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By Robert J. Auber, Thomas R. Scotese

The West Leg Interceptor is part of a new sanitary sewer system in the southwest suburbs of Cleveland. The first two construction contracts were excavated in glacial soils varying from hard tills to pressurized silts and flowing sands. These soil and groundwater conditions were locally problematic during shaft and tunnel excavations and final lining construction. A variety of solutions were developed primarily during construction. During the WLI-1R Contract, subgrade pressures, continued ground losses, and displacements necessitated extra eductor wells and modified inverts for stabilization of shafts. At the WLI-2Contract, one shaft excavation in similar ground required only one extra well. In the WLI-1R tunnel, localized inflows of groundwater, silt, and sand through the geotextile fabric were stopped by cement grouting. In one WLI-2 connector tunnel, damage to the TBM flood doors combined with wet, flowing silt and sand led to ground losses, surface settlements, plugging, patching, and chemical grouting. The concrete lining in the main WLI-2 tunnel required remedial work to improve watertightness at joints.

Jan 1, 1999

By Robert Turner

Gold and silver processing techniques are some of the oldest in the mining industry. Gold mining of high grade veins and deposits has existed for centuries. However, only with the higher gold prices in recent years and heap leaching techniques have the low grade gold and silver deposits become feasible to mine and process economically. By mining and hauling 3,600,000 tons of ore per year at an average grade of 0.03 ounces/ton gold and 0.385 ounces/ton silver, the Zortman- Landusky operations became profitable in 1982. To maintain profitably, a stripping ratio of less than one ton of waste to one ton of ore, and mine run ore placed on the leach pads which will yield approximately seventy percent go1 d recovery.

Jan 1, 1984

By D. G. Feuerbacher

Maximizing production of oil from sandstone petroleum reservoirs is aided by use of non-damaging drilling and workover/completion fluids. Various tests, such as X-ray diffraction, scanning electron microsccpy, petrographic microscopy, porosity and permeability are conducted on core samples. Several fluids are selected, on the basis of these results, for return permeability tests. A report is then written giving the results of all tests, potential reservoir problems, and recommended practices for exploiting the reservoir.

Jan 1, 1983

By Y. J. Wang

The definitions of system pressure loss (mine head) and system resistance, which are traditionally associated with single-fan net- works, are applied to multiple-fan ventilation networks. The system characteristics -- relations among air power, pressure loss, air quantity and resistance -- are analyzed by introducing the concept of subsystems. These subsystems are associated with the fans located in a cutset of the network. For a multiple-fan network, the resistances for the subsystems and total system are dependent on the quantity ratios of the subsystems. In general the pressure loss of a subsystem or a total system does not vary as the square of the corresponding air quantity. If the quantity ratios of subsystems are all held constant, then the resistances become constant and the pressure losses are predictable from the quantities employing the "square law." The system resistance has a minimum value under the natural- splitting flow pattern. Being independent of the value of system quantity, the minimum system resistance provides a basis for comparing the different networks.

Jan 1, 1983

By Charles G. Weakly, Alan M. Lander, Pamela B. Zohar, Robert W. Leonardson

The cluster of gold deposits at the Goldstrike property is located in the Northern Carlin Trend in northeastern Nevada (Fig. 1). At many mature mining camps like Goldstrike, exploration innovation and success may wane with time. In this regard, sufficient exploration drilling was conducted in the area immediately north of the ultimate pit crest and under the final planned pit wall to test for a major deposit. No indications of large deposits were found, however, the majority of drill holes did intercept mineralization. Mining along the northern pit wall exposed significant structurally controlled ore-grade mineralization that had been missed by exploration drilling. In 2002 and early 2003, the mine geology group added reserves to the pit and improved the definition of underground resources by targeting specific ore-controlling structures within favorable stratigraphic units by utilizing relatively inexpensive horizontal RC drilling from the pit wall. The widespread occurrence of mineralization to the north of the pit was re-interpreted to be an indication of continuity of these mineralized zones. In January 2003, 70 feet of 0.332 opt Au at a depth of 710 to 780 feet was intercepted in a dewatering well. This intercept was significantly thicker and higher-grade than average for the area, which confirmed the existence of high-grade structural continuity, and helped secure management support for additional exploration. A timely and cost effective solution was needed to confirm the potential of the area. Immediate follow-up drilling on tighter grid spacing was rejected in favor of improving the geology model. Exploration across the property would benefit from an improved geology model, but to provide results in a timely manner, the area to the north of the Betze pit was chosen as a starting point (Fig. 2).

