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By Francois E. Heuze

We demonstrate a new capability to analyze the behavior of circular shafts in jointed rock. This was made possible by the development of a new, axisymmetric, joint finite element (2). Whereas the only previously reported such element was singular (1) and inadequate at some orientations, the current element has been extensively validated (3). The need for including discontinuities in a shaft analysis comes from two sources. First, the various rock formations may have discrete jointing, bed- ding, and interface between them. Second, there is a joint at the boundary between a concrete liner and the rock, and possibly between the various segments of the concrete liner. To demonstrate the applicability of the new model, we analyze a vertical circular shaft 5.4 m in diameter, in a series of horizontally bedded sandstones and siltstones. The shaft excavation is followed through three initial steps: 6 m, 15 m and 24 m deep.

Jan 1, 1979

By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

Hydrodynamic investigations in exploratory boreholes and grouting holes are conducted for the purpose of obtain¬ing information about the hydraulic properties of the hydrostratigraphic section to be intersected by the proposed underground workings. The information obtained from the investigations provides the basis for calculating the hydrau¬lic coefficients of fractured permeable rock, the dimensions of the anticipated grout isolation curtain(s) around the un¬derground workings, the number and location of grouting holes, the injection pressure modes, and also the volume(s) of grout that will be required (Anon., 1976, 1978). The following data on each aquifer are obtained from the investigations conducted in monitoring and grouting bore¬holes and the analysis of the results: 1) the top of each hydrostratigraphic unit, 2) the thickness of each unit, 3) the ground water fluid potential distribution in each unit, 4) the coefficient of permeability, 5) the piezoconductivity, 6) the fracture porosity, 7) the geometry of the fractures in the rock, 8) the elasticity-compressibility coefficient of the fractured rock, 9) the chemical composition of the ground water, 10) the direction of flow of the ground water, and 11) the expected inflow rate of water into the shaft, drift or tunnel. STG uses its DAU-3M type flowmeter to conduct in¬vestigations of directions of flow in vertical, inclined and horizontal drillholes. The DAU-6 instrument is used to de¬termine the direction of flow of ground water in each frac¬ture or fractured aquifer. Various singular and double DAU type packers are used for pumping and for injection studies (tests) and for flowmeter investigations. Normally the instruments enumerated above permit in¬vestigations to be conducted in each separate aquifer with¬out reinforcing the holes with casings. On the basis of these investigative data, both the hydraulic properties of unfractured rock and the hydraulic properties of the fractured rock are estimated. Dual porosity rocks require special attention because they tend to segregate the grout. 3.1 FLOWMETER INVESTIGATIONS IN BOREHOLES The STG flowmetric methodology is based on the mea¬surement of the ground water flow rate through the borehole by hydrostratigraphic interval after the disturbance of the hydrostatic equilibrium in the "hole-aquifer system" (after pumping or injecting). The relationship of the head changes to the discharge into or from a particular hydrostratigraphic unit obtained during the tests serve as the basis for calcu¬lating the hydraulic properties. Flowmetric investigations facilitate the determination of the number of aquifers, their depths, their thickness, the hydraulic properties of the fractured rock and the magnitude and direction of the flow of ground water. 3.1.1 FLOWMETER HARDWARE STG conducts flowmetric investigations in boreholes using its DAU-3M-108, DAU-3M-73, DAU-3M-57 and DAU-3M-44 instruments.' They have respective external diameters of 108, 73, 57 and 44 mm. The type of flowmeter selected for use depends on the borehole geometry and the technological scheme for carrying out the investigations. Boreholes with a drilling diameter of 76-93 mm are inves¬tigated with the DAU-3M-73 flowmeter; boreholes drilled by bits with a diameter of 112 mm and more are investi¬gated using the DAU-3M-108 flowmeter. The DAU-3M¬108 and DAU-3M-57 instruments are used for flowmetric investigations with a packer. 3.1.1.1 The Downhole Sensor The sensor design of the DAU-3M-73 hole flowmeter is shown in Fig. 2. The design of the DAU-3M-108 instru¬ment is similar to the design of the DAU-3M-73 instrument. The frame of the flowmeter sensor shown in Fig. 2 consists of a casing, an upper and lower centering mount and two rings to which the guiding rods are attached. The upper rods are built into the connector bushing; the lower rods are built into the coupling sleeve. The borehole cable is attached using a half-coupling, a packing ring and a constriction nut. Thus, the frame of the flowmeter sensor is made so that the free passage of water to the impeller is facilitated along with the necessary rigidity. The primary moving component of the flowmeter is the double-bladed impeller, which rotates on cobalt-tungsten pivots and agate thrust bearings. Special extended air cham¬bers protect the supports of the impeller from the action of the borehole fluid which may contain fibrous and abrasive particles. The air located in the chambers shields the sup¬ports from direct contact with the borehole fluid when the sensor operates in a borehole. The hollow casing of the impeller serves the function of a lower cap. The upper cap is attached to the casing using a threaded connector; it is affixed also with a lock-nut. An adjusting screw with a

