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By Herbert H. Einstein, Edward C. Tse, David B. Ashley

INTRODUCTION Decision-making in the design and construction of underground facilities must be made under conditions of varying geologic uncertainty, uncertainty which can have a major cost impact if not properly regarded. Of the two approaches for dealing with this variability, preparing for the "worst" anticipated conditions and optimizing design and construction in-situ, preparing for the "worst" conditions is the more if not solely conventionally practiced method in the United States. While the conventional approach is recognized at times to be extremely overconservative, it will remain preferred until a more adaptable method is shown to be economically superior. This paper presents research aimed at providing just such answers as to when and if an adaptable tunnel design and construction approach is more cost effective than a non-adaptable one. To fully understand the characteristics of this choice between adaptable and conventional tunneling alternatives a summary discussion of adaptable methods is presented. An acknowledgement of the importance of geologic and other factor uncertainties in making this decision leads to the adoption of decision analysis as a quantitative methodology for formalizing the problem. Exercising this methodology on three prototypical tunneling scenarios--urban deep, urban shallow, and transmountain--allows an isolation and ranking of the most crucial factors in making the basic approach decision. One scenario, a transmountain highway tunnel, is carried further through a detailed probabilistic analysis to show under what conditions of varying uncertainty adaptable approaches possess economic advantages.

Jan 1, 1979

By S. F. Hillis, J. E. Rourke, K. A. Szalay, O&apos

INTRODUCTION For the past 25 years, tunnel support requirements have frequently been determined, at least in North American practice, by classifying the rock according to the system proposed by Terzaghi (1), using one or more of the 8 Rock Conditions which he defined, the rock load then being selected within the range given for each Condition. However, there is a lack of published data comparing Terzaghi loads with actual measured rock loads, and it would appear that the degree of conservatism, or otherwise, of the Terzaghi approach is very often unknown. Excavation of 4 large diameter tunnels at the Tarbela Dam Project in Pakistan afforded an opportunity to compare Terzaghi and measured loads, through instrumentation of the steel ribs installed for temporary support, and by classification of the geology exposed during the tunnelling operations. In addition, the deformation of the rock surrounding the tunnels was monitored during excavation by means of borehole extensometers installed prior to the start of tunnelling. This paper describes the tunnel instrumentation and the results obtained therefrom, and relates these results to the Terzaghi load coefficients. It also discusses the effects of the methods of excavating the tunnels on the rock loads and rock deformations. PROJECT DESCRIPTION The Tarbela Dam Project is located on the Indus River in

Jan 1, 1974

By T. H. Udayashankara

Soil pollution, a very serious environmental problem, has been attracting considerable attention in recent years. It is now generally recognized that land as a component of the environment deserves the same attention and protection as water and air. This recognition has arisen perhaps because of increased incidents of land pollution, the scarcity of land, and increased awareness and concern about long-term effects of land pollution on terrestrial and aquatic eco-systems and on ground water quality. Contamination of land results from a wide range of human activities, including industrial discharge process, disposal of wastewater and agriculture. The environmental impact of exploration, production and refining of crude oil is a major concern in developed and developing countries. Because of the known adverse effects of petroleum hydrocarbons on soil ecology and fertility there has been growing interest in the development of efficient technologies for the remediation of contaminated land, with a view toward making it available for further use. Crude oil is a natural product and as such is susceptible to degradation by naturally occurring micro flora. Bioremediation has become an important method for the restoration of oil-polluted environments. A bench scale study was conducted to evaluate the bioremediation technique in treating soil contaminated with transformer oil. The steps involved in this study are: (1) Preparation of contaminated soil, (2) Extraction of PAHs and PCBs from contaminated soil, (3) Treatment of contaminated soil in slurry batch reactor, and (4) Analysis of PAHs and PCBs by gas chromatography technique. The performance of reactor was assessed by measuring parameters like COD, PAHs and PCBs. The study was con-ducted for six different pulp densities ranging from 20% to 40%. The maximum removal of PAHs and PCBs was observed for 20% pulp density.

