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By S. Schina

Part of the Imittos Western Peripheral Motorway in Athens is the twin road tunnel in the vicinity of American College, with 20m excavation diameter. In the paper, the environmental and other requirements, the geometry and the geological – geotechnical characteristics of the rock formations in the construction area are given. Information regarding the modeling and analysis methods that are used for the design of the temporary support, the final lining and the wedge and slope stability analysis is described thoroughly. Finally, the results of the analyses are compared with these of measurements and general remarks during the construction of the tunnels.

Jan 1, 2001

By M. P. Murphy

The state of Illinois is committed to direct support of the Illinois coal industry. The Illinois Department of Commerce and Community Affairs’(DCCA) Office of Coal Development (OCD) provides incentive programs for coal and energy development. Illinois coal programs include tax and financing incentives for new coal-fired generation, infrastructure grants to expand coal mining and transportation systems, research and development grants to initiate and advance clean-coal technologies and demonstration grants to bring advanced coal utilization technologies to commercial-scale readiness. As a result of these efforts, the Illinois coal industry is reinventing itself and is now more productive and competitive than ever before.

Jan 1, 2003

By J. Eldridge, A. J. Carter, D. N. Leavell

Minpro International has developed an innovative, flexible¬shaft impact crusher that produces glass aggregate from mixed¬color, post-consumer glass. The crusher operates with low power and generates a subangular aggregate, with minimal fines. Output is screened to yield sized aggregate, which can be used directly as surfacing material in Owens Corning's shingle process. Metal, plastic and paper waste is preferentially removed by the Minpro system. Duval County and the City of Jacksonville collect more than 12,000 tons of glass bottle waste per year. It is anticipated that a successful end-use application by Owens Corning, will allow increased collection and cost-effective glass recycling in north Florida.

Jan 1, 2002

By R. Hogg

The various sub-processes which, together, make up the unit operation of froth flotation all depend on the characteristics of the feed solids, the solution phase, the air bubbles and the mechanical/hydrodynamic action of the machine. Characterization is obviously necessary for evaluation and process control, but the relationships between characteristics and process response are often unclear. A model-based characterization scheme is proposed in which material and system characteristics are evaluated in the context of simplified models for the individual subprocesses. The general basis for such an approach is discussed using the process of particle attachment and the influence of mineral liberation as examples.

Jan 1, 1989

By M. Josick Comarmond, Paul L. Brown, Greg P. Timms, A. Ian M. Ritchie, John W. Bennett

Geochemical kinetic models have only become available in recent years and their utilisation in the prediction of effluent chemistry from sulfidic waste rock piles is even more recent. The models used to date, however, have incorporated some questionable assumptions. This paper shows how geochemical, mineralogical and physical field data have been coupled to remove some ill-founded assumptions in the construction of a geochemical kinetic model. Further, the paper discusses a comparison between the observed effluent chemistry from a waste rock dump at the Rum Jungle copper/uranium mine in northern Australia with model predictions. In general, there is good agreement between the two, although an anomalous result is discussed.

Jan 1, 2000

By Robert L. Sundeen, Richard V. Wenberg

INTRODUCTION Early rock-bolting practice usually consisted of ran¬domly installing bolts, using hand-held drilling equip¬ment such as air-leg mounted sinkers or stopers. As bolting technology evolved, the practice of installing uniform bolt patterns was developed, utilizing random bolt installation as required within the uniform pattern. The uniform rock-bolting technique, when used as the principal method of rock support, requires drills and jumbos designed specifically for rock bolting. This equipment is similar to conventional face drilling machines, except that the jumbos can orient the drills to obtain any necessary bolting angle; often, this means bolts may be installed at or near perpendicular to the centerline of the drift or stope opening. Fig. I shows a typical rubber-tired rock-bolting jumbo of the type commonly used in drifts and room-and-pillar mining. Modern rock-bolting jumbos are capable of drilling the required holes, inserting rockbolts, and torquing them to proper levels. Jumbos also are available for use with resin-anchored bolts. Probably the most unusual of this type utilizes a rotating bolt turret that carries the rock drill, resin charging unit, and the bolt in a single mechanism. Once the turret is loaded with the resin and bolt, further manual effort is not re¬quired. Drilling and bolt placement are accomplished by the operator from a station remote from the bolt site. Fig. 2 shows this turret device. Roof-bolting jumbos are available mounted on rail, crawler, or rubber-tired chassis. Various types of rock drills are used. Depending upon the type of rock, these may include rotary, percussion, or rotary-percussion drills. Fig. 3 shows a typical rail-mounted jumbo. CONDITIONS INFLUENCING APPLICATION General Rock Conditions Rock-bolting generally is applicable in moderately hard to hard rock. No particular type of rock is ex-

Jan 1, 1982

By Brendan Reilly, Jon Isaacson, Paul McDermott

Kenny/Shea JV is constructing the water intake tunnel for the new Elm Road Generating Station, a supercritical coal-fired power plant in Oak Creek, Wisconsin, being built by Bechtel Power Corporation. The intake tunnel system consists of a temporary mining shaft, pump house and intake channel riser shafts, and four lakebed intake shafts. An 8.33 m diameter, 2,800 m long TBM mined rock tunnel is being constructed to connect the shafts. The intakes are located 2.4 kilometers offshore in Lake Michigan. The shafts and tunnel are being constructed in glacial tills and Silurian Dolomite. The estimated tunnel completion is December 2007.