Jan 1, 1993

By QINGXIANG CAI, Lin Li, PENG LIU, IZHAR MITHAL JISKANI, XIANG LU, Wei Zhou, YONGLI ZHOU

Green mining is the latest technological advancement to reduce mining’s environmental impact with minimal energy and resource consumption. Green mining — aimed at protecting nature and providing socio-economic benefits — is a multifaceted network of its connotations and key indicators. China has not yet defined its connotation and formed an effective evaluation system for surface mining. We defined its connotation and developed an evaluation index system based on the theory of green grades. As the indicators are selected based on extensive research, they express the advantages and disadvantages of various aspects of a mine. The index is composed of three attributes (safety, efficiency and environment), nine criteria and 35 indicators. The indicators were quantified according to experts’ opinions using the fuzzy comprehensive evaluation method. The results of a case study show that the environment is the most critical aspect, followed by efficiency and safety. This study can provide technical support for the development of green mining.

By I. Andras

The paper deals with the application of artificial intelligence methods in assessing the effectiveness of longwall shield support. A fuzzy sets based method is used to derive response surfaces/curves representing the dependence between basic parameters of the shield, as the initial setting pressure and the stiffness on the response metric, i.e. the convergence and load increase during a working cycle.

Jan 1, 2008

By Herbert E. Allen, Andrew F. Kingery, Spyros P. Pavlou

This paper examines and compares the role that chemical speciation plays in the environmental aquatic toxicity of two metals - copper and arsenic. Copper is shown to have well-understood chemical speciation equilibria, but poorly known species toxicities. Arsenic presents the opposite case, with unpredictable speciation in aquatic systems, but is relatively easy to evaluate toxicologically. Speciation is not currently incorporated into Water Quality Standards. This can have a major impact on the cost of environmental containment and cleanup.

Jan 1, 1992

By M. J. Shulman

The exploration geologist is frequently confronted with the problem of allocating his resources, i.e., exploration effort, among various areas. Although geologic, financial, and logistic considerations influence the allocations, no objective criterion is usually given that determines the optimal allocation. Maximizing the expected gain in information, subject to the constraint of a limited exploration budget, is used as the objective criterion to allocate airborne reconnaissance effort. The information function, I(x), quantifies the expected gain in information, where x is the scale of exploration. To calculate the information function, the following probabilities are required: the probability that an area contains a deposit; the probability that an anomaly is produced by the target; and the probability that an anomaly is produced by a barren area (false signal). Alternatively, the barren areas can be replaced by other targets. To illustrate the allocation method, the optimal number of line kilometers, i.e., the optimal line spacing per area, is determined for an aeromagnetic survey for iron in Egypt.