Jan 1, 2008

By E. Turner

This is the 3rd Paper in a series by this author, the first two being published at the two previous International Conferences. Since the Aachen Conference, Rio Tinto has carried out an extensive benchmarking exercise to see how we are positioned with respect to other leading companies (in our sector and other sectors of major economic importance). We need to be sure that Rio Tinto is at the forefront of best practises in Sustainable Development (SD) and is using the most effective tools and methods. This paper will present key findings from this work. Rio Tinto Minerals, working as representatives of IMA-Europe was a leading contributor to the European Commission DG Enterprise Voluntary Reporting Scheme for SD Indicators in the Non-Energy Extractive Industry. In Rio Tinto Minerals we have been using these SDIs in the management of our business and the paper will report on how they contribute to the management of our business and the paper will report on how they contribute to business value in: deepening customer relationships, eco-efficiency of operations, land use planning and permitting for new and expanding facilities, community relations, policy engagement with government authorities and strengthening the bond between the company and employees. We continue to support the Voluntary SDI Reporting Scheme, considering it to be important in the expanding EU and as a model for other regions globally. For example we have ore suppliers in developing countries and we use these SDIs in assisting them to better their performance, for we have an obligation to use our influence for continuous improvement. The paper will describe this work. Over the last 12 months our company has created a new Industrial Minerals unit called Rio Tinto Minerals which brings together all the borates, talc and salt operations, R&D, marketing, sales and customer care worldwide. The paper will present also the new Sustainability Policy of Rio Tinto Minerals.

Jan 1, 2007

By R. Hiebert, M. Canty, S. Beckman

An innovative biological process is described for the treatment of cyanide-, metals- and nitrate-contaminated mine process water. The technology was tested for its ability to detoxify cyanide and nitrate and to immobilize metals in wastewater from agitation cyanide leaching. A pilot-scale demonstration is described in which a pilot plant was constructed to demonstrate the technology on a mine process-waste stream at a mine in Nevada. The demonstration was performed jointly under the Mine Waste Technology Program (MWTP), funded by the US Environmental Protection Agency (EPA) and jointly administered by the US De¬partment of Energy's (DOE) Western Environmental Technology Office (WETO) under Interagency Agree¬ment Number DW89938513-01-0. The Superfund Innovative Technology Evaluation (SITE) demonstration program was also involved in the project. MSE Technology Applications Inc. (MSE), Butte, MT, was the contractor responsible for conducting the project, and Pintail Systems Inc., Aurora, CO, was the technology provider. The pilot-scale unit was field-tested at Echo Bay's McCoy/Cove Mine southwest of Battle Mountain, NV. The biotreatment process was considered successful in destroying cyanide in the mine process water. The process was also determined to be effective in removing metals. The pH was consistently neutralized and nitrates were successfully removed from the mine process water. From the results of these pilot-scale tests, it was concluded that the biotreatment process potentially of¬fers an innovative, cost-effective alternative for the treatment of mining wastewaters.

Jan 1, 2000

By Oleg N. Tikhonov

A new extraction method which includes a combination of gravity and alternating electromagnetic fields with interfriction of mineral particles was proposed (Tikhonov O.N., 1979) and tested in lab conditions at Mineral Processing Department of St. Petersburg Mining Institute. At the beginning of the work the main goal was to find an efficient alternative to traditional extraction methods (like shaking table, etc.) used for concentration of fine alluvial gold particles. After the method and a series of gradually improved lab separators (Tikhonov, et al., 1983) were positively tested for gold (Tikhonov, et al.. 1986) the efficiency of the method was also proved for extraction of and other heavy minerals from alluvial and ground ores in experimental work at the St. Petersburg Mining Institute. The fine heavy minerals were separated to concentrates with high technological indices (Andreev et al., 1987), (Tikhonov, Gladkov, 1987), (Tikhonov, Gladkov 1989). In parallel a semi-industrial gravi-electro- magnetic separator was made and several technological flowsheets were designed for testing the method in industrial conditions (Tikhonov O.N., Miazin B.N., 1987), (Tikhonov O.N., Tolstunov S.A., Jebelev V.V.,1989). A series of industrial tests accompanied with complete sampling and standard technological measurements were performed at several alluvial deposits, with good technological indices. Thus the method and the flowsheets displayed high additional recovery of fine alluvial gold particles during elkrated industrial experiments in Siberia (Aldan province). At higher concentrate grade this method, even in one-stage operation, increased gold recovery more than by 25% compared with shaking table (for particles -0.10 mm gold recovery was 82% vs. 55% by shaking table, for particles - 0.25mm the recovery was 97.5% vs. 61.8%). Experiments were performed by joint team of St. Petersburg Mining Institute and the Irkutsk Institute of Rare Metals (Tikhonov O.N., Gladkov S.A., Tarasova T.B., 1991).

