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By Richard Kastner, Emilie Vanoudheusden, Fabrice Emeriault, Jacques Robert

INTRODUCTION The subway line B of Toulouse (France) has been realized with three different tunnel boring machines (TBM) techniques: Contracts 2 and 5 are excavated with earth-pressure balanced TBM, Contract 4 with a slurry shield TBM, and Contract 3 with a compressed-air TBM. The first three machines are around 7.7 m in diameter, while the last one is 5.3 m. Moreover, a small part of the line (50 m) has been excavated by a conventional method. The tunnels run through the Toulouse molasses, composed of hard sandy clay with pockets and lenses of dense sand. Geotechnical investigations have shown that in these formations, K0 is greater than 1, around 1.8 at a depth of 25 m (Serratrice,2005) and that geotechnical characteristics are homogenous on the whole layout (? =22 kN/m3, Su = 300 kPa, c' = 30 kPa, F' = 32°). The water table is found between 2 and4 m below ground level. As geology, stratigraphy and tunnel cover (between 10 and 20 m) are almost identical, a comparison of movements induced by the excavation by each of the four excavation techniques is possible. This paper presents the soil mass movement measures in the case of the conventional excavation method and in the case of TBM sections. It shows how tunneling parameters may explain the different surface movements observed during excavation. For the sake of simplicity, only the results of Contract 2 (earth pressure balanced TBM)will be presented. MONITORING Monitoring for the Conventional Method Section For the conventional method section (Vanoudheusden et al. 2005) the mass soil movements are measured with two inclinometers and one multi-point extensometer borehole with automatic data acquisition (Figure 1). The monitoring devices include

Jan 1, 2007

By L. R. Stace

Arguably, one of the most significant technological breakthroughs that had been experienced during the period when British Coal was the major coalmine operating company in the UK, the use of rockbolts as principal support in underground roadways brought with it the need to re-assess the technical knowledge, management controls and legislative frameworks associated with the support of mine workings. Following a major roof fall in a roadway supported principally using rockbolts in which fatalities occurred, the process of the design of rockbolted support and the systems and procedures that had been put in place to control its use in the UK were further reviewed. The paper discusses the outcome of these reviews, and how the incident initiated a major new interest in strata control research in the UK against the background of the fragmentation of the ownership of the mines following the sale of the former British Coal assets at the end of 1994, together with the proposed introduction of new strata control legislation in 1996.

Jan 1, 1996

By V. C. Kelessidis

The interaction between rock and drill bit during drilling has been modeled for many years, but a complete understanding of the phenomena occurring has yet to materialize. Successful models will allow the prediction of rate of penetration in a given environment and optimal selection of drill bit and drilling parameters, thus minimizing exploration costs. In most rock-drilling models the value of the unconfined compressive strength of the rock (UCS) is used in the predictive equations, within the concept of specific energy, and the value of UCS is the percentage of the value of the stress applied on the drilling bit in order for the bit to advance. While the exact percentage depends on the model used and it is not known with certainty, good knowledge of UCS is nevertheless required before any decent prediction can be made on rate of penetration. Determination of UCS, normally done via destructive testing, requires not only the availability of sound rock core samples but also expensive testing and significant time for the test, which frequently are not available for routine drillability predictions. Hence, a multitude of methods and techniques has been proposed for estimating UCS from various indirect and/or non-destructive measurements, or combination of measurements with neural networks, such as point load index, block punch index, unit weight, and apparent porosity, water absorption by weight, sonic velocity, and Schmidt hardness. The many proposed approaches are critically reviewed and the results are compared, and what becomes apparent is that after many years, not only in mining but also in oil-well drilling, accurate indirect determination of UCS is still an elusive goal. An equation to predict UCS from sonic velocity data is suggested based on several data sets reported in the literature. Use of the specific energy equation with UCS or sonic data and utilization of drilling data allows an estimation of the efficiency of energy transfer from the bit to the rock and of the friction coefficient. Analysis of data reported in the literature, both from laboratory and field studies, has shown that this approach is sound and enables the determination of energy transfer efficiencies and friction coefficients, which for the cases studied range between 15 and 30% and 0.15 and 0.30 respectively. Thus, the suggested data analysis approach allows drillers to focus on inefficiencies and optimize drilling practices in future campaigns. Keywords Rock drillability, unconfined compressive strength, prediction.