Jan 1, 2005

By Phillip J. Maddex

Transportation is a major part of yours in the industrial minerals industry. Whereas federal income taxes merely take 50 per cent of your firms profits, transportation cost may take 50 per cent of the gross realization - selling price plus transportation - on your product, f. o. b. customers plant.

Jan 1, 1969

By Stephen R. Hunt

This paper summarizes some preliminary results of the Illinois State Geological Surveys current investigation into surface subsidence resulting from coal mining in Illinois. The purpose of the study is to characterize-the vertical movements that may result from various types of underground coal mining. In general there is relatively little published information about subsidence from room-and-pillar mining as compared with longwall mining. The findings of this study, based on mining operations in a variety of geologic settings, delineate the magnitude, shape, and position of the subsidence profile. Comparisons of case histories of subsidence are based primarily on the extraction ratio and the general geometry of the mine (depth, panel width, and mining height).

Jan 1, 1979

By Dean H. Herrick

The production of crushed stone in the United States has exceeded 1.0 Gtpy since 1987. Eighty percent of the crushed stone produced is used in the aggregate industry, accounting for over half of the quantity of natural aggregate consumed in the United States. Approximately 718 of the crushed stone produced in 1989 was limestone and dolomite followed by granite, traprock, sandstone and quartzite, miscellaneous stone, marble, shell, calcareous marl, volcanic cinder and scoria, and slate in order of descending volume (Table 1). Of the remaining 20% crushed stone produced in the United States and not used as aggregate, 12% is used in the manufacture of cement which is an important construction material. Only 8% of crushed stone is used in specialty products not associated with the construction industry. Therefore, this chapter will concentrate on crushed stone as used in aggregates, with occasional reference to other uses or to chapters which discuss specific nonconstruction uses of crushed stone. Construction aggregates are hard, essentially inert materials suitable for being formed into a stable mass by the addition of cementing or binding materials that produce a concrete by compaction, or by natural weight to produce a road or foundation fill. Aggregates are usually from 80 to 100% of the material volume of the construction masses in which they are used. Conditions necessary for a rock deposit to be developed for construction crushed stone include: Quality-should pass rigid specifications for strength and durability; Quantity-adequate volume of rock is needed to have a production life of at least 10 years, preferably 20 or more years; Market-must have adequate market to support a new crushed stone operation; Transportation-transportation cost must be competitive for the intended market; Environmental-the impacts of mining, processing and transportation of crushed stone on the environment at or surrounding the mine site must be within acceptable limits; Permitability-mining, processing and transportation of crushed stone must usually be permitted by governing agency. The following discussion will touch upon all facets of crushed stone operations from the mineral deposit and its geology to technology, uses, economic factors and end with governmental regulations of mining crushed stone. The sections are not designed to answer all questions, but rather to be an introduction to the crushed stone industry. Where more information is required, The Aggregate Handbook by Barksdale (1991) is recommended as the best general source.

Jan 1, 1994

By L. Tondo, W. Lim

The high pressure grinding rolls (HPGR) is a relatively new technology which offers the potential benefits in energy savings, circuit simplicity and improved product characteristics in minerals processing applications. Over 300 machines are now operating world-wide, but most of these are used for grinding cement clinker, and relatively few are used in conventional mineral processing. One of the rea- sons for its current limited use in the minerals processing industry is that design, scale-up and flowsheet assessment procedures are seen to be relatively immature and untested. This has reduced confidence in the potential application of the technology. To help rectify this situation an industry funded research project was undertaken, one of whose aims was to develop and prove a mathematical model of the HPGR and a scale-up procedure. Data were collected from tests using laboratory, pilot and in one case a full scale unit (2.2m diameter). A range of feed types were tested including quartz, limestone, kimberlite, bauxite, iron ore and gold ore. These data were then used to develop models of the size reduction performance, power draw, throughput and operating gap for a wide range of pressures, feed sizes, and roll speeds. This paper describes the models that have been initially developed and illustrates their accuracy using some of these data.

