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By Thomas M. Gurtowski

The New Pacific Northwest Baseball Park, now known as Safeco Field, is located directly south of the Kingdome in Seattle, Washington, and will be the new home of the Seattle Mariners baseball team. The location of the ball field is shown on Figure 1, Vicinity Map. The seating capacity is 45,600, and outfield distances are 331 feet in left, 405 feet in center, and 326 feet in right field. The overall dimensions of the stadium are 680 by 800 feet. It is bordered on the east by the Burlington Northern Santa Fe Railroad main line. A unique aspect of this ballpark is the retractable roof with a north-south span length of 660 feet. The roof consists of three separate sections that roll on elevated rails running east-west on the north and south sides of the stadium. The soil conditions consisted of near-surface fill underlain with alluvial and Estuarine deposits to depths of 60 to 80 feet. The bearing soils consisted of very dense, glacially overridden deposits. Groundwater is 4 to 7 feet below the ground surface, and the alluvial deposits are subject to liquefaction during a strong motion earthquake.

Jan 1, 1998

By Li Keqiang

This paper discusses the pile foundation of tall buildings in Shenzhen region. For 156 constructed tall buildings exceeding 18 storeys, about 86. 5 per cent of the sum. The two main types of foundation used are the semi?machine?bored/slurry drilled cast?in?situ pile and the excavation pile (hand ?dug caisson). The engineering geologiical condition in Shenzhen was analysed. In general, the bed rock level is not too deep. It belongs to hard rock, but the geologic structure is more complex and the tectonic fissures is plenty. According to experiences of the researches, tests, designs and constructions of pile foundation, we present the basic design principle of pile foundations for tall buildings as follows; (1) pile strength control to select the pile type and to choice the cross sectional dimen­sions, must be in compliance with the strength of the pile. (2) bearing stratum strongly weathered, moderartely weathered and slightly weathered rock may be used as the bearing stratum. (3) bearing pile bored /drilled cast-in-situ pile designed as an end bearing pile. (4) friction pile precast concrete pile, prestressed concrete tubular pile and driven cast-in-situ pile designe as a friction pile. In case, pile design is in compliance with these principles, it may be safe, economical and reasonable.

Jan 1, 1991

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

C THRM 1 C CALCULATION OF MINE HEAD LOSSES FROM ALTIMETER SURVEY DATA TURN 2 C PENNSYLVANIA STATE UNIVERSITY - MINERAL ENGINEERING DEPARTMENT THRM 3 C THRM 4 C THRM 5 C THIS PROGRAM CALCULATES PRESSURE LOSSES USING THERMODYNAMIC RELATION- THRM 6 C SHIPS BASED ON POLYTROPIC FLOW BETWEEN STATIONS. FOR REFERENCE SEE THRM 7 C "A NEW TREATMENT OF MINE BAROMETER SURVEYS" BY M. J. MCPHERSON IN THRM 8 C 'THE MINING ENGINEER' NO. 109, VOL. 129, P 23. THRM 9 C THRM 10 C THRM 11 C THRM 12 C IDENTIFICATION OF ARRAYS THRM 13 C NOTE THE PROGRAM HAS BEEN DIMENTIONED FOR FOURTY (40) DATA POINTS THRM 14 C BASEC(6;2) BASE INSTRUMENT TEMPERATURE CORRECTIONS THRM 15 C TRAVC(6,2) TRAVERSE INSTRUMENT TEMPERATURE CORRECTIONS THRM 16 C BASER(I) BASE INSTRUMENT READING THRM 17 C TRAVR(I) TRAVERSE INSTRUMENT READING THRM 18 C TDRY(I) DRY BULB TEMPERATURE AT TRAVERSE STATION THRM 19 C TWET(I) WET BULB TEMPERATURE AT TRAVERSE STATION THRM 20 C ELEV(I) ELEVATION AT TRAVERSE STATION THRM 21 C VEL(I) AIR VELOCITY AT TRAVERSE STATION THRM 22 C TBDRY(I) DRY BULD TEMPERATURE AT BASE STATION THRM 23 C BASC(I) BASE READING CORRECTED FOR INSTRUMENT TEMPERATURE THRM 24 C TRAV(I) TRAVERSE READING CORRECTED FOR INSTRUMENT TEMPERATURE THRM 25 C BBASE(I) TEMPERATURE CORRECTED BASE READING IN BAROMETRIC THRM 26 C PRESSURE THRM 27 C BTRAV(I) TEMPERATURE CORRECTED TRAVERSE READING IN BAROMETRIC THRM 28 C PRESSURE THRM 29 C BTRAVS(I) BAROMETRIC TRAVERSE READING CORRECTED FOR ATMOSPHERIC THRM 30 C CHANGES THRM 31 C RELHUM(I) RELATIVE HUMIDITY THRM 32 C ASW(I) AIR SPECIFIC WEIGHT TURN 33 C R(I) GAS CONSTANT FOR MOIST AIR THRM 34 C STPRES(I) STATIC PRESSURE CHANCE BETWEEN STATIONS (I) AND (1-1) THRM 35 C TOPRES(I) TOTAL PRESSURE CHANCE BETWEEN STATIONS (I) AND (I-1) TURN 36