Jan 1, 1995

By Barbara S. Parrish, I. S. Parrish

For two consecutive years the author and his wife have been fortunate enough to have been invited by the Peoples Republic of China to work with Chinese geologists of the Geological Bureau of the Ministry of Metallurgical Industries (MMI). Our visits, each of which lasted 7-8 weeks, took us to northwestern Sichuan, central Anhui, and much of Hebei Province, as shown in the accompanying drawing. We were asked to evaluate, criticize, and offer suggestions on the exploration and mining techniques used by the Chinese. Our commission both years was centered on gold, although we were also to visit other operations when the opportunity arose. In 1986, the visit primarily concerned with disseminated "Carlin" type gold deposits; in 1987, with "Greenstone" type gold deposits. Gold has been targeted by the Chinese as a metal of importance to the nation. Several governmental agencies have received direction and budgets to seek and develop gold properties. Besides the Ministry of Metallurgical Industry, gold is being sought by the Ministry of Geology, the China Gold Corporation, and reportedly the Peoples Army. There is considerable competition among these agencies. It is not uncommon to find two or more agencies working in the same general area. However, communication between the groups is minimal. Last year, we toured a small mine at Bambishan. We could see a diamond drill across the valley. The rig belonged to another Ministry and my guides voiced their curiosity to know what their competitors were finding. Mining, too, is not the monolithic bureaucracy that most Westerners anticipate in China. There are various levels of mining. These differ not only in sophistication, but in ownership. First, for small deposits the state allows "Peoples Mines". These can be owned and worked by individuals. The individual owner-miner may hire relatives or neighbors and give them a wage or he may turn the mine into a joint ownership situation. They

Jan 7, 1988

By Dinah O. Shumway

California's annual production of >11 million tons of cement, at a value of over $640 million, comes from eight companies, which operate 11 plants. Cement is California's second most important mineral commodity, representing 25% of its total annual mineral production. Although most of the cement produced is consumed within the state, current export locales include the Pacific Northwest, Nevada, Arizona, Utah, and New Mexico. An enumeration of the components required to produce cement is deceptively simple: calcium oxide (65%), silica (20%), alumina (4-5%), iron (3-4%), and calcium sulfate (4%) as a retardant admixture. The last, and most expensive, ingredient in cement manufacture is energy. Detrimental materials in cement mixes include excess .magnesium, alkalis, heavy metals, sulfur, and other volatiles. Each of the 11 cement plants in California requires a unique chemical solution of combined raw materials to produce a uniform product: portland cement. The geologist proposing solutions for the additive raw materials in cement manufacture must have a thorough knowledge of a particular cement plant's needs. In the California cement market, keeping the costs of additive raw materials down is one way to also stay competitive, and using a combination of natural and waste materials as additive raw materials allows cement producers to stay competitive.

Jan 1, 1999

By Bruce Hern

The last 10 years have seen a dramatic increase in the requirements for product coal quality control. This has led to electric utility sulfur scrubbing, metallurgical blast furnace optimization and coal producer blend and yield optimization. To achieve this improved level of control, coal producers are designing facilities that emphasize new technology. New facilities will be designed and existing facilities will be retrofitted with state-of-the-art technology to meet quality control standards that are dictated by the market. The first step in designing for process control requires the identification of those parameters to be controlled and the upsets that can cause variances in the final shipped product quality. The most common parameters that require control are the surface moisture (%), ash (%), pyritic sulfur (%) and gross calorific value (Btu). Total moisture is that moisture that exists on the surface of the particle and is inherent in the particle itself. For the purposes of control, the total moisture is monitored, while surface moisture is controlled. Ash is the inorganic residue remaining after all other constituents are burned away at 75O°C( 1382°F)(ASTM, 1992). Sulfur is the amount of total sulfur that exists either as pyrite (FeS2), inorganic sulfate (FeS04), or organic sulfates (C4H4S) (Leonard, 1979). Currently, pyrite is controlled and total sulfur is monitored. The gross calorific value is the amount of heat produced when a unit quantity of coal is ignited under specified conditions. In this case, a l-g (0.03-oz.) sample of coal is ignited in an isoperibol waterbath and the temperature rise of the water bath is observed. The moisture and ash-free (MAF) Btu is relatively constant for a given seam, resulting in the whole calorific value being a function of the moisture and ash levels (Leonard, 1979).