Jan 1, 2011

By Yvone Franco Crosato

The dense population of Hong Kong requires the construction of tall buildings in reclaimed areas or perched on the slopes of the many hills. The large loads to be supported are carried by deep foundations. Many of those are bored piles, to rock, of diameters up to the 3.0 m. of today.

Jan 1, 2000

That electricity is an important and valuable agent, the limit of whose capacity for utilisation is as yet unknown, is a truism; although enormous advances have been made, the possible developments are yet greater. Mining, along with other industries, shares already to a large extent in the practical utilisation of this agent. Electrical engineers have been employed for several years past in developing and applying electricity to all classes of machinery, and for every purpose where power is required and in no instance, that the writer is aware of, has its use been curtailed in favour of any other agency now known, while extensions are continually made. The first modern electric motor was shown at the Vienna Exhibition of 1873, and it was used to work a pump through a mile length of cable but it was not before 1878, that an electric motor was put into daily commercial use by Messrs. Chretian and Felix to work a beet sugar hoist. This early plant effected a saving of 40 % as compared with hand work.In 1879, the first Electric Railway was constructed for the Berlin Exhibition, and in the same year, Mr. T. A. Edison was running an experimental line at Menlo Park. The first electric line opened for the public, was constructed by Siemens and Halske, in 1881, at Lichtenfelde, and was 11 miles in length.

By Wolfgang Guetter, Wolfgang Weber

The upgrading project for two hydropower plants in Slovenia, Europe, requires two new pressure tunnels: Plave II (5.9 km Flysch) and Doblar II (3.6 km Limestone). It is the worldwide largest application of the Double-Shield TBM technology combined with an extremely thin-walled monoshell honeycomb lining system. The first drive has been completed by end of June 2000 achieving best performances of 50m/d and almost 1,100m/mth. In September 2000 the TBM started the second tunnel without any required adjustments due to geological or other reasons. Another 52m/d have been bored already within one production day of two 8 h shifts achieving a maximum penetration rate of more than 6m/h. The completion of the Doblar drive can be expected by February 2001.

Jan 1, 2001

The Bureau de Recherches Geologiques et Minieres (BRGM) (a French Government-sponsored geological and mining agency), through international experience gained over many years, has become very skilled in alluvial prospection, particularly for diamonds. The research laboratories within the BRGM have also been active in creating new mineral processing equipment, some of which is directly applicable to such prospection. One such development, the mobile prospection unit, is described and its application in mineral exploration is demonstrated by a consideration of the diamond search in Australia and the general exploration of the Massif Armoricain (France). Because this latter study was fundamental in the development of the concept of 'mineral-geochemistry', and its application in mineral exploration, it is also briefly described.

Jan 1, 1971

By Robert H. Robinson, Levent Ozdemir, Russell J. Miller

The paper summarizes an investigation into the applicability of mechanical excavation to oil shale mining; identifies available machine types that are best suited to various aspects of the mining operation; presents preliminary comments on the configuration of an "IDEAL" oil shale mining machine; and establishes the background information necessary for conceptualizing and evaluating new mining methods using mechanical excavation equipment. Conclusions are also presented as to the best currently available systems, as well as potential future systems.

Jan 1, 1983

The preeipitation of dissolved lead from a strong brine by metallic iron is a chemically controlled, first order reaction. The precipitation rate is sensitive to changes in chloride concentration and temperature. The precipitation of dissolved silver is a diffusion controlled, first order reaction. The precipitation rate is insensitive to changes in chloride concentration and temperature.INTRODUCTIONLead and silver sulphates can be extracted from electrolytic zinc plant tailings, or residues, by leaching with strong brine solutions, the lead and silver going into solution as complex chlorides. One of the methods which can then be used to recover the dissolved lead and silver is to precipitate them with metallic iron. The deposition reactions which take place are of the type Pb++ Fe - Fe++ Pb............ (a)To fit such a method of precipitation successfully into a practical flowsheet it is necessary to have some knowledge of the kinetics of the various reactions, Le. to know how the precipitation rates vary with temperature, brine and metal concentrations, and so on. Reaction rates are also needed to design suitable precipitation vessels. However, when examining the possibility of using a brine leaching process to extract the lead and silver from the residue produced at the Risdon plant of the Electrolytic Zinc Co. of Australasia, it was found that, although the use of metallic iron to recover lead and silver from the pregnant brine had been reported by Ralston (1924) and by TrumbulI, Hardiek and Lawford (1948), very little was known about the precipitation reactions. Consequently a laboratory investigation was undertaken, and this paper covers those aspects considered to be...

