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By R. M. Zimmerman

INTRODUCTION Tuff is being considered as a possible geologic median for the underground storage of commercial high level radioactive wastes by the Department of Energy (DOE). DOE has the responsibility for developing or improving the technology fir safely and permanently isolating these wastes. DOE programs must satisfy requirements established by the Nuclear Regulatory Commission (NRC) for the licensing and regulating of these storage facilities (NRC 1981). Pertinent draft NRC requirements are: 1) releases of radioactivity to the environment must be within prescribed limits and 2) emplaced canisters containing wastes must be retrievable up to 50 years following emplacement. High level radioactive wastes produce heat in storage and it is essential that the thermal/mechanical/hydrological response of the host rock will not significantly degrade either the structural performance o£ the repository or the ability of the natural or engineered barriers to retard radionuclide migration. The Nevada Nuclear Waste Storage Investigations (NNWSI) was established by DOE to evaluate the suitability of disposing of high level nuclear wastes on or near the Nevada Test Site (NTS) (NNWSI 1980). NNWSI has focused exploration and site evaluation on the tuffs of Yucca Mountain. Field testing is essential to support site characterization and repository design efforts. Preliminary studies have been conducted indicating that tuffs in G-tunnel on the NIS contain welded and nonwelded tuffs that have similar properties to those in Yucca Mountain. Thus, field testing can be accelerated. This paper discusses the issues supporting the planned field experiments in G-tunnel. Issues not related to rock mechanics are not included.

Jan 1, 1982

By P. B. Knuckey, D. Littleford

The Kalengwa mine, situated in a remote area of Zambia in Central Africa, has presented some unique problems to the planners engaged in developing the deposit. This small, high grade copper deposit contains some 1,688,000 tons of ore at a grade of 9.3% contained copper. Of this 362,000 tons is classified as high grade ore at 27.2% Cu, the coarse fraction of which can be fed directly to converters; 733,000 is classed as intermediate grade ore averaging 6.3% Cu, and 593,000 tons classed as low grade ore containing 2.1% Cu. The geology of the deposit and the establishment of the mining operation is fully described. A concentrator is being built at Kalengwa to treat the high grade fine product, intermediate, and low grade ore, whilst the coarse high grade ore will be trucked to the Copperbelt smelters for direct smelting. Details of metallurgical processing are given. The decision to truck the coarse high grade ore to the smelters on the Copperbelt necessitated the construction of a new 200-mile road, the setting up of a fleet of heavy ore transport trucks and associated equipment. The remoteness of the area from established communication facilities on the Copperbelt necessitated the provision of radio communications between Kalengwa and the head office at Kalulushi, and the establishment of a regular mine air service. The paper also describes the training of an unsophisticated local population in the operation of heavy plant and machinery, the establishment of the township, and the provision of health services.

Jan 1, 1972

By E. A. Noble

In the Western Coal Region, successful reclamation of surface-mined areas includes the protection of groundwater sources. To accomplish this, a complete understanding of the geohydrology of the affected area is imperative. Successful mine design also calls for careful attention to geohydrology. Because the Western Coal Region is semi-arid land used mainly for farming and grazing, groundwater is a particularly sensitive topic. It is especially sensitive where the lignite scheduled for mining is itself the aquifer supplying the farms and ranches. Such is the case throughout much of the Western Coal Region, particularly where there are no near-surface sand and gravel aquifers that are commonly found in the glaciated portions of the Region. Just as mining can adversely affect groundwater supply, so can groundwater adversely affect mining. Mine flooding and highwall instability are examples of this. But, mine operators must realize that procedures they use to remedy geohydrologically-related mining problems can have a dramatic effect upon ground- water conditions in areas adjacent to the mine. A logical precaution is to require the acquisition of complete baseline data prior to making the first cut. We recommend that the mining plan not only incorporate the reclamation plan, but that they be developed as one plan.

Jan 1, 1976

Carbon-concentration Meter The latest of these, the ultrasound-based carbon concentration meter, was developed by Mintek with original sponsorship by the Chamber of Mines Research Organization, and is now being manufactured and marketed worldwide by Debex Electronics in Johannesburg. Testing of detonators* The Chief Mining Engineer has asked the South African Bureau of Standards to monitor locally manufactured, as well as imported, detonators. This could ensure greater safety in fiery mines.

Jan 1, 1990

By W. T. Plummer

• The SuperBowl is a fluidized bed, semi-continuous, enhanced gravity separator for gravity gold recovery. The market for this type of equipment has, until recently, been dominated by a single supplier. Many mineral processors have encouraged the SuperBowl designers to develop competitive equipment for obvious reasons. • The primary beneficiary of competition in this field will be the mineral processing community because legitimate competition fosters continuous improvement in product and price.