Jan 1, 1987

By Michel L. Van Sint Jan, Gabriel Fernandez-Delgado, Edward J. Cording, James W. Mahar

INTRODUCTION Shotcrete behavior observed in subway tunnel construction in the U. S. has been primarily in blocky or blocky and seamy rock in which rock loads develop from the self weight of individual rock blocks that tend to loosen from the wall and roof of the opening. Such conditions can be classed as loosening ground, in contrast to squeezing ground in which high pressures are generated on the tunnel lining with time as the ground creeps under the natural ground stresses. In the philosophy often associated with the New Austrian Tunneling method, emphasis is placed on the use of shotcrete and other support elements in squeezing, highly stressed ground, in which the support system is designed to allow controlled movements so that high lining stresses do not develop. In contrast to these conditions, the concern in loosening ground is to provide support soon enough to minimize loosen-

Jan 1, 1979

By G. Wayne Clough

During shallow tunneling in an urban environment, deposits or pockets of saturated soil or fractured, weathered rock are often encountered. Under such conditions, special problems with tunnel support, underpinning of structures adjacent to the tunneling, and/or flow of groundwater into the tunnel occur. If the ground conditions are appropriate, i.e., the soil is sandy, silty or fissured, or the rock is weathered or fractured, the solution to these tunneling problems may be chemical stabilization of the ground. Injection stabilization as an aid to tunneling is practiced extensively in Europe and its use is increasing in the U.S. The advantages of this technique over conventional solutions can be substantial in terms of cost and time, especially in mechanized tunnel boring where even a small zone of soft ground can bring the tunneling to a complete halt. In this paper European practice in using chemical ground stabilization for urban tunneling will be reviewed. In contrast to previous papers which have dealt with specific applications (1,5,8,9) this paper will broadly cover the subject, addressing itself to grouting techniques, costs, the reasons for grouting, philosophy of the users towards grouting, design of grouting solutions (or lack thereof) and methods of quality control. Differences with U.S. grouting practice are also noted. The information presented is derived from several visits to Europe, discussions with European and U.S. grouting personnel, and the available literature (2). The author's most recent European trip was made under the auspices of the U.S. Department of Transportation in conjunction with a research study being performed at Stanford University; a detailed report of this visit is available in reference (6).

Jan 1, 1976

By Henry N. McCarl

In the period 1982-1992, world trade has increased in real terms about 65% (Anon., 1992b). The nominal value of this trade in the early 1990s is approximately $5 trillion. In 1970, mineral commodities constituted approximately 20% of the value of world trade. By 1980, despite rising petroleum prices, mineral commodities made up about 18% of the total value of world trade, with crude oil amounting to 16% and other minerals the remaining 2%. By 1987, the major worldwide economic slowdown and falling oil prices meant that minerals constituted only about 10% of the total value of world trade, or about $500 billion in 1987 (Kimbell and Zajac, 1988). The importance of minerals in world trade since 1987 has remained at about these levels. Approximately 40% of world mineral commodity production is traded internationally. Some economists predict that minerals and other commodities are likely to continue to decline in relative importance in terms of the value of world economic output, as well as world trade, into the foreseeable future (Thurow, 1992). This projected decline in commodity demand may also be related to much slower global economic growth over the next decade (Alperovitz, 1992). Industrial minerals and rocks constituted roughly 2.5% of total mineral commodity exports in the late 1980s, but their relative importance as a portion of mineral commodity exports nearly doubled in the decade 1977-1987 (Kimbell and Zajac, 1988). Industrial minerals constitute the most rapidly growing share of total mineral commodity exports. In addition, price declines among industrial minerals were uncommon in the decade 1977-1987 (Kimbell and Zajac, 1988). While prices of sulfur and most of the fertilizer minerals have seen some erosion and slow growth in markets in the period 1987-1992, other industrial minerals have increased in both value and share of the export market (USBM, 1992). The place of industrial minerals in world trade becomes even more significant when one looks at shipments of chemical fertilizers and basic chemicals that are counted as manufactured products rather than industrial mineral commodities. The United States is the major world producer of industrial mineral commodities and products made from these nonmetallic minerals and rocks. The former Soviet Union, now The Commonwealth of Independent States (CIS), and China have very significant deposits of industrial minerals. Japan exports significant quantities of cement. The US, CIS, and Morocco export large amounts of phosphate rock. Canada and Germany export substantial amounts of potash. Sulfur from Poland, industrial diamonds from South Africa, Zaire, and Brazil, and fluorspar from Mexico are all important exports.