Jan 1, 1961

By O. Noirot, H. C. Owens, P. D. Rao, D. E. Walsh, J. R. Mokka

Over a period of seven years (1989-1996) the Mineral Industry Research Laboratory (MIRL) University of Alaska Fairbanks, has investigated the effects of temperature, residence time, and particle size on the degree of low-rank coal (LRC) upgrading for a non-evaporative, hydrothermal drying process, also known as hot water drying (HWD). Three Alaskan LRCs were used in this study: Usibelli coal (Seam No. 4) from the Nenana Coal Field, Little Tonzona coal from near McGrath, and Beluga coal from the Beluga-Yentna field on the west side of Cook Inlet. Replicated, factorial tests were conducted. Experimental results indicate that most of the low-rank coal upgrading via HWD occurs rapidly within the first 10-20 minutes of residence time. Thereafter, the upgrading process slows down and over 100 minutes of additional residence time are required to produce similar percentage increases in coal properties to those achieved in the first 10- 20 minutes. The properties of the hot water dried products were very sensitive to process temperature. Calorific value, carbon and oxygen contents, equilibrium moisture levels and Hardgrove gindabilities all appear to change linearly with temperature within the 275°C to 325°C range.

Feb 24, 1997

By S A. Myers, T Klein

The Yanacocha mining district is located in the northern Andes of Peru. The project is within the Cajamarca province, 20 km north of the town of Cajamarca and 600 km north of Lima, the capital of Peru (Figure 1). The district encompasses an area of 120 km 2 and is centred on the 78030'west longitude and 7000' south latitude. The project lies at an elevation of 3400 to 4200 masl.

Jan 1, 1999

The development of research activities at Risdon and the implementing of a policy of instrumentation in plant processes have, in recent years, entailed a considerable increase in research staff and created an urgent need for more space and modern laboratory facilities. The existing laboratories have been in use for 25 years and are now inadequate. New buildings have been authorized.The new buildings will comprise, firstly, a laboratory building of three floors giving a totai .floor space of approximately 11,000 sq.ft., and a pilot plant building as an annexe to the laboratory building, of approximately 4,900 sq.ft. The laboratory building will accommodate from 20 to 22 research workers, and additional plant operatives will be used for the control of processes in the pilot plant building. The new buildings are designed to provide facilities for three principal functions; the investigation and improvementof existing processes, the development of new processes up to the pilot plant stage, and the control and maintenance of instruments.LOCALITY AND ORIENTATION OF BUILDINGSThe site of the buildings is elevated ground on the eastern side of the main plant, near the main entrance and general office building. There will be no obstruction to sunshine at any time of the day, and the laboratory building will command views of wide radius from wooded hills across the River Derwentto the open sea on the south-eastern quarter.The buildings are located to provide space for future extensions. The main laboratory building faces approx...