Jan 1, 1977

By Paul Wellman

The energy problem of the U. S; was emphasized by the oil embargo of late 1973 and early 1974 and it seemed for a time that the Federal Government, under pressure from the general public, might take some corrective action. However, this was not the case. With the gasoline lines gone and an apparent plentiful supply of petroleum products, public concern quickly dissipated., This country is more vulnerable to an oil embargo today than we were in 1973-1974 and this fact should be of concern to all our people. Since 1968, we have used oil and natural gas at a much more rapid rate than we have been able to find new domestic sources; thus, there is an increasing gap between domestic production and consumption and we have filled the gap with ever increasing oil' imports. These imports have increased at an alarming rate in the recent past, some 58 percent in 1976 compared with 1975. Imports are nearing 8 million barrels per day. Then, by applying some simple arithmetic, at $12 per barrel, the resulting trade deficit is $96 million per day or $35 billion per year. Obviously, this cannot be tolerated by our economy over a long period of time. Historically, we have shifted from one fuel to another as is shown in this slide. In 1850 about 90 percent of our fuel requirements came from direct combustion of wood, by 1900 we shifted to coal for 70 percent of our fuel, and now about 78 percent of fuel requirements comes from oil and natural gas. The difference is that the previous shifts were voluntary and the one facing us now is of necessity.

Jan 1, 1977

By E Portes, G Noble, J Roberto, A Stabile

Iron ore beneficiation plants are facing economic pressures to treat more challenging ore types, improve efficiency and improve product quality. Better control and stability of the plant process in the face of increasing feed ore variability has been a goal for many of the operations facing these challenges.Prompt gamma neutron activation analysis (PGNAA) technology has proven to be a successful measurement technique within an iron ore beneficiation plant. PGNAA was first developed in the early 1980s for the measurement of the elemental composition of bulk materials. Today, PGNAA technology is applied for elemental analysis within the iron ore industry on both bulk materials and slurries.Traditional composite sampling throughout the wet iron ore beneficiation process provides a delayed measurement of average properties but does not capture the true variability of the process in real-time. As such this is a limiting factor towards stabilisation and optimisation of the process. A PGNAA analyser provides real-time slurry elemental analysis of feed, concentrate and tails streams within the processing plant. The analytical data from the analyser can be exploited with a control strategy to correct and stabilise the plant on a much shorter time scale, delivering significant economic benefits and greater operational flexibility. The economic benefits include more stable product quality and a reduction in composite sampling and laboratory costs.Some example results will be presented from the Vale Vargem Grande iron ore beneficiation plants, which are utilising a six stream multiplexed Thermo Scientific PGNAA Slurry Analyser.CITATION:Noble, G, Stabile, A, Portes, E and Roberto, J, 2017. Real-time slurry elemental analyser for iron ore beneficiation plant control, in Proceedings Iron Ore 2017, pp 481–486 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By R. W. Bartlett

The extensive central Idaho black sand placer deposits are a potential source of rare earth elements, particularly the heavy rare earth elements that are not prevalent in commercial bastnasite deposits. These placers derive from the Idaho batholith. The geology, occurrence, and extent of these deposits are reviewed and the diverse mineral assemblages and complex mineral chemical compositions of these sands are described. Niobium, yttrium and thorium are also present in significant concentrations. The results of prior mining practice, including concentration and separation of the heavy minerals are reviewed. Technical approaches to extraction of rare earths from Idaho black sand concentrates are discussed.