Jan 1, 1996

By B. H. Sandelowsky

Prehistoric metal-working in South West Africa by B. H. SANDELOWSKY*, Ph.D. (Visitor) This paper describes a three-hundred year old metal-working site at Rehoboth, and makes a plea for information on such sites elsewhere in South West Africa so that they can be investigated. The technique of ore smelting that was used at Rehoboth appears to be different from that practised elsewhere by Bantu peoples before the modern era.

Jan 5, 1974

By K. C. Ko

The pit slope angle dictates the economics as much as the depth of the pit. Steeper slope provides more ore reserves, at the same time, the steeper slope presents higher probability of instability and associated maintenance problems. While large open pit mines mostly belonged to nonferrous metals in the past, other mines are becoming deeper as the mine economics permits deeper mine operations, Such minerals include coal, uranium, phosphate, and others. There are some basic differences between an open pit slope and slopes that are encountered in usual civil engineering work such as dam embankments and highway cuts (Figure 1). The stability of the civil engineering slope changes continuously with time due to ground-water movements, weathering, etc. But the stability of the open pit slope (Figure 2) changes more drastically day-to-day or even hour-to-hour, These changes occur because not only is the slope geometry being continuously changed by the mining operation, but also different geology and geologic structures are being exposed on the slope. Even when a particular slope area is not presently being mined, excavation in adjacent areas can affect the general condition of that slope area. A pit will experience some slope failures during its life.

Jan 1, 1977

By George A. Morrison

THE Columbia Chemical Division of the Pittsburgh Plate Glass Co. is at Barberton, Ohio, 35 miles south of Cleveland. For many years large tonnages of limestone have been brought to the Barberton plant from distant points. The stone is here burnt in vertical kilns, the resultant product then hydrated and the hydrated lime used in chemical processing. To eliminate the expense of these shipments, the company decided to investigate a limestone bed known to exist on company property at Barberton, where the stone is used. The bed lay at a depth of more than 2000 ft. and was known locally as the "Deep Lime." Chemical analyses of sludge from churn-drill holes made some years ago proved that the limestone was of sufficient purity to warrant diamond-drill exploration. Four diamond-drill holes were put down at well-spaced intervals, to represent fairly an area of four miles by one mile. Cores logged as to chemical and physical conditions were found to compare closely, and to corroborate the earlier evidence that the limestone was of superior quality for chemical use. A plant of 300 tons per hour was subsequently decided upon. SITE The yard at the chemical plant was already so congested that location of the projected mine within its area could not be considered. Eventually a site was selected 2 miles northwest of the plant, near the main line of the Erie Railroad. Here 412 acres were owned outright by the company and stone rights were obtained on 250 additional acres. This location required a transportation line of nearly 2 miles (8800 ft.), crossing two major highways, and to avoid interruption of deliveries to the plant, overpasses were planned. GEOLOGY The limestone in the immediate vicinity lies about 2200 ft. below the surface. Geologists* identify this stone as Delaware of Devonian age. It is overlain by 18 ft. of unconsolidated (sand and gravel), 100 ft. of water-bearing sandstone, and finally 2080 ft. of shale into which sandstone in thin layers is interbedded. The contact of shale and limestone is abrupt, flat-lying and very pronounced. Berea sandstone, often found at 520 ft., is absent, but Euclid sandstone was encountered, together with a seepage of oil and a small amount of methane gas. The limestone bed itself is 345 ft. thick, and overlies 200 ft. of gypsum. The lower part becomes dolomitic as it approaches the gypsum. A detailed study of the drill cores indicates that the upper 50 ft, are highest in lime and reasonably low in silica. The physical make-up shows several separating cherty layers. These occur at definite horizons and cause distinct partings, which become horizontal planes of