Jan 1, 1949

By D. Rendini, R. D. Gutridge

INTRODUCTION Gwinnett County, Georgia, is a part of the rapidly expanding metropolitan Atlanta Georgia area. Located approximately 48 km (30 miles) northeast of Atlanta, Gwinnett County has a current population in excess of 600,000 and is projected to reach a population of 1,200,000 by 2025. As a part of the County’s master plan to supply drinking water for the expanding population and to increase system reliability, the Gwinnett County Public Utilities Department undertook the Shoal Creek Raw Water Intake and Pump Station Project. Figure 1 shows a vicinity map for the project. Prior to construction of the Shoal Creek Raw Water Intake and Pump Station Project the County had a single raw water intake to feed water from Lake Sidney Lanier (Lake Lanier) into a filter plant for processing into potable water. This project together with a newly constructed water filter plant provides Gwinnett County additional capacity and system redundancy to prevent interruptions to the drinking water supply. Lake Lanier is a man made reservoir with over 800 km (500 miles) of shoreline and was constructed by the Army Corps of Engineers in the 1950s for hydro electric power generation, flood control, and navigation benefits for the Chattahoochee River. Over time, Lake Lanier has become an increasingly important source of drinking water for the metropolitan Atlanta area. This paper focuses on the primary underground construction and lake tap components of the project including a 42.7 m (140 ft) deep pump station shaft 24.4 m(80 ft) in finished diameter transitioning to a 6.1 m (20 ft) finished diameter shaft, a3.05 m (10 ft) finished diameter by 19.8 m (65 ft) deep intake shaft constructed in an average of 21.3 m (70 ft) of water, and a 190.5 m (625 ft) by 3.05 m (10 ft) finished diameter modified horseshoe tunnel connecting the two shafts. This raw water intake system, in conjunction with the incorporated pump station with 8 pumps and dual1,829 mm (72 inch) pipelines, provides a system capacity of 1,091,062 m3/day(240 MGD) to two water filter plants and is expandable by the addition of pumps to1,500,210 m3/day (330 MGD). Parsons provided design and construction management services for the project. The $29.6 million contract to construct the project was awarded to W.L. Hailey &Company. Notice to proceed was given August 6, 2001 and substantial completion was achieved on January 20, 2004. Value engineering changes adopted for the project contributed to completing the project at a final cost of $28.8 million.

Jan 1, 2005

By Peter Florian

At 5:50 am on October 1, 1992, the new $800 million Pittsburgh International Airport Midfield Terminal opened its gates to the world after five years of construction and more than 24 years of planning. Despite numerous design changes, this massive project was completed on time and substantially within budget. The importance of this airport to Allegheny County and the Pittsburgh region was recognized 24 years earlier by Allegheny County Commissioners Tom Foerster and the late Leonard Staisey. Staisey and Foerster established a program to acquire land for the "Airport of the Future".

Jan 1, 1993

By Jerry Gagnon, Matt Burr, Dave Evans, Timothy Ellis, Davies Kakengela, Abbas Mirza, Larry Webb, François Leclercq, Andrew Johnston

Lead-based alloys are the primary anodes used in electrowinning from sulphate-based aqueous systems. Lead anode technology has evolved over the years, migrating from pure lead and lead-antimonial alloys to the present day lead-calcium-tin alloys for copper electrowinning and lead-silver alloys for zinc electrowinning. It has also migrated from cast to rolled microstructures in search of improved mechanical properties and higher corrosion resistance. Although great strides have been made in the development of new alloys and production processes, the industry still has unresolved issues related to untimely corrosion which limits anode life and may lead to higher contaminant levels in the metal being produced. Lead anodes corrode because of the difference in the chemical/electrochemical potential across the microstructural features of an anode. Given a very high purity material, we find that the grain boundary areas corrode significantly faster than the rest of the grain. The desire to minimize grain boundary corrosion by a balance of alloying element selection and microstructural design allows the grain boundary area to be engineered. However, operational issues can lead to unexpected corrosion behaviours which we will discuss moving forward. The comments in this work, though directed toward copper electrowinning, can be extended to similar phenomena in other metals electrowon from sulphate media (i.e., zinc, nickel, cobalt, manganese). The lifecycle of electrowinning anodes is dependent upon electrowinning tankhouse operating conditions and maintenance of the anodes, including cleaning and straightening. This paper will focus on the operational aspects of maximizing the utilization of lead electrowinning anodes.

Jan 1, 2015

By M. E. Tyrrell

Research objectives were to determine the reasons for erratic behavior of semisilica horizontal zinc retorts in service; to investigate potential corrective measures including the possible utilization of more refractory materials in the retort body; and to delineate laboratory tests suitable for process control in the manufacture of retorts. Correlation of laboratory test results and data supplied by the cooperating smelters indicated that structural failures due to thermal shock and laminations in the retort body are largely responsible for the erratic behavior of horizontal zinc retorts in service. The most promising modifications made in the retort body and evaluated on a laboratory scale included finer grinding of the plastic clay fraction, substitution of mullite grog for calcined fire clay and grain alumina for silica, plus the use of an organic binder. Lamination-free extrusions having excellent thermal shock resistance were prepared from a mixture composed of 50 percent low-silica Missouri plastic clay through 100 mesh, 25 percent mullite grog through 6 mesh, and 25 percent alumina through 100 mesh. The mix was pugged under 28-inch vacuum with 1 percent ligno sulfonate binder in 12 percent tempering water. Laboratory tests suitable for process control in the manufacture of retorts are described.