Jan 1, 1994

By D. Raicevic

The presence of residual uranium and other radionuclides in the uranium mill tailings are posing a continuous health concern to the surrounding environment. The slow generation of sulphuric acid from residual sulphide minerals is the cause of persistant dissolution and discharge of many metallic components of the tailings. The most effective long term solution to these problems would seem to be to produce chemically stable tailings. This paper describes two possible answers to the objective: (1) Removal of radionuclides and pyrite from tailings by mineral dressing techniques; some 60 - 68% of the residual uranium, 70 - 75% of the radium, 60 - 65% of the thorium and 95 - 98% of the pyrite have been rejected from the Elliot Lake tailings. The decontaminated tailings contained 0.003% uranium, 50 - 60 pCi/g radium226, 0.01% thorium and less than 0.1% sulphur as pyrite. (2) Preconcentration of radionuclides and pyrite by beneficiation from Elliot Lake ores prior to leaching; applying this approach about 97% of the uranium, 95% of the radium, 92% of the thorium and 98.5% of the sulphides were concentrated in a radionuclide and pyrite concentrates comprising 25% and 8% of the ore, respectively. The preconcentration tailings (waste) produced contained 0.004% uranium, 20 - 25 pCi/g radium226, 0.005% thorium and less than 0.1% sulphur as pyrite. Economic and environmental advantages of both approaches and the leaching of the concentrates are also discussed.

Jan 1, 1980

By Sol Ribakoff

With the utilization of most of the "high dam" sites for hydro-electric power and the completion of most railroad routes, many tunnel contractors were extremely doubtful that tunnel driving would continue to be an important element of heavy contracting. Experience has proved otherwise. The ever-increasing need for rapid transit and for pollution control have generated, and will continue for the indefinite future to generate, a very high level of tunneling activity. At the same time, the costs of construction have traveled an upward curve in the tunnel industry, as in all other types of construction. As a result, Owners, Engineers and Contractors have sought ways and means of constructing more economically through the development and use of labor-saving devices and techniques. The development of mining machines and lasers has contributed tremendously to such economy. Before giving you a contractor's viewpoint on Owner-Engineer-Contractor relationships in tunneling, it may be well to provide some background as to matters which give rise to that viewpoint. Construction contractors in general, and tunnel contractors in particular, have always had to contend with the physical environment in which the work has to be accomplished. However, when a building contractor has constructed his foundation, and certainly after he has "closed in", he deals thereafter with known physical conditions, or at least with conditions which he could reasonably have estimated would occur. Except, perhaps, for the hazard as to earthquakes, he has cleared Nature's threats. A tunnel contractor, however, must give thought to what the physical environment may do to his job, each and every day that he is driving a tunnel. The general consensus among tunnel men is that Mother Nature is much more likely to be murderous than motherly. Without attempting to make too much of

Jan 1, 1997

By V. E. Suter

Anyone with geothermal experience can readily attest that geothermal operations are a natural extension of oil and gas operations. A geothermal company and an oil company need the same type of people to do the same kind of work. In the geothermal industry, geologists and geophysicists define prospects through surface geology, analysis of surface seeps, magnetics, gravity, and resistivity surveys - techniques similar to those used in the petroleum industry. In addition, shallow (250-ft) temperature gradient holes often are used in geothermal operations. Landmen take geothermal leases that are patterned after oil and gas leases. Exploratory drilling is done with the same drilling contractors and same drilling rigs, with minor modification. Drilling foremen and drilling engineers share the same objective of making the most hole, in the shortest time, at the least cost, with a proper completion. Petroleum engineers test the wells, design the completions, determine the reserves, make economic calculations, work with the tax assessor, and manage the reservoirs. Production engineers build roads, locations and pipelines, install gas/liquid separators and meters, and operate production and injection facilities. A contract to sell steam to a public utility is required. Various governmental regulations, permits, environmental concerns, and public affairs pose similar problems in both industries. Also required of both are top management people who are acquainted with geologic risk, prepared to accept million dollar dry holes, willing to bid competitively at lease sales, and able to invest large sums based on a technology not yet fully proven. Successful geothermal development requires in-depth financial ability similar to that required for petroleum development. A high capital investment is required early for leases, geological and geophysical work, and exploratory and confirmation drilling. After