Jan 1, 1994

By R. D. Hamilton, W. J. Miles

In 1987, the International Agency for Research on Cancer designated crystalline silica as a 2A probable carcinogen. As a result, crystalline silica is regulated under the Hazard Communication Standard as a probable carcinogen at a concentration of 0.1% or greater in the workplace. Crystalline silica will be listed as "reasonably anticipated to be a carcinogen" by the National Toxicological Program. This designation of crystalline silica as a probable carcinogen has created major issues for the mineral and chemical producer, including labeling, hazard communications, marketing a material with potential hazard exposure, and potential liability. The State of California also regulates crystalline silica under Proposition 65 in products as a carcinogen, based upon the IARC determination that it is a probable carcinogen. More federal and state regulations are anticipated as a result of the IARC classification of crystalline silica and its subsequent federal regulation. Respirable crystalline silica has been regulated as a hazardous dust for many years by OSHA. This regulation was initiated to prevent silicosis, another occupational disease. OSHA has established monitoring devices for determining the concentration of airborne respirable silica in order to measure exposure to this substance. The accurate determination of the crystalline silica content is critical to dealing with these health risks and regulations. In the past, crystalline silica was considered to be safe and, because of its ubiquitous nature, little effort was made to determine or quantify its presence in most materials. The Hazard Communication Standard requires that a1l products containing 0.1% or greater crystalline silica must be properly labeled for this material and its hazard. Unfortunately, the 0.1% threshold was not chosen on the basis of established analytical capabilities for crystalline silica, but results from general limits for potentially carcinogenic chemicals and substances. Numerous methods have been developed for the determination of crystalline silica in a variety of products. However, these methods are not generally applicable since they must be specific for silica in any of its crystalline states and not just for total silica content. Chemical tests for silica are not difficult and quite accurate at the 0.1% level; however, in addition to its crystalline phases, it occurs in amorphous phases and in a wide variety of crystalline and amorphous silicates. In general, there is little correlation between total silica content and crystalline silica.

Jan 1, 1991

By E. B. Johnson, G. Kjerbol, L. J. Holloway

The Mount Baker Ridge Tunnel is a major improvement of Interstate Route 90 in the State of Washington. The total length of planned underground construction is about 3,400 feet (1,040 m) of which 1,332 feet (406 m) will be constructed by a stacked-drift tunneling method. Sized for vehicular traffic on two levels, the net interior diameter will be 63 feet (19.2 m) requiring an exterior diameter of about 80 feet (24.4 m). The material to be excavated is predominantly stiff clay, and this will be the largest-diameter tunnel ever attempted in soft ground. A construction contract for the stacked-drift tunnel was awarded in late 1982.

Jan 1, 1983

By Michael S. Moats, John Bailey Fletcher

The performance of grinding media can be misrepresented in marked ball wear tests due to galvanic interactions between dissimilar media. The possible galvanic interaction of media materials during marked ball wear tests has not been adequately explored. Corrosion rates and potentials of modern high carbon steel and high chromium white iron grinding media materials were measured using electrochemical testing as a function of pH and chloride content in a simulated mill water. The results replicate previous research with the high chromium white iron sample being more noble (higher corrosion potential) and corrosion resistant (small corrosion current) than high carbon steel. Using the experimental data and corrosion theory, the effects of galvanic coupling on corrosion rates were calculated to examine what could happen during a marked ball wear test or when a mixed media charge is present. This analysis indicates that high carbon steel can cathodically protect high chromium white iron leading to significant decreases in the corrosion rate (up to 99%) of this material during marked ball wear tests. The magnitude of the protection is a function of the pH of the mill water.