Jan 1, 2007

By Edward S. Plotkin

The tunneling construction industry faces a new challenge in endeavoring to comply with the multitude of regulations and standards of the Occupational Safety and Health Administration and to work following accepted and experienced tunneling practices. Tunnel inspections appear to be gaining in priority. The national OSHA inspection activities reported for the year 1976 in the construction industry are as follows: 989 Inspections 45 As result of Accidents 186 As result of Complaints 605 General 153 Follow Up 34% Were found to be in compliance 714 Citations were Issued 1,825 Violations were found (201 of which were serious; 1573 were non-serious; 51 were imminent danger. There were no recorded failures to abate a violation in our industry.) The five general priorities by which a company would be scheduled for an inspection in descending order are: imminent danger situations, reports of fatal accidents or catastrophies, inspections in response to valid employee C( taints, inspections of work places covered by National Emphasis Program NEP, (OSHA's NEP has been designed to impact on any industry having a very high injury or illness rate) and finally random inspections of work places covered by OSHA. The following criteria in selecting companies for random inspections is used by OSHA.

Jan 1, 1979

By Terry S. Maley

With some exceptions, minerals may be acquired on the unappropriated public lands by one of three methods: (1) mining claim location under the General Mining Law of 1872; (2) mineral lease under the Mineral Leasing Act of 1920; and (3) sale contract under the Mineral Materials Act of 1947. Leasable minerals such as oil, gas, coal and phosphate are specifically designated as leasable in the Mineral Leasing Act so the method of acquisition is clear. As a general rule, metallic minerals are acquired by mining claim location. However the nonmetallic minerals, most of which are industrial minerals or gemstones, present a more difficult problem. These minerals are acquired either by mining claim or a sale contract depending on their chemical composition, physical properties and the use to which they are put. The Act of July 23, 1955 (30 U.S.C. 61 1) provided that uncommon varieties of sand, stone, gravel, pumice, pumicite or cinders are locatable; whereas, common varieties of such minerals may only be acquired by a contract of sale. The widespread location of mining claims to appropriate such deposits has caused many land management problems. Federal court and Interior decisions offer the most useful guidelines in determining the most appropriate method of acquisition.

Jan 1, 1991

By M. A. D. Azevedo, J. D. Miller, R. Kobler, E. Mutkowska

Up to 3 million tons of automotive shredder residue (ASR) is generated annually in United States. Plastics are the most valuable component of the ASR material making up approximately 25% of the total weight. In order to reuse these plastics, a selective process is required to separate each plastic, with very high purity and favorable economics. One separation technique, which may be able to selectively recover the plastics from ASR, is flotation. The preliminary flotation results have demonstrated that acrylonitrile-butadiene-styrene (ABS) and polycarbonate (PC) can be selectively separated from the model ASR feed, the PC/ABS/PA 66 system, by appropriate control of the surface chemistry.

Jan 1, 2001

By E. Steel

The asbestifom habit is most commonly developed in certain amphiboles and chrysotile, but other minerals may also crystallize with this unususual habit, The habit may be characterized by 1) a fibril structure, single or twinned crystals of very small widths (generally less than 0.5 inn) which have gram with a common fiber axis direction but which are disoriented in the other crystallographic directions, 2) anomalous optical properties, primarily parallel extinction, 3) unusual tensile strength, 4) high aspect ratio, and 5) flexibility. In addition, there is evidence to indicate that some amphibole asbestos may have unusual surface properties.

Jan 1, 1979

By Emil O. Frind, David W. Blowes, K. Ulrich Mayer

The multicomponent reactive transport model MIN3P can be used to simulate the evolution of pore water, pore gas, and the mineralogical composition in mine waste environments. The model is formulated for variably-saturated conditions, considers transport of dissolved and gaseous species, and describes geochemical reactions based on a partial equilibrium formulation. Reaction processes included are complexation, oxidation-reduction, ion-exchange, mineral dissolution-precipitation and gas exsolution- dissolution reactions. An example application, describing the generation of acid mine drainage and subsequent reactive transport for a ID-vertical profile in a tailings impoundment near Elliot Lake, Ontario, is provided.