Jan 1, 1992

By Christopher Mark, Gregory M. Molinda, Timothy M. Barton

The Coal Mine Roof Rating (CMRR) was first presented at this Conference nine years ago. Since its introduction, the CMRR has been incorporated into many aspects of mine planning, including longwall pillar design, roof support selection, feasibility studies, and extended cut evaluation. It has also become truly international, with involvement in mine designs and funded research projects in South Africa, Canada, and Australia. The purpose of this paper is to bring the mining community up to date with recent improvements and applications of the CMRR. The most important new development is a streamlined process for determining the CMRR from exploratory drill core. Just three types of information are now required: •Fracture spacing (or RQD) •Uniaxial compressive strength (or axial Point Load Testing) •Diametral Point Load Testing The moisture sensitivity adjustment has also been changed, and new research has related the immersion test to slake durability. Most recently, the CMRR has been implemented in a computer program, which can be obtained from NIOSH free of charge. The program facilitates calculation of the CMRR from either underground or drill core data. Values from many locations can be saved in a single file, and an interface with Autocad allows CMRR contour plots to be integrated into mine planning.

By L. D. Johnson

12 groups of 12 precast prestressed (PCPS) piles were driven in the lagoon of Kwajalein Island to support a dry dock. Pre-construction investigation of the calcareous coral sands and static pile loeid tests were performed to determine if the 7.9 by 7.9 cm (20 by 20 inches) by 26 m (85 ft) long PCPS piles embedded to a depth of 16 m (53 ft) would adequately support the dry dock. Driving records for production piles indicated that the blowcounts of the piles at the fincil embedment depth became substantially less than expected as piles wssre driven further toward the lagoon end of the dry dock and decreased to as low as 2 blows/ft. A supplemental investigation that included a static load test on a production pile, the driving of an indicator pile, and restrikes indicated that the pile foundation has adequate bearing capacity. The observed bearing capacity appears to be effected by several mechanisms including breakdown of cementation between sand particles, densification of the sands during driving, and dissipation of excess pore pressures and recementation after driving.

Jan 1, 1993

By Michael J. Sapko, William D. Monaghan, Michael A. Trevits

Mine seals are used extensively in underground coal mines to segregate mined-out areas and to isolate fire zones or underground areas that are susceptible to spontaneous combustion. Over the years, 30,000 mine seals have been erected in underground coal mines in the United States. Mine seals, along with rock dusting and ventilation, represent the fundamental means of preventing underground coal mine explosions. In this study the National Institute for Occupational Safety and Health (NIOSH) used ground penetrating radar (GPR) technology to determine if each of three test mine seals were uniformly constructed. Three mine seals representing different construction methods and materials (cast-in-place foamed cement; solid block, polyurethane foam and gravel; and wire mesh, rebar and gunite) were erected at the NIOSH Lake Lynn Laboratory’s underground mine as part of an on-going research program. The seals were imaged using GPR with 400-, 500-, 900-, and 1,000-MHz antennas. We found that variations in uniformity existed in the material for the cast-in-place foamed cement seal. Variations in uniformity also existed in the seal made from solid block, polyurethane foam and gravel. The post-processed radar records correlated closely with recovered core samples (areas of gravel and polyurethane foam, and areas containing only polyurethane foam). Finally, the radar records of the seal made of wire mesh, rebar and gunite showed the various components. The results of this work suggest that GPR could be used as a tool to evaluate mine seal characteristics and construction uniformity.