Jan 1, 1943

By Dal Negro Enrico, Andrea Picchio, Boscaro Alessandro

"The Doha Metro Project is one of the most relevant ongoing tunneling projects. The whole project consists of about 100 km of tunnels with 21 EPB TBMs working in the same period. Due to the variability of the geological formations, the soil conditioning is a relevant aspect of this project because the parameters should be frequently adjusted to achieve the best performances of the TBMs. The study of the soil conditioning has been carried out accurately to obtain the best results on site. The study of the geotechnical data, the choice of the most suitable foaming agents and polymers and the laboratory study of the soil conditioning has been a fundamental part of the job. The application of the soil conditioning products on site with the analysis of the TBM data have confirmed the preliminary study results with some correlation between the features of the ground and the soil conditioning parameters to be used. INTRODUCTION Phase 1 of the Doha Metro Underground project is composed by 3 lines able to bring passengers to all the points of interest in the Qatar capital city. The Red Line, also called coastal line, connects the north of the city to the south, and to the new Hamad International Airport, following the coast line. The Golden Line, called Historic Line, will connect the southern area of Doha to the “Aspire zone” the area of the city where many state of the art sport centers are located, passing through the old city center. The Green Line, named education line, will connect the old city center to the Doha Education City. All the lines are realized with 2 tubes, single track. The whole underground project is realized with 21 TBMs, excavation diameter of 7.10 m. The project has been divided in 4 packages, for a total excavation length of more than 100 km. The need to underpass roads, existing buildings, and to excavate, in some areas, at less than 100 m from the coast line, forced the choice of a tunneling system with Earth Pressure Balance (EPB), that involves in the project another fundamental aspect of this tunneling system: the soil conditioning. The soil conditioning has multiples functions in the EPB system such as to make the soil suitable to properly apply the pressure on the tunnel face and to be extracted effectively with the screw conveyor. To properly study this topic it was necessary to study the geological formations to be excavated, the hydrogeological conditions of the underground, the foam injection systems of the EPB TBMs and to perform specific tests to evaluate a suitable conditioning to be verified and adjusted during the real scale application."

Jan 1, 2016

By Martin Mayers

IT has long been recognized that it would be highly desirable to be able to predict the temperatures at various points in a burning fuel bed and their variations with changes of the properties of the fuel and the rate of air supply. Experimental investigations of fuel-bed tempera-tures1-4 have not been lacking, but the absence of any theoretical back-ground has made it impossible to use the results of these tests as a basis for prediction, except in a very general way. A mathematical analysis5, based on a somewhat simplified theory of the distribution of heat in a, fuel bed, has recently been completed by the author. Even though numerical values of some of the coefficients are not. known, the calcula-tions result in some conclusions of general significance. Thus, for example, it appears that when the temperatures throughout the fuel bed can be calculated, the rate at which ignition of the fuel by underfeed action can be maintained can also be calculated. The uncertainty concerning the values of the coefficients referred to above is a serious limitation on the use of that method. The following paper presents a discussion of these coefficients and includes estimates of their values based on the data now available. A brief description of the theory on which the analysis is based, and some results of the calculations showing their degree of agreement with experimental results, are presented by way of introduction to the discussion of, the coefficients. For a more extended discussion of the theory, see the A.S.M.E. paper5.

Jan 1, 1937

By Michael J. Taylor

Introduction A prime goal in the design and operation of uranium milling waste or tailing disposal systems is to mitigate adverse effects of tailing liquid on the adjacent groundwater. Adverse effects are often defined as modifying the groundwater quality in such a manner as to have detrimental health effects on downstream users. To accomplish this goal, the following three types of systems are employed with regard to the seepage and groundwater aspects of waste disposal: Type I Systems Seepage is allowed to occur unabated from the tailing disposal facility. Detrimental radionuclides and chemical elements are prevented from causing adverse downstream effects by natural purification actions in the subgrade geologic materials and the near zone groundwater. Monitoring is required to assure the predicted natural purification is occurring. The consequences of seepage loss is minimal since the m be predicted with current investigation and analytical techniques and can be evaluated as to effectiveness during operations. Type II Systems Seepage is partially retained in a waste impoundment or leakage from a designed retention system is anticipated. Natural purification is relied on for controlling migration of detrimental radionuclides or chemical elements, or contingency planning is employed to collect and return the tailing liquid to the impoundment. Installation efforts and concern for escape of tailing liquid are greater than for Type I systems, but extra precautions to preclude all seepage are not implemented. Monitoring is required to detect leakage and/or assure the natural purification of escaping tailing fluid. The consequence for accidential excusions are moderate, and will be excessive only if massive system failure occurs. Type III Systems Seepage is totally restricted by a costly system constructed and operated with extra care. Natural

Jan 1, 1980

By Paul F. Kerr

Uranium mineralization occurs in the footwall of the Sunshine vein from the 2900 to the 3700 level. Veinlets of uraninite associated with pyrite and jasper have been so extensively divided and recemented that units more than a few feet in length are seldom observed. The wall rock is St. Regis quartzite of the Belt series. The age of the uraninite, on the basis of isotopic analyses, is 750 t- 50, which agrees with geological data suggesting that phases of the Sunshine mineralization are pre-Cambrian.