Dec 21, 2022

By Michael Robert Hodson

I. Introduction The free market cash price of aluminium in the third quarter of 1985 is approximately $1000/tonne, well below the short as well as the long run marginal costs of production. The current disparity between marginal costs and price, as well as the pattern of prices since their high level in 1980, has led many economists to question whether prices are governed by the 'fundamentals'. Prices, some would argue, are the result of speculation; and speculation is irrational, little influenced by the fundamentals of the industry. The object of this paper is first to examine the relation between the fundamentals and price. A number of simple models are formulated and some empirical evidence is given to show that prices are not very different from costs. There are good reasons why costs and prices have fallen since 1980. Second, the connection is drawn between the fundamentals and speculation. To do this the concept of 'rational expectations' is defined and applied to a model of the aluminium industry. Then speculation is introduced into the model and the characteristics of the solution are examined. The object is to discover the new factors that determine prices and the basic change in the nature of the solution that is caused by speculation. 2. Prices and the Simple Supply-Demand Model Consider a simple model of the aluminium industry. Demand, D, is determined by economic activity, A, given exogenously, and inversely by the price, P. Supply, Q, is determined by the inverse of the rnarginal cost curve, and so varies inversely with exogenous factor costs, C, and directly with price. Price is determined by the equality of supply and demand. Given the equilibrium level of demand, price in this model is equal to the rnarginal cost of producing the required level of demand, P = MC (Dl. Algebraically, [ ] How well does this simple model explain the change in prices during the last five years? Table I shows the LME cash price and the estimated marginal cost of producing consumption during the second quarters of 1980 through 1985. The figures in the table show that price and the marginal cost of supplying demand both fell between 1980 and 1982, rose in 1983 and by 1985 had fallen again. Only in 1984 is the direction of change different. And during the 1980 to 1985 period, marginal costs fell by approximately $560/tonne while the LME cash price fell by $678/tonne. There is a correspondence between the fundamentals of cost and price over most of the individual years and the period as a whole.

Jan 1, 1986

By R. V. Ramani

In a 1985 seminar, we were told that overoptimism abounds in Artificial Intelligence (AI), that A1 is neither a science nor a technology yet, and that we will be both exhilarated and disappointed with AI. In fact, even today, there is no single accepted definition of AI; however, certain features have been identified by AI researchers as essential to consider an entity.(e.g: machine or program) to be intelligent. According to Shank (1987), these features include communication (to be able to communicate with), internal knowledge (knowledge about itself), world knowledge (awareness and knowledge about the world outside), intentionality (knowing what one wants and a plan to seek it, ie. goal seeking behavior), and creativity (being adaptable to changing conditions). None of these figures would individually define intelligence; however, each would be a part of intelligence in its own way. The prospects for the development of entities with AI have never been as good as they are now. The combination of advancements in computer hardware and software along with new insights into the ways in which we store knowledge and use it for problem solving has enhanced the potential for the creation of intelligent entities. After some unbounded optimism of a major breakthrough in the fifties and frustrating disappointments in the two following decades, it appears now that AI has emerged from research labs to industrial practice. This is confined by the growing number of repeat applications of AI in business and industry to the extent that AI can now be considered a technology.

