestructive testing techniques, the Bureau of Mines is pursuing a goal of improving the efficiency of the rock excava-tion process. Toward this end, 44 laboratory tests were conducted to identify a practical method of monitoring fracture development in rock, as caused by an excavation tool. An acoustic emission CAE) transducer was used to monitor the test samples as they were loaded. The signal from this instrument was recorded in real time along with the radial and axial loads generated by the fracturing device. Through the review of these signals on a common-time base, it was possible to see the relationship between the developing fracture and the loading conditions. As a part of the posttesting investigations, samples that were pletely fractured were sawn and ground to expose the fractures. examination of these samples allowed approximations to be made incom-Visual of the total surface created. Surface area approximations were also made for the completely fractured samples. Quantitative analyses· of the AE signals were conducted for comparisons with the calculated surface areas.

Jan 1, 1987

By J. K. Whyatt

The paper presents an approach to design a multi level room and pillar layout in a 40m thick seam overlain by a major aquifer. The design was required to maximise extraction with due consideration of the general stability of the workings, the potential water hazards, and spontaneous combustion risks due to air leakage between horizons. The approach utilised was a combination of empirical pillar sizing for water hazard control with numerical modelling to assess potential interactions between horizons. The numerical modelling allowed the size of interleaves, and the appropriate staggers to be optimised in terms of stress distribution. The stress distribution allows both the general stability of the openings and more importantly the permeability changes around the openings to be determined. The permeability of coal is sensitive to stress, and an empirical stress to permeability relationship, and theoretical permeability to flow leakage relationship has been applied to interpreting the relative spontaneous combustion risk associated with each of the proposed layouts. The final proposed design is a compromise between maximum exploitation of reserves and consideration of water hazards and of spontaneous combustion risk. Further more detailed design will be required as more comprehensive data on the geotechnical properties of the coal and overburden become available.

Jan 1, 1996

By M. L. Free, L. Anthian

Electrochemical, chemical, and image analysis techniques were utilized together with statistical analysis methods to determine the effect of various anode impurities on copper electrorefining performance. Results indicate that arsenic is a beneficial anode impurity. Anode lead and sulfur are shown to decrease electrorefining performance. Specific emphasis is given to the influence of individual elements on current efficiency, slime particle generation, and cell voltage parameters.

Jan 1, 2000

By Art Cooper

Granulation systems are common in the metals industry. The process of granulating slags, mattes and metals is more than a century old, and a number of different systems have been developed to accomplish this task. These systems have followed an evolutionary path, and may be characterized by common elements in terms of molten material handling, granulation methods and post-granulation processing. This paper will summarize the more common systems used in the metals industry, with particular reference to non-ferrous applications.

Jan 1, 2006

By William A. Beck

The Construction Aggregates Corp. operates a plant for processing sand and gravel from two deposits in Ottawa County, Mich. The bulk of the sand is obtained from a sand dune on the shore of Lake Michigan, and the gravel is dug from a glacial-drift deposit farther inland. Mining is done with draglines, and the material, both at the digging site and in the plant, is moved mainly by systems of conveyors. The Ferrysburg plant serves customers along the Great Lakes, which is unusual for a business normally local in character. Annual production exceeds 1-1/2 million tons of sand and gravel as concrete aggregate and 200,000 tons of core sand for foundry use.

Jan 1, 1962