Jan 9, 1980

By Peter Kolitsch, Galyn Rippentrop

INTRODUCTION On April 14, 1994, the joint venture of Kiewit Construction Company and Kenny Construction Company was awarded a 76 million dollar contract for the construction of the New Hampshire Avenue Tunnels in Washington D.C. The Notice to Proceed was given on May16, 1994 and scheduled completion is September 1997. This project is one of five contracts for the Mid-City E Line as part of the Washington Metropolitan Area Transit Authority (WMATA)Greenbelt Route. Once completed, the Mid-City E Line subway tunnels will connect service between the U Street-Cardozo and Fort Totten stations (See Figure 1). The New Hampshire Avenue Tunnels project consists of approximately 6800 feet of twin single track subway tunnels, three vertical shafts, associated utility work and comprehensive restoration work. Section E4b involved two methods of tunneling along the project alignment. The first method consisted of the well known soft ground open face shield driven tunnel and the second method consisted of tunnels driven using the New Austrian Tunneling Method (NATM) . The NATM section of twin tunnels begins at the Buchanan Vent Shaft and proceeds approximately 2630 feet under Rock Creek Cemetery, including the Farragut Emergency Access Shaft and connects approximately 390 feet beyond to the existing Fort Totten running tunnels (See Figure 2). Special considerations had to be given to the portion of the tunnel alignment which passed beneath Rock Creek Cemetery. The analyses and subsequent selection of the tunnel support system were based on anticipated geological conditions and the sensitive tunnel alignment. The New Hampshire Avenue Tunnels project was the second soft ground NATM project in Washington D.C. The first, by no coincidence, was completed at the adjacent Fort Totten Station and Running Tunnels Project by Mergentime/Hochtief, AJV. Currently, on a nearby WMATA jobsite, the J.F. Shea Construction Company has started a third NATM soft ground tunnel. Tunnel support systems were studied with respect to three tunneling methods: •A one-pass system consisting of a bolted precast concrete segmental lining •A two-pass system consisting of an unbolted precast concrete segmen

Jan 1, 1997

By Eric Forssberg, Mats Hallin

INTRODUCTION Evaluation and optimization of mineral processes has been going on since the the first plant started hundreds of years ago. A huge mass of knowledge has been collected since then. The main problem with this type of empirical knowledge of complex processes is that it is very difficult to formulate and document. The methods used for collecting the knowledge is not consistent but-varies with "he person" that does it. In the late 60's and early 70's efforts were made to use computer based techniques to evaluate process performance and to formulate process models for mineral processes. Models were developed, such as the flotation model by R. P. King (1973) which is still used to simulate flotation circuit behaviour. During the 70's. a number of mass balancing packages were developed together with process simulation packages. The industrial sector also made great efforts to develop and utilize computer based systems for process control and evaluation. The expert system that BOLIDEN created in 1974 at the Kristineberg plant was a remarkable achievement considering the hardware (CDC 3600) and the software tools (FORTRAN) available at that time. The main obstacle to successfully implement optimizing computer control of mineral processes was and still is the limited knowledge about the dynamics of complex processes. There are, however. many activities going on in this area today and it seems that the technology is very near a break through. Process evaluation is the most important tool to improve and maintain the optimal performance of a process. Today dedicated computer based techniques are used for fast and reliable screening of the processes. The stages in process evaluation consist of three basic steps: - Data acquisition, manually or by data logging. - Data refining, mass balancing and parameter calculation. - Data evaluation. The refined data can then be used for model construction/calibration and subsequently for process simulation. This paper describes two studies where the techniques mentioned above are used to evaluate and simulate