Jan 1, 1989

By Naoko Shimazaki, Andre Xavier

Over 10 million tourists have visited Vietnam in 2016. Travel and tourism accounted for 9.3% of the country’s Gross Domestic Product (GDP) in 2014. At the same time, as with many other resource-rich developing countries, Vietnam has been developing its extractive resources sector as a means of promoting the country’s social and economic development. In 2015, mining was the third largest contributor to GDP, and accounted for 8% of Vietnam’s gross domestic product. Vietnam is the third largest mineral producer in SE Asia. Although it produces zinc, nickel, bauxite, and manganese, coal mining is its most developed sector. The country has over two hundred coal mines, and total reserves of approximately 6 billion tons. Quang Nihn Province, where the World Heritage Site Ha Long Bay is located, is a very important tourism destination. It is also a coal-rich region where mining extraction and processing have been active since the early 20th century. Vietnam is signatory of the United Nations Sustainable Development Goals (SDGs). The country is aware of the importance and the challenges involved in managing the extractive sector in a way that does not undermine its tourism industry and yet that contributes to the country’s sustainable development. To this end Vietnam is taking actions towards implementing more advanced coal-mining extraction and processing techniques. The country is furthermore promoting a responsible mining sector, and is investing in programs that foster environmental protection and sustainable tourism. This paper examines the case of the Ha Long Bay region and the project involved in relocating the Hong Gai coal preparatory factory from a seafront area to a mountainside area. This paper provides a preliminary review of the initiatives adopted by the government of Vietnam to address the existing challenges that have resulted from a focus on promoting the country’s socio-economic development through the exploration of its rich coal endowment. Furthermore, it also describes Vietnam’s legal and policy frameworks. In conclusion this study identified that Vietnam has drafted a National Action Plan to implement the Sustainable Development Goals. The country is also taking an integrated approach to implementing the SDGs agenda and that it is assigning responsibility to a variety of ministries to achieve SDGs’ specific targets. Furthermore the country is changing policies and the legal framework in order to facilitating the execution of the work of agencies that are responsible for implementation, regulation and enforcement. In this respect, the approval of the National Action Plan on Sustainable Development Goals is another important step in that direction. While the decision of supplying its internal market with high quality coal helps minimize negative environmental impacts in Vietnam, exporting low quality coal to other countries does not help resolve the problem of CO2 emissions globally. With respect to the 2030 Agenda, this may be considered a temporary solution since to achieve the SDG goals, Vietnam will have to consider other sources of cleaner energy in order to align with the Sustainable Development Goals # 7 on affordable and clean energy.

Jan 1, 2017

By Dennis J. Lachel, Lloyd B. Underwood

In recent years a great number of papers have been presented at symposiums and have appeared in the literature relative to geologic prediction for rapid excavation and tunneling. Many of these papers describe research projects now underway to investigate tunnel site selection by remote sensing techniques, seismic holography, electro¬magnetic pulse sounding, optical scanning for structural features, and many other exotic geophysical techniques. While it is possible that this research will produce techniques that may prove to be very useful, it appears for the present at least, and perhaps for another decade, that there still will be no substitute for conventional exploration methods such as coring boring, geologic mapping, studies of existing wells, and proven geophysical techniques. Nevertheless, there is still room for tremendous improvement in the conventional techniques for geologic prediction in tunneling. These include: more rapid and accurately aligned coring borings drilled parallel to the tunnel alignment; improved geophysical surveys both prior and during construction; improved methods for predicting ground¬water inflows and water pressures, both of which can greatly influence the cost of driving tunnels. Geophysical techniques can also be ap¬plied to locate deeply incised glacial troughs or ancient buried stream channels that might cross the tunnel alignment. In the meantime, while some researchers continue their efforts to¬ward a breakthrough in new techniques for geologic prediction, it is recommended that other researchers direct their efforts toward sol¬ving specific problems such as accurately predicting ground-water conditions, determining locations of high geostatic stresses, and locations of major fault and shear zones.

Jan 1, 1997

By Peter F. Mataich

The phosphate mining industry is a highly competitive one, one in which survival depends on the plant's ability to produce at costs equal to, or below, the competition. The solution toward getting costs down is usually one of scaling up the plants to get the most tons through at the lowest possible cost. Control of these plants has been an art. Few of them are well instrumented because until a few years ago reliable instrumentation was non-existent. International Minerals and Chemical Corporation was a pioneer in applying computer techniques to ore reserves analysis and mine planning and the success in these areas led to the question of whether we could not extend the advantages of computer processing into the plant itself. There was a great deal of doubt on the operator's end that this could be done successfully because of the lack of instrumentation and the fact that plant control was largely an art that was learned only after many years of experience. However, in 1965 the instrumentation picture began to look up and the new generation of process computers just coming on the market were considerably lower in cost than the previous ones. A preliminary study of the installation costs and the probable benefits that could be realized from computer control convinced us that a process control computer should be seriously considered for a new phosphate mining plant which was being designed.