By I. Jauhari, F. Stober, D. Fowler, B. O. Wasmund, T. Miraza, C. Nichols, A. Taofik Hidyat, K. Said

The existing PT Aneka Tambang (Antam) ferronickel smelter located at Pomalaa, Indonesia consists of two RKEF lines with reduction furnaces nominally rated at 17 MW and 18 MW, respectively. The low power densities and heat fluxes allowed both furnaces to operate with falling water film shell cooling systems. The furnace campaigns comprised a 5-yearly cold shut -down for metal taphole area rebuild and a 10-yearlysidewall and hearth perimeter repair. Towards the end of these campaigns the furnaces would typically be operated at below nominal power due to excessive sidewall temperatures. In January 2001 Hatch performed a smelter study which proposed options which indicated the possibility of a single furnace operation for the smelter, elimination of lime addition and transition to shielded-arc operation with associated efficiency and throughput gains. This paper discusses the process of uprating the second?line furnace capability from 18 MW to 32MW following the decision by Antam to implement the recommendations proposed by Hatch. It will cover the development of scaled-up furnace design basis by Hatch and Antam with the enabling application of Hatch cooling and binding technology. To optimise the capital cost and maximise Indonesian supply content and post installation support, the scope was carefully and clearly divided between Hatch and Antam. The challenges, set backs and valuable learning experiences gained during the implementation of the retrofit include; ?The support and re-use of existing roof system and challenges presented in re-use of existing crucible support steel. ?Training and technical assistance for Antam operators to perform refractory and copper cooler installation and maintenance of crucible integrity technologies. ?Hearth integrity during start-up and development of an initial charge and start-up procedure to achieve planned thermal expansion of the hearth prior to bath formation ?Implementation of a sidewall hold-down system within the refractory sidewall due to space constraints ?Existing furnace foundation reinforcement to overcome lateral forces on furnace piers during crucible support steel expansion ?Conversion of an open-loop gravity feed cooling water system to a closed loop pressurised system with integrated emergency gravity feed and backup system ?Existing water treatment system and pumping system improvement and modification to meet copper cooling system requirements ?Integration of the new instrumentation control system designed by Hatch to increase performance of the furnace monitoring system and operation ?Uprate transformer capacity from 25 MVA to 40 MVA to meet with requirement of Shielded- Arc Furnace Operation.

Jan 1, 2007

By William E. Ford, Edward Salisbury Dana

URANINITE. Cleveite. Broggerite. Nivenite. Pitchblende. Isometric. In octahedrons (o), also with dodecahedra1 faces (d) ; less often in cubes with o and d. Crystals rare. Usually massive and botryoidal; also in grains; structure sometimes columnar, or curved lamellar. Fracture conchoidal to uneven. Brittle. H. = 5'5. G. = 9'0 to 9'7 of crystals; of massive altered forms from 6'4 upwards. Luster submetallic, to greasy or pitch-like, and dull. Color grayish, greenish, brownish, velvet- black. Streak brownish black, grayish, olive-green, a little shining. Opaque. Comp. -A uranate of uranyl, lead, usually thorium (or zirconium), often the metals of the lanthanum and yttrium groups; also containing the gases nitrogen, helium and argon, in varying amounts up to 2'6 p. c. Calcium and water (essential?) are present in small quantities; iron also, but only as an impurity. The relation between the bases varies widely and no definite for- mula can be given. Radium was first discovered in this mineral and it has been shown that it and the helium present are products of the breaking down of the uranium.

Jan 1, 1922

By Faruk Oksuz, Phillip L. Covell, Martin Doll

A series of difficult ground conditions causing high groundwater inflows and hazardous gas intrusion abruptly halted the construction of a 6.4-meter (21-foot) finished diameter and 1,890 meters (6,200 feet) long tunnel planned to serve as a 4-millioncubic meters (1-billion gallon) per day capacity river outfall for treated wastewater. Some 808-meters (2,650-feet) section of the constructed tunnel, TBM, and all other tunneling equipment were completely flooded with hydrogen sulfide laden artesian groundwater. The subsequent pumping and tunnel recovery efforts were unsuccessful and the tunnel was abandoned. In the end, the construction contract was terminated and options to redesign and reconstruct the project were re-evaluated to maximize the use of already constructed tunnel facilities such as the construction access and inter-mediate shafts and six outfall diffuser shafts in the river.