Jan 1, 1991

By F. Mensah-Dwumah, W. H. Baker, G. W. Clough

INTRODUCTION The practice of injecting chemical grouts into permeable soils in order to stabilize them for tunnel construction is a common procedure in Great Britain, Europe and Japan. In this technique, the grout penetrates the soil in a fluid condition, but hardens or "sets-up" in about one hour due to a chemical reaction. As a result, the soil, is strengthened and made less pervious, and this, in turn, reduces ground surface movements, limits ground water flow, and controls movements of the heading during tunnel construction. It is only within the last five years or so that this technology has been used in the United States. Most of the applications have been involved in the work for the Washington Metropolitan Area Transit Authority (WMATA) subway construction. The experience gained from this work is, in many instances, unique and should serve to guide use of the grouting technology in future projects. This paper documents five WMATA case histories; information is provided as to the soil conditions, method of treatment, reason for treatment, and tunnel performance. Locations of the five projects covered by this study are indicated in Figure 1. All are within the boundaries of the District of Columbia and involve soft ground tunnel construction. Basic information for the case histories is given in Table 1. Tunnel sizes and depths below the ground surface as well as general soil conditions are similar in all instances. The tunnels are about six meters in diameter and are located so that the crown is five to ten m below the ground surface. The soils typically consist of alternating sand, clay and silty sand strata. However, soil stratification details are

Jan 1, 1979

By Nelson R. Shaffer

Secondary minerals, amorphous materials, and biologic entities that form on building stone can cause aesthetically unflattering changes in color and may even result in stone decay. Techniques to determine causes of such changes generally have entailed destructive sampling and often required chemical, thin section, X-ray, or other relatively slow, expensive measurements. We have found that a rapid leach of in-place stone using small volumes (50-100 ml) of very pure distilled, deionized water provides recovery of sufficient dissolved material to help diagnose stone anomalies. Water is sprayed onto the stone and collected in a nonwetting plastic pan. Ion chromatograph analysis of waters thus collected from more than 160 sites showed wide variations in concentration of anions F, Cl, NO3, and SO4. Anion analyses were made in minutes for less than $20 per sample. Cations Ca, Mg, Fe, and Sr also were detected, and analyses might be used to determine mineral sources using equilibrium computer models. Solid particles filtered from the samples can be examined microscopically to provide further information about atmospheric agents affecting the stone. The collected water can even be evaporated to precipitate dissolved minerals. Chloride values in samples rinsed from stone ran as high as up to 17,000 ppm, nitrate to 100 ppm, and sulfate to 1,000 ppm. Limited data also indicate that measurable amounts of fluoride were found in some of the rinse waters. Chlorides were most abundant in areas where the stone has become dimpled or spalled. Nitrates were generally higher near ground level, and sulfate tended to be more abundant in samples taken from higher sites or from sheltered sites. Dark-stained limestone tended to yield less soluble material than clean-looking stone. Leachable elements were higher in samples from urban areas. Most of our data are from limestone buildings, but the technique works on other types of dimension stone, man-made construction materials, and even natural outcrops of rocks. Longitudinal studies show that soluble materials vary through time and are affected by climate. This rapid, in situ leach technique, although still being perfected, shows great promise in the diagnosis of stone alteration and in the evaluation of stone treatments because it is completely nondestructive.

Jan 1, 1999

By Donald G. Wieland, James H. Meinholz

INTRODUCTION The Milwaukee, Wisconsin Metropolitan Area provides an ideal opportunity to review the advancement of the art and science of mixed face tunneling in the past 65 years. Although there were earlier tunnel projects in the Milwaukee area, by other agencies, the majority of those driven in the Twentieth Century have been done under contract with the Milwaukee Metropolitan Sewerage District through the agency of the Sewerage Commission of the City of Milwaukee and the Metropolitan Sewerage Commission of the County of Milwaukee. Legal Description of District The Milwaukee Metropolitan Sewerage District was created by the Wisconsin Legislature in 1921 together with the Metropolitan Sewerage Commission of the County of Milwaukee. This concept of subregional wastewater control was an outgrowth of an investigation and report from a commission appointed by the Common Council of the City of Milwaukee in 1909 to study final sewage disposal for the City. In 1911 that Commission, comprised of J. W. Alvord, George C. Whipple and Harrison P. Eddy, recommended that the City construct a water filtration plant, construct a Menomonee River flushing works, expand the intercepting sewer system and, after a thorough study of the then existing and developing methods of sewage treatment, construct a sewage treatment plant. In response to those recommendations, the Wisconsin Legislature, in Chapter 608 of the Laws of 1913, created the Sewerage Commission of the City of Milwaukee. Recognizing that the improvement of surface water quality would require action on a watershed basis, the Legislature, in Chapters 554 and 590. of the Laws of 1921, created the