Jan 1, 1998

By Kailash Narayan

Atlantic Richfield Company began operating a commercial uranium solution mining project in April, 1975 in Live Oak County, 10 miles southwest of the town of George West (Figure 1). The operation is designed to produce 250,000 pounds of U303 per year and is jointly owned by Atlantic Richfield Company, Dalco and U. S. Steel. The proprietary process employed in this operation consists of injecting an alkaline leaching solution into the ore-bearing formation through a pattern of injection wells. The uranium-bearing solution is then removed through producing wells using submersible pumps in central production wells. The produced solution is pumped through a pipeline to the plant area where the uranium is extracted. The barren solution is refurbished and returned to the pattern area for reinjection. The injection field and plant site are located in the drainage of Spring Creek, a small intermittent stream tributary to the Nueces River. Land use in the area is primarily agricultural -- cattle ranching and farming -- but several producing gas fields are present in the areas as well.

Jan 1, 1976

By Larry Sevenker

On the basis of favorable salt characteristics, primarily compressive strength and impermeability, solution-mined cavities can provide structurally stable isolation chambers for waste. Solution mining techniques are established for storage of hydrocarbons. The proposition of waste isolation in engineered salt cavities is similar to this practice relative to characterization, certification and safeguards. What materials are isolated and how operations are conducted are principle differences. Compatibility of wastes with other wastes must be considered, but hazards can be precluded by avoiding certain mixtures. Waste material characteristics and cavity considerations are discussed.

Jan 1, 1981

By Guy Reed, Russell Frith

In situ or pre-mining horizontal stresses are arguably the least well understood of the principal inputs into underground coal mining geotechnical engineering design, whether analytical, empirical, or numerical. This is a direct result of both the cost and difficulty of obtaining meaningful stress measurements, the various limitations of the measurement method in terms of sourcing strata types that approximate the assumed conditions of the post-measurement mathematics to convert measured strains into stresses, and a common practice by some geotechnical professionals to preferentially utilise generic values rather than interrogate the available measurement data for cause and effect relationships between horizontal stress magnitudes, directions and a range of associated controls. That numerical modelling simulations attempt to mimic reality but often rely on simplified generic horizontal stress input assumptions is a particular cause for further consideratio The paper attempts to further explore the nature of in situ horizontal stresses using a range of stress measurement results from the Australian coal sector supplemented by several international studies addressing the same basic issue, the result being a number of credible and highly relevant “cause and effect" inter-relationships between the three principal in situ stresses in addition to the influence of rock properties (e. Young's Modulus and Poisson's Ratio), cover depth and the larger-scale structural geological environment. In particular, the paper demonstrates that despite being commonly overlooked as a primary rock/coal material property, Poisson's Ratio and the associated K Effect are intrinsic to understanding 3D in situ stress measurement results and therefore, predicting in situ stress magni- tudes more generally for geotechnical analyses purposes. As a fundamental question, the paper addresses whether it is necessary and of engineering value to characterise in situ horizontal stresses: according to distinct "domains," in the same way that more easily identifiable geotechnical properties such as rock mass ratings, coal seam thickness, ply splits, and cover depth are often treated.

Jun 25, 2024

By S. M. Khandrika

It is shown that dewatering of fine coal particles (D50 : 21 microns) is enhanced near the point of zero charge. The coal surface is modified by the addition of copper ions and adjusting pH to precipitate surface active metal hydroxy species which promote agglomeration and produce low moisture cakes. Filtration kinetics data are used in calculating filter cake parameters from an integrated form of Darcy's law. The influence of copper ions and pH on filter cake parameters and correlations among them are presented.

Jan 1, 1993

By G. T. Lineberry, R. S. Mateer

Often only after years of "technical dormancy" do errors in published literature become apparent and meaningful. To prevent duplication of effort for future generations, the fol¬lowing corrections are offered. These errors were discovered during a recent study in which a computer program for mine hoist rope selection was developed (Lineberry and Mateer, 1988). In order of increasing gravity: Captions for Figs. 3 and 4 are transposed. • Purported to be a more accurate method of rope selection than the process of successive approximation, the direct method assumes linearity between a given rope's minimum breaking strength, T, and unit rope weight, Wv. Because of the sensitive location of the constant, K, in equation (8) for breaking strength, the significance of this nonlinearity is magnified. For a typical 6 x 37 class fiber core wire rope (Wire Rope Corp. of America, 1985), K actually varies from 43,650 to 52,190, depending upon rope diameter. Although the direct solution permits a rapid selection of hoist rope, an indirect (iterative) solution procedure is favored because of its im¬proved accuracy and ease of computerization. • Equation (8) for minimum breaking strength is in error. It should read:

Jan 1, 1989

By G. T. Lineberry, R. S. Mateer

Often only after years of "technical dormancy" do errors in published literature become apparent and meaningful. To prevent duplication of effort for future generations, the following corrections are offered. These errors were discovered during a recent study in which a computer program for mine hoist rope selection was developed (Lineberry and Mateer, 1988). In order of increasing gravity: Captions for Figs. 3 and 4 are transposed. Purported to be a more accurate method of rope selection than the process of successive approximation, the direct method assumes linearity between a given rope's minimum breaking strength, T, and unit rope weight, WV. Because of the sensitive location of the constant, K, in equation (8) for breaking strength, the significance of this nonlinearity is magnified. For a typical 6 x 37 class fiber core wire rope (Wire Rope Corp. of America, 1985), K actually varies from 43,650 to 52,190, depending upon rope diameter. Although the direct solution permits a rapid selection of hoist rope, an indirect (iterative) solution procedure is favored because of its improved accuracy and ease of computerization. Equation (8) for minimum breaking strength is in error. It should read:

Jan 1, 1990

By Paul Soros

A major share of the increase in the energy demands of Ontario province in the next decade will be supplied by bituminous coal mined in the U,S, To be competitive with alternative sources of energy, it is essential that the delivered cost of coal, inclusive of all transportation charges, be kept at a minimum. The Bessemer aid Lake Erie Railroad Company and the Pittsburgh and Conneaut Dock Company are currently building a shiploading terminal at Conneaut, Ohio, to service this tonnage, together with expected increases in coal consumption in the Eastern Lake Erie - Lake Ontario area, (see Fig, 1).

Jan 1, 1965

By T. H. Phillips

The Mission Mine is an open-pit copper mine located 18 miles south of Tucson, Arizona in the eastern foothills of the Sierrita Mountains. Mining is done on 40 foot benches using P & H 2100 shovels and 170-ton Terex trucks. Drilling is accomplished With two (2) Bucyrus-Erie 45R?s, one (1) Bucyrus-Erie 60R and two (2) Ingersoll Rand T-5?s. For secondary drilling. a Joy VCR-ISO truck mounted drill is used. The mine is currently operating 3 shifts/day, 7 days/week at 59,100 tons per day, with the mill receiving 28,500 tons per day. The management of the drilling and blasting program requires extensive record keeping in all phases of the operation. This is essential in order to evaluate different products and procedures.

Jan 1, 1988

By Kerry Burns

Contrary to active subsidence, which occurs concurrently with mining operations, or is completed within a few days following coal extraction, delayed subsidence may take many years to appear at the surface after coal mines are abandoned. There are two principal morphological types of delayed subsidence: troughs, which are shallow depressions, and sinks, which are steep-sided crown pits. Both types are damaging to surface structures, and a variety of methods have been introduced to deal with the problem, ranging from subsidence insurance to site restitution. In planning insurance or restitution measures, a predictive model is of value in estimating the magnitude of the problem and the size of long-term budgetary commitments. Only one model is known, which was developed for the Bureau of Mines by GAI Consultants of Monroeville (l,2,3). The GAI model is presented in qualitative terms. This report develops a formal basis for the model and tests a numerical implementation on one of the best-described study areas, Allleqheny County in Pennsylvania.

Jan 1, 1982

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

The tungsten carbide insert bit has probably advanced blasthole drilling more than any other single improvement. Tungsten carbide inserts have longer life, maintain sharper edges, and penetrate faster than hardened steel edge bits. Before the tungsten carbide hit appeared, all-steel bits were used. Even with the new bits, blasthole drilling costs vary with the type of equipment used and its condition; the hole's length and diameter; the rock's texture, hardness, and nature; the operator efficiency. To help reduce drilling costs, the operator should be familiar with the use and care of drill bits. This article provides information about tungsten carbide rock bits used for percussion drilling. Consideration of tungsten carbide rock bits includes looking at bit materials [ ] as well as bit operation and maintenance. Two basic tungsten carbide rock hits are the button bit and the four-wing carbide insert bit. Three common hit-to-drill-steel connections are the bottom drive, tapered drive, and shoulder drive. Bottom drive bits arc typically used for singlepass or longhole drilling, with all percussion drills from handheld sinkers to heavy track drills. Tapered socket bits are available with shallow or deep carhide inserts, for the lowest cost depending on the rock type being drilled. Shoulder drive bits are available in all-steel or carbide insert design.

Jan 12, 1981