Jan 1, 2007

By Marianne Snedeker

In January we published a questionnaire asking about the content of MINING ENGINEERING and about your interests. At the same time we hired an outside firm, READEX Inc., of St. Paul, MN, to send the same questionnaire to a sampling of about 1000 US members, selected on an nth name basis, so that we could have some preliminary numbers for the Annual Meeting in February. READEX sent us the final results of its survey in March. At that time, 525 responses of the 992 surveys sent out had been returned, for a 52.9% response, an extraordinarily high return for a low-key (no incentive for return) random sampling. On May 7, we cut off on tabulating returns from the magazine so that we could report the results to you in this issue. At that time, we had 594 questionnaires returned. Our 594 and READEX's 525 (we have assumed that relatively few people returned both), represent a 1119 return, about 3.5% of the approximately 32,000 who received the January issue of ME. About ME Through responses to the questionnaire, we were hoping to learn more about you, your interests, and how the magazine could better serve you. Those of you who responded, told us something positive-you look at or read the magazine. Of the 1119 respondents, 1068 or 95.4% indicated that they had read or looked through the November and/or December issues. Those of you who refer to the magazine once are 466 or 42.6%. Those of you who refer to the magazine two or three times are 559 or 51.1%. Those of you who refer to the magazine four or more times are 68 or 6.2%. How much time do you spend reading the magazine? Of those responding to this question: 186 spent up to 1/2 hr 16.6% 590 spent up to 1 hr 52.7% 292 spent 1-2 hr 26.1% 51 spent more than 2 hr 4.6% In an informal survey among our staff, we determined that most people spend 1/2 to 1 hr reading magazines to which they subscribe at home. Does that match your experience? Many of you, 764 or 69.4%, clip your magazine for further reference. Also, many of you, 513 or 64.2%, do not pass your copy on to another reader, indicating perhaps that you are clipping it or receiving the magazine at home. Those magazines that are passed on reach: 2 people - 159 - 20.0% 3-5 people - 95 - 11.9% 5 or more - 31 - 3.9% Answers to what portions of the magazine you find useful indicated that the top three were Industry News, feature articles, and Technical Papers; see Table 1. The "other" category included advertising-display, classified, and employment-Coming Events, product information, Washington Survey, new books, the reader service card, and Engineering Fundamentals. Of those responding, 797 or 75.3% indicated a preference for dual notation of SI (metric) with English units; 228 or 21.5% preferred all SI units; while 34 or 3.2% preferred SI with dual notation of other metric units. Based on the preliminary numbers reported by READEX for this question, the MINING ENGINEERING Committee in February voted to return to a policy of dual notation. This decision has been implemented. We asked for your appraisal of the technical level of the magazine. Of those responding, 78 or 7.4% indicated it is too technical, 147 or 13.8% indicated it is not technical enough, and 836 or 78.8% judged it to have the correct tech¬nical level. In response to the question about whether you like to read an occasional feature that is not technically oriented, 32 said no, but an overwhelming 97% (1024) said yes. Of the specific topics, 785 like history, 558 political or socioeconomic articles, 440 career development, and 373 human interest. Other topics suggested included new disciplines, mineral resources of the world by

Jan 6, 1982

By E J. B van Etten

Pit lakes may form when open cut mining leaves a pit void that then fills with ground and surface waters. This often replaces terrestrial ecosystems that existed prior to mining with an aquatic ecosystem, affording an opportunity to improve regional aquatic biodiversity values through targeted aquatic restoration (McCullough and van Etten, 2011). Restoration theory provides guidance when restoring disturbed systems towards landscapes that are of regional value and relevance. But how do we identify a restoration target for a novel aquatic habitat that only exists in the new post-mining landscape? This paper presents a process of first identifying and then surveying local representative aquatic systems, to provide a direction for pit lake restoration efforts and achievement criteria for pit lake relinquishment, using a case study from a sand mining operation amongst wetlands in south-western Australia.The company mines silica sands following mechanical removal of topsoil and then extraction of the ore from below the watertable by dredging. Assessment of wetland and riparian vegetation was achieved through the establishment and measurement of temporary monitoring transects across five natural wetlands in the Kemerton area. Several more regional wetlands were also visited and observations made to supplement and validate these data.Distinct vegetation zonation was found across each wetland, although typically wetland basins were unvegetated or filled with younger woody plants with patchy distributions. Fringing riparian vegetation consisted of few species (commonly the paperbark Melaleuca rhaphiophylla and the sedge Lepidosperma longitudinale), but community composition and structure were variable between wetlands. The pattern of vegetation seen across natural wetlands was best explained by topography and soil chemistry, with low lying wetland areas more likely to experience regular flooding and accumulate organic matter and nutrients.In conclusion, where they are available, regional natural waterbodies may constitute the best valid restoration goal. Nevertheless, the goal may need to consist of a range of closure design opportunities, rather than a single target.