Jan 1, 1979

Throughout the 1970s, the US Bureau of Mines rode an ebb tide in Washington political circles. In rapid fire succession, the agency lost its mine health and safety enforcement responsibility (1973), a large portion of its energy research responsibility (1975), and then its fuel statistics functions plus a sizable portion of its coal R&D (1977). By 1978, johnny-come-latelies in the Energy, Labor, and Interior Departments had siphoned away from the Bureau some $125 million in program responsibilities as well as 900 of its employees. The bruising decade came to a close with a Department of Natural Resources proposal that, in its original form, would have scattered the Bureau’s responsibilities to the winds. There is no doubt in my wind,” said Lindsay Norman, acting director of the Bureau of Mines (see box), “that were the Bureau to continue down the path it was on, the next step was closing the doors and going out of business.” The doors are still open, but erosion of responsibilities had a devastating effect on the resources available to fulfill the Bureau’s mission. Devastating,too, in terms of internal morale, considering the Bureau had six directors in a 10-year span. “When the troops are in the trenches and are being shot at,” Norman said, “they need a leader—hopefully, a permanent one— that can get them advancing. This is something the Bureau did not consistently have in the 1970s.” In September 1978, Roger Markle climbed aboard as director of the Bureau to rejuvenate the 70-year-old agency. He resigned only six months later* but the program Markle set in motion is being carried through by Lindsay Norman. Since Norman’s appointment as acting director, he has spent considerable time on the road explaining his agency’s redefined goals. At one such stop in Duluth, Norman and his two deputy directors, Charles Kenahan and Mike Kaas, answered the following questions.

Jan 6, 1980

By Heinz Kettling

Labor costs, which have rapidly increased in the industrial countries for several years, have forced the mining industry to develop new methods and cost saving systems. Also, because mining is basic to meeting the increasing requirements for raw materials, the mining industry is guaranteed a key position in cost cutting efforts. Although this report aims to describe major recent developments in the Federal Republic of Germany, it is restricted to a limited number of them in view of the wide variety of current innovations. The most important mining activities in West Germany are concentrated in the coal mines on the Rhine, Ruhr and Saar, in the lignite open-cast mines west of Cologne and in the potash and salt mining region in Lower Saxony and Hesse. This report will only discuss developments in the underground coal mines and the potash and salt mines, and focuses on projects of Salzgitter Maschinen and Anlagen AG (SMAG). HYDRAULIC DRILLS Drilling strata of varying strength One special difficulty faced in European coal mines is the varying of compressive strength of strata that occurs even over a few meters. The strata associated with the coal measures ranges from hard and tough sandstone or conglomerate to very soft carboniferous shale. It is often difficult to use continuous miners or roadheaders so that drifting by blasting still predominates. But the varying compressive strengths of the strata makes it difficult to choose the best method to drill the rock. For example, it is best to penetrate hard sandstone or conglomerate with heavy percussion drills. The soft carboniferous shale on the other hand, should be penetrated by high speed rotary drilling to obtain optimum performance.

Jan 1, 1979

By Ian McFeat-Smith, Robert J. Fowell

Roadheader machines have a specific place in modern tunnelling, not simply as a compromise between drill and blast techniques and full face machines, but as an economic and versatile form of mechanised tunnelling where the method of excavation is easily integrated with tunnelling operations. In the past, roadheaders have been subjected to misuses by engineers who failed to realise that, as in all mechanised tunnelling, a planned and systematic approach is essential if the full potential of these machines is to be gained. An increasing awareness of this, together with the introduction of the more powerful roadheader carrying their cutting potential into the hard range of rock is changing this situation and now makes the prospect of using roadheaders particularly attractive (1). The advantages gained by employing these machines can be considerable and Table 1 lists some of them. This table illustrates that from both cost, and installation points of view, the roadheader has considerable benefits over the full face machine. However, the principal advantage gained is in broken ground where heavy supports can be installed immediately at the tunnel face. In addition, access for planned maintenance and repairs to most working parts of the machine is at a premium and average machine utilisations of 40 - 60% can be expected. In comparison to drill and blast methods, up to 40% better progress can be regularly achieved, and the subsequent savings in overbreak costs alone would more than pay for the cost of a roadheader used to drive a 3km long tunnel. As with full face machines, ground disturbance is minimal and for short tunnels in urban areas a road-

Jan 1, 1979