Jan 1, 1969

By Charles D. Litton

Introduction The successful performance of a mine-wide fire detection system depends upon its ability to detect the presence of a fire rapidly and reliably. It should be sufficiently rapid so that there remains enough time to either safely evacuate a mine or successfully extinguish and control the fire or both. It should be reliable so that false alarms are minimized without sacrificing sensitivity or time response. Systems should also be durable enough to withstand the mine environment over long periods of time while maintaining a high degree of re1iability. Maintenance and calibration of the system should be simp1 e and not require the expenditure of excessive time and manpower to keep it operational. Sensitivity, reliability, and durability of mine fire sensors and their electronic support systems have been the subject of significant Bureau research within recent years. The bulk of this type of information, along with the reports from which the remainder of this paper is derived, can be found in the Bibliography. It suffices to say that there exist commercially available systems for use in mines. This paper addresses a strategy for the use of such sensors and systems. Many factors influence the design of a mine-wide fire detection system, such as the potential sources and modes of ignition, the types of combustibles involved and the quantities avai1able for fire growth and flame spread. Mine air ventilation influences the growth and spread of a fire and also serves to transport the products-of-combustion to other areas of a mine remote from the fire. Fire sensor alarm thresholds place limits on the sizes of fires that can be detected. The time to respond to a detected fire, either in terms of evacuation or control and extinguishment, place additional time constraints on the design of fire detection systems. These factors interact with each other, often in complex ways, and it is the definition and understanding of these factors and their interactions that hold the key to the design of adequate and re1iable fire detection systems. Our level of understanding of the problem has increased dramatically within recent years and it is the intent of this paper to discuss the progress that has been made and how the information can best be used to improve the level of fire detection in underground mines.

Jan 1, 1986

By G. Robert Ganis

The folded Appalachians are a physiographic province of eastern North America extending from Nova Scotia to Alabama. The province strikes through the state of Pennsylvania (see Fig. 1) comprising roughly 20 percent of the state and it is here that the focus of this paper will attend. The province is a thick sedimentary sequence which was compressed into a folded mountain belt by the Appalachian Orogeny which terminated at the end of the Permian. The stratigraphy contains both carbonate and non-carbonate rocks as a reflection of the depositional environment at any specific time and place during the Paleozoic geosynclinal accumulation. Although a great deal of variety and difference exists in the geology from one end to another, a common thread of structural and stratigraphic style exists. Carbonate rocks, limestones and dolomites, comprise a substantial percentage of the total Appalachian stratigraphy and are interbedded with clastic materials such as sandstones, siltstones, and shales. The carbonate rocks are extensively mined and collectively represent a vast economic resource.

Jan 1, 1983

By H. M. Woodrooffe

In the U.S.S.R. three of the world's major-known phosphate deposits are located. These have an estimated reserve of 2,600 million short tons of contained phosphorus. The best known lies in the "Khibiny Massif', an alkalaic rock formation some 600 square miles in area with mountain peaks rising to an altitude of 3300 ft above the surrounding terrain. Location and Climate The Khibiny Massif lies north of the Arctic Circle in the Kola Penin-sula, 100 miles south southeast of Murmansk, at a latitude of 67° 30' north and a longitude of 35° 30' east. It is serviced by rail from Murmansk and Leningrad (900 rail miles south). Figure 1. The phosphate operations are centered about the two cities of Apatity and Kirovsk. The former has a population of 35,000 and is on the Leningrad¬Murmansk railway. Kirovsk, 15 miles to the east, is now a city of 85,000. The region is at the limit of the tree line with most of the ground cover typical tundra. The mean annual temperature is -4°C and, in a normal year, precipitation occurs on 240 days. Because the temperature does not exceed freezing for 300 days each year, virtually all of the precipitation is snow. The two towns are nestled between mountains and, because of the weather, extensive avalanche control systems incorporating major engineering construction have been introduced to divert snow slides away from the populated areas. General Kirovsk was first settled in 1923 and the apatite occurrences were recognized shortly after. In 1933, the first concentrator for the recovery of the mineral was completed, producing in its first year of operation 170,000 tons of concentrate. With the growth and demand for phosphate in the U.S.S.R., a second concentrator was erected at Apatity. It calve on stream in 1963. Because of the severe climate, in the early days mining was limited to 85 days per year. With the introduction of new techniques and improved mining methods, the season has been extended to 115 days.

Jan 1, 1972