Oct 5, 2011

By Thomas C. Shapiro

This is the second in a series of articles on microcomputers and applications in the minerals industry. The first article (ME, Feb., page 129) discussed microcomputer terms and concepts. This article will discuss software for geology and mining. The third article will cover plant, administrative, and geotechnical software applications. Introduction Geology and exploration are areas where computers have a natural fit. Large volumes of data need to be tabulated, evaluated, and made into maps and reports that allow geologists and management to make a decision on a project or mine. Until recently, the programs that performed these tasks were cumbersome and not user friendly by any stretch of the imagination. Learning time to become an expert in these programs typically would be six months or more. The computers needed to run these programs are expensive mainframes. Several years ago, the use of minicomputers became popular because of their lower cost. Programs were adapted to fit these smaller machines and became friendlier. With the advent of micros, many programs. were rewritten and used the screen capability more effectively, thus providing a real advance in user interface. Programs and Price The definition of micro, mini, and mainframe is becoming blurred. For the purposes of this article, micro refers to either an eight- or 16-bit computer, costing less than $10,000 and, more typically, under $5,000. Mini refers to a 16- or 32-bit computer that typically costs more than $25,000. Mainframe refers to a 32-bit or larger computer that costs more than $250,000. There is a large gray area between micros and minis, and minis and mainframes. Technology and prices are changing so fast that the traditional definitions have become almost meaningless and price has become a better guide. With the arrival of the minicomputer, costs for hardware began to fall, but the programs have tended to remain unfriendly. In some cases, the minicomputer acted as a front end to the mainframe. Cost of both the programs and minicomputers could easily run a minimum of $70,000. A total cost of $200,000 would not have been out of line. The average geologist and company would have a great deal of difficulty justifying such a purchase. The advent of the microcomputer has changed all that. For $3,500 to $5,000, one can buy a 16-bit micro and a printer. Plotters with six pens are available for $2,000 that will produce a 280- x 430-mm (11- x17-in.) map. For several hundred dollars, software is available to act as a word processor, an economic spread sheet, or to perform ground water calculations. In fact, some programs are available for free. Some of these programs are relatively easy to learn. In addition, programs are being developed daily that are easy to use. More importantly, large programs that once ran only on mainframes are being converted

Jan 3, 1984

By John J. Vieaux

Allowable loads on Dynamically-Cast-In-Place Piles (the Franki type) can be correlated with N values from the Standard Penetration Test. Using a constant developed by Nordlund, a conservative value for load-carrying capability of a DCIP pile is developed. The DCIP pile and method of installation is briefly described.

Jan 1, 1984

By D. W. Holliday

The major deposits of anhydrite and secondary gypsum in Jamaica occur discontinuously at a single horizon within the Lower Eocene succession of southeast Jamaica. They are not intruded from other horizons of different age, as has previously been supposed. The gypsum and anhydrite occur in a regressive sequence at the junction between marine (Richmond Formation, Halberstadt Volcanics, Halberstadt Limestone) and overlying non-marine (Wagwater Formation) sediments. They are thought to have been formed in an arid supratidal (sabkha) environment. A variety of 'nodular' structures occurs in the gypsum and anhydrite which can be related to early diagenetic processes and compaction effects. All gradations exist between single isolated anhydrite nodules and structureless anhydrite due to closer packing and coalescence of nodules. The structures and textures in the anhydrite are thought to be consistent with penecontemporaneous formation from gypsum crystals rarely more than 2 cm in diameter. Single anhydrite nodules are not usually larger than 2 cm; nodules of greater size are compound, due to the coalescence of several smaller nodules. Some large compound nodules may have developed from single sand crystals or rosettes. Compaction of anhydrite appears to have been largely mechanical, but some rocks have an aligned fabric, suggesting later flowage