Jan 1, 1969

The reduction of zinc from slags by a molten, carbon-saturated bath was examined in a laboratory study under conditions of continuous slag feeding. The results show that it is possible to reduce the bulk of the zinc from the slag before there is a net reduction of iron. However, the recovery of zinc was not as high as in batch tests performed in an earlier study. Lead in the slag was reduced simultaneously with the zinc to very low levels and was volatilised. Copper in the slag was reduced and dissolved in the alloy. An attempt was made to identify potentially commercial ways of treating zinc slags using an iron bath. The approaches that appear to have the greatest potential are reduction in a batch process using electrical heating and reduction in a continuous process with co- or countercurrent flow of the slag and alloy. In the latter the alloy would be prepared in a separate furnace before being contacted with the slag. The purpose of this would be to superheat and carburise the alloy so that no additional heat or reductant would have to be supplied in the slag-alloy reactor

Jul 1, 1991

By J. -P. Saindon, L. D. Nel, A. E. Hall, S. G. Hardcastle

"This paper reports on an investigation into gas and dust concentrations in Ruttan Mine's exhaust air. The values obtained indicate that there is excellent potential to recirculate approximately 25% of the hot exhaust air into the intake air to reduce winter heating costs. Contaminant concentrations vary significantly during the course of the working shift and decrease in the mine exhaust system as the air returns to surface. A proposed on-line control system is outlined which would permit recirculation to be implemented with a pay-back period of less than two years. IntroductionIncreased energy costs and depressed mineral prices have resulted in mines, which use winter ventilation air heating, reviewing their systems to try to reduce costs. Heating costs can be significant, for example, Potash Corporation of Saskatchewan spends an average of $580,000 per mine per year and Ruttan mine spends approximately $IM per year on propane for its direct-fired heating system.Several method s of reducing heating costs have been considered and the following have potential application.Heat Exchange Between Exhaust andIntakeThis is usually accomplished by run-round glycol systems. The system is limited by ice formation on the coils in wet exhaust air and by the low exhaust air temperature, usually l0ºC. It also requires close proximity of the intake and exhaust airways to ma~e the cost of the connecting pipeline and pump systems economic . A feasibility study by Inco's Thompson operation reported that a proposed system of this type had a 19-year payback period and was, therefore, uneconomic. Potash Corporation of Saskatchewan is currently investigating plastic heat exchangers for a trial system because of corrosion on metal exchangers. It has the advantage of a 17°C exhaust temperature and relatively dry exhaust air.Waste Heat ReclamationThe waste heat from compressors and hoists can be used for heating in some mines. The feasibility of such a system depends on the individual layout and the proximity of the heat source to the inlet airway. Other mines have considered using the exhaust air in greenhouses to provide a cash crop."

Jan 1, 1988

THE method depends upon:--1. The position of the mill.2. The space available for stacking the residue.3. The nature of the residue as discharged from the mill.4. The value of the residue for re-treatment.5. The requirement of the residue for underground filling.Originally the conditions in this district varied mainly in the position of the mill, some mills having an elevated site with plenty of dumping space for the time being, whilst others had a flat site, and very little dumping space near at hand; but in most cases the residue discharged was in the form of filter-press cakes, suitable for conveying on belts, or in trucks, and stacking in a high clump; and, while a portion of the residue was used for underground filling, the dump was regarded as a valuable asset, to be re-treated later. Under these conditions, conveyor belts, electric trams, aerial trams, and hose trucks, all gave satisfactory results, and the following figures, taken from "'West Australian Metallurgical Practice," will show how these methods compared as regards costs...

Jan 1, 1909

Research personnel from the Bureau of Mines, a representative of the Mine Safety and Health Administration, and research contractors for the Bureau of Mines met with other Government and industry representatives at three seminar locations in December 1980 to discuss the findings and products of Bureau research on mine safety training. The research program is aimed at providing assistance to the mining community in its efforts to reduce industrial-type, human-error accidents through research establishing performance based methods and media for employee training. Research emphasis is directed toward development of baseline materials and instructional models; development of methods for structuring and evaluating health and safety, supervisory, and occupational training; and the continued investigation and application of current learning and simulation technology that could significantly enhance the effectiveness of training opportunities.

Jan 1, 1981