Jan 1, 2000

By S. Behl, Pradip

Selective-flocculation process development generally involves single-mineral flocculation tests to identify the appropriate polymer experimental conditions for achieving the desired selectivity. Invariably the selectivity predicted on the basis of such tests is not realized when mixed-mineral tests are conducted. A systematic experimental investigation revealed that adsorption of the polymer on various substrates is critical to selecting the suitable flocculant. Simultaneously, a mathematical model was developed to predict the overall process of efficiency with a given polymer. In this paper, the results of these efforts to scientifically design a suitable selective flocculation process are presented.

Jan 1, 1994

By P. W. Johnson, H. Fan, S. B. Patton, T. Novak, R. L. Sanford

A computer model is presented that quantitatively uses the relationship between the interactive and dynamic processes of methane drainage, mining, and ventilation. The model includes simulation of the coalbed methane reservoir for prediction of gas-emission rates under the influence of degasification wells and longwall mining, ventilation network-generation and ventilation simulation. As mining progresses step-wise through the coalbed-methane reservoir, the ventilation network is created and subsequently simulated, iteratively determining fan requirements to safely reduce methane concentrations. The model can be used to quantitatively study the effectiveness of methane degasitication on the ventilation system in a longwall panel.

Jan 1, 1995

By D. Papacharalampos

A combination of decision- theoretic and knowledge-based methods can be used to classify rock-types from satellite data both efficiently and accurately. An expert system utilizes knowledge-based rules, as a field geologist does, to produce results that make geological sense. Our expert system (GEMS), first processes background information from preexisting knowledge and develops a plan, then classifies individual pixels, and finally generalizes the results using geological rules and plots a map. The system is implemented on a microcomputer and is inexpensive enough to be a part of the standard equipment of any geologist who prepares reconnaissance maps.

Jan 1, 1986

By Guoming Liu, Weibai Hu

The designing aspects of column profile, cross-section and height, types of aerator or air sparger, and feeding and discharging devices have been designed and tested. In operating aspects, the flotation column: has beer, compared with the conventional mechanical flotation machine in large- scale plant practice. It has been found that the reagent conditioning time and the slurry residence time required in the column are longer than those in the mechanical flotation machine. The general opinion is that the flotation column can show some effectiveness in specific cases as long as it is properly designed and carefully controlled.

Jan 1, 1988

By Harold E. Goetzman, Blair R. Benner

The U.S. iron ore industry is located primarily in Northern Minnesota and Michigan's Upper Peninsula with one additional small plant in Missouri. There are currently some 10 plants operating that produce about 48 million tons per year of pellets. The major reagent use occurs in the three general areas of: flocculation, flotation and pellet additives. Minor areas of usage are for corrosion inhibition and dust suppression. Current practice as to types of reagents, consumption, and method of application are reviewed. The interaction of reagents with other parts of the process are discussed. Also included is a discussion of future reagent needs.

Jan 1, 1994

By J. F. Peterman, M. C. Roberts

The success of any industrial mineral project requires an accurate forecast of the demand fir the material as well as accurate projections of costs and prices. This paper develops a general method of predicting mineral requirements and applies it to the case of graphite. The basic method is to explain graphite consumption in each of its major uses by the output and manufacturing technology of the using industry. Once these underlying factors are determined, they can he projected to establish future requirements. This forecast is critical to the evaluation of a new source of supply, such as the graphite resources of Upper Michigan.

Jan 1, 1990

By D. M. Smith, M. J. Meulendyke, P. J. Moroz

An extensive program of marked ball wear testing (MBWT), laboratory corrosion studies, and worn ball surface analyses has been used to gain insight about the role of corrosion in the overall wear process. In some environments, localized corrosion is observed; the actual wear mechanisms in such cases are pitting/spalling and abrasion. Factors affecting the occurrence of pitting include the abrasiveness of the ore, corrosivity of the slurry, corrosion resistance of the media, and galvanic coupling effects. Elimination of pitting substantially improves overall wear resistance. When pitting is not observed, the contributions of general corrosion are significantly less.

Jan 1, 1988

By Patrick Doig, Ross Webb

The Bradshaw Section 5A Interceptor involves the construction of two miles of 108-inch, finished diameter tunnel in dry soils. Excavation is generally by Lovat TBM with ribs and lagging support. The tunnel is beneath a recreational parkway and stringent measures have been enacted to preserve the parkway and minimize disruption to the neighborhood. Apart from these constraints, the project would have been unremarkable but for the intervention of CalOSHA and the local fire department who ordered extraordinary fire protection measures. The paper discusses the cause and effect of these measures and comments on the potential repercussions for other projects.

Jan 1, 1999