Dec 1, 1971

By Fred C. Schmednecht

For years, the strategy was to contain waste and in many applications, is still the recommended method. Recently, it has become acceptable to create filters below ground for the in-situ treatment of waste. Consequently, in lieu of the waste being contained, it is desirable that the waste flow through a pervious treatment zone. For instance, subterranean pervious walls comprised of iron sand are particularly useful in treating chlorinated solvents in contaminated groundwater. The iron acts as a corrective filter to treat the contaminated groundwater. How are these impervious and pervious walls being constructed? One effective means of constructing an impervious barrier is the vibrated beam method. This method, in brief, involves the use of a fabricated steel beam, a vibrator, a pile driving crane, and a mixing plant. This method results in a 4-6" wide wall with depths up to and exceeding 100'. Over one hundred slurry walls have been installed using this method in the United States. The need for the vibrated beam method continues to escalate due to its reduced health and safety considerations, high level of quality control, lack of excavation, narrow working area, and ability to achieve depths greater than 100'. A recent project was in Marinette, Wisconsin at the ANSUL facility. The project consisted of a 28,000 square foot slurry wall and was completed in January of 1999. Another effective means of creating an impervious barrier, where structural support from the barrier is needed, is the Waterloo® Barrier System. This system involves the use of a pile driving crane, Waterloo® steel sheet piles which are patented steel sheet piles due to their groutable interlocks, and a grout plant. This system results in a water-tight barrier due to the grouted interlocks and provides structural support. A project was completed at Beta Steel in Portage, IN for a retention pond to protect Lake Michigan. Due to the new concept of "filtering", there are few accepted construction techniques available. One effective field proven construction technique is the patent pending mandrel emplacement technique. This technique involves the use of a fabricated hollow steel mandrel with a shoe, a vibrator, a heavy duty crane, and a material feeder. This technique results in a pervious wall which may be comprised of pure iron sand or any other flowable media. Using this technique, the pervious wall may be constructed in varying widths to depths in excess of 100'. A successful installation occurred in October 1997 at Cape Canaveral Air Station in Florida.

Jan 1, 1999

By A. R. Barnes, A. F. Newall

Keywords: Pyrometallurgy, furnace, smelting, spinel, PGM, phase diagrams As Merensky reef ores are replaced by UG2 ores, chromium levels in PGM smelting furnace feeds have steadily increased. Increased chromium levels lead to operating problems. Attempts to increase the chromium solubility in the slag by a variety of techniques create other difficulties. The authors have developed a technique for removal of the chromium spinel interface along with the matte for subsequent separation outside the smelting furnace by utilising differential solidification in the ladle. The process has been patented internationally with support from the Innovation Fund.

Jan 1, 2006

By P. Condori

Palabora Mining Copper has a unique ore body composition which unlike other copper ore bodies has three main components in significant proportions; these are copper bearing ore, magnetite and dolerite. The high content of dolerite, a hard barren material, creates a high proportion of pebbles which normally are recycled back to the mill. This action increases the mill bearing pressure and power progressively until corrective actions are taken. A logical action to solve the pebbles generation would be to incorporate a pebble crusher. This in fact was done however two fundamental issues were encountered; the high content of magnetite and existence of a cyclone classification section. Due to the high content of magnetite, metal detectors have not been able to work efficiently to separate tramp metal which causes damage to the pebble crushers. The existence of cyclones in the circuit had a detrimental effect on the final product when the pebbles crusher was online producing coarse sandy material. Due to the difficulties in treating pebbles via conventional procedures and the unique Palabora ore composition and characteristics, sorting technology was investigated at laboratory and pilot scale. It was found that a combination of optical and electromagnetic sorting could efficiently separate dolerite from the copper bearing and magnetite ores. This paper reports the findings of the laboratory and pilot scale work performed and discusses the additional benefits to the circuit.

Jan 1, 2012