Jan 5, 1953

By U. S. Kusel

Extractive metallurgy in Iron Age South Africa U. S. KUSEL, B.A. Hons. (Pta) (Visitor) The finds relating to the metal-working of Iron Age Bantu tribes are reviewed, the following metals or alloys being considered: gold, tin, copper, bronze, brass, and iron. Most is known about copper- and iron-working, but even this is very little, and no one has successfully been able to demonstrate how iron was smelted in the primitive furnaces that have been found.

Jan 1, 1974

By Henry A. Russell

During the last ten years Parsons Brinckerhoff has become a leader in the area of tunnel rehabilitation. A significant part of any tunnel rehabilitation program is the control of groundwater infiltration into the structure. This leakage over time, causes deterioration of the structures, and creates numerous operational problems for the tunnel operator. This paper will address current procedures for identification, documentation, and recommendations of repair methods for the control of groundwater infiltration in rail and highway tunnels.

Jan 1, 1993

Although the 'exi'stence of bauxite in Australia has been known for many years it is only recently that exploitation has commenced.. of the two most' important` deposits, strangely at almost diagonally opposite tips of the continent. Recognition of the importance. of the bauxite in the South/West corner came about initially through the efforts of a well-known Australian mining company which,` with some outside financial help, tackled the early exploration with commendable foresight and courage.

Jan 1, 1964

By C. W. Spencer, R. A. Rummel, F. N. Rhines

SPECIMENS of five cast Cu-Bi alloys, containing 4.68, 0.53, 0.043, 0.0064, and 0.0025 wt pct Bi and cast pure copper were subjected to a bend test to determine their relative ductility. Using metallo-graphlc methods the structures of the fractured surfaces were compared with those of the polished cross sections. Embrittlement was found to be associated with the presence of a second phase in the grain boundaries although, in the lower bismuth

Jan 1, 1958

By Vicki Seppala

Phelps Dodge Mining Company operates some of the world’s largest open pit mines. Safely mining in these deep pits requires the commitment to a proactive integrated slope management process. The slope management process also includes the continued look for improved slope design, construction, and maintenance of slope faces. This paper discusses integration of such technology as electronic programmable detonators, 3D imaging using ground-based LiDAR scans, and reflectorless slope monitoring systems in a slope management program.

Jan 1, 2005

By O. Garg

This paper summarizes the computer applications in open-pit mine planning at the Iron Ore Company of Canada (IOC). A brief history of the use of computers at IOC is given, and a description of the existing facilities is outlined. The following systems are discussed: storage and retrieval of geological data; geotechnical data analysis; long-term grade and tonnage forecasting; ore grading; and open-pit mine design. Justification for using computers in open-pit mine planning is given, and possible future areas of application are considered.

Jan 1, 1979

By Claude Cunningham

AEL’s Electronic Delay Detonators are in routine use and growing in both volume and breadth of application in Africa. This trend will continue and grow internationally owing to increasing pressure on rockbreaking operations to conform to sustainable development principles. A fundamental breakthrough has been achieved, bringing production blasting into line with technologies, which leverage performance through tight monitoring and control. When moving from pyrotechnic systems, benefits are normally realized without having to adopt different timing patterns, but significant additional benefits are realisable by using the flexibility and precision of the electronic units to enter windows of timing previously closed. The higher price and increased care needed are a worthwhile investment, enabling operations to cross the chasm to stronger revenues, but the system must be robust and suited to the application and personnel. Economic models are vital for keeping track of the potential and achieved benefits of these systems. Some resistance can be expected from those who stand to lose income as a result of the improved efficiencies.

Jan 1, 2004

By W. H. McCormick, H. J. Benecki

CONSIDERING that a typical modern drilling machine strikes approximately 2000 blows per min and may develop a force of 30 to 200 ft-lb, de- pending upon size of the drill used, the importance of uniform stress distribution in this type of drilling becomes obvious. If the rod were perfectly symmetrical, and if it did not rotate, the problem would be relatively simple, however, the necessary forging, machining and heat treating operations prevent attaining this state of perfection. Take the modern hollow drill rod. The blow is transmitted not from the striking end of the rod directly through to the point of impact of the bit in the rock, but rather through a somewhat complex tool. To add further problems, this entire assembly is rotated immediately after the impacting blow. Rather than attempt to discuss the magnitude and distribution of stresses, it is desired to present a few things that will minimize unusual stress concentration and produce a rod in which the stress distribution will approach the theoretical ideal.

Jan 3, 1954