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By Malcolm J. McPherson

This paper describes the algorithm used in a BASIC program for an IBMXT microcomputer, to simulate the underground mine climate. The program called CLIMSIM has been developed and refined over several years as a result of considerable use at operating mines. The program has been designed to be easy to use and be understood by the practicing mine ventilation engineer. It provides predictions of the work place climate, so that the optimum ventilation/cooling system can be designed to obtain a certain air cooling power or effective temperature at the work place. An example is given of the application of the program to a mechanized cut and fill stope at the Homestake gold mine in South Dakota.

Jan 1, 1986

By K. R. Gardner, P. B. Altringer, R. H. Lien

The Bureau of Mines, U. S. Department of the Interior, is investigating biological and chemical reduction of selenate and selenite from waste waters. A mixed bacterial culture, isolated from agricultural waters, removed selenium from four oxidized cyanide solutions from precious metals operations containing 0.6 to 30 ppm Se and 13 ppm CN. Up to 85% selenium removal was attained using bacteria under controlled batch conditions in a 3-L stirred tank reactor and in small-scale continuous tests conducted in a rotating biological contactor (RBC). Fe(OH), reduction of the selenium reduced the effluent concentration to 0.02 ppm Se; however, the reagent costs were prohibitive. A final processing scheme may involve a combination of biological and chemical treatments.

Jan 1, 1991

By Robert S. Mayo

The haulage of muck from mines was first illustrated by Georg Agricola in De Re Metallica in the year 1556. In many of his ancient wood cuts he showed a crude car running on wooden rails. These wheels had no flanges. There were four pins sticking down from the car to guide it along the rails. Eventually they made the wheels of cast iron with flanges on them. In England, coal was hauled from the pit mouth to the nearest river or canal in "wains", or wagons, running on the common highways. These wains carried one chaldron of coal, weighing 2500 lbs and it took six horses to haul these wains over the atrocious roads of that day. Somebody, about 1760, invented a cast iron rail. These were cast iron troughs, 4 ft long laid on wooden sleepers. With these iron rails they found that one horse could do the work of six. But this U-shaped groove trapped all the dirt and grit. Somebody had the brilliant idea of attaching a flange to the inside of the wheel and from then on the rails were of timber protected against wear by a strap of iron. Rolled rails, of wrought iron, were first used in England in 1820. I am sure that many of you people have wondered why the British and American railroads standardized

Jan 1, 1974

In a world dependent in part on the consumption of depletable natural resources, development of new areas of mineralization is a necessity for replacing those reserves. Exploration, which is the initial task of replacement, is an information-gathering process which supplies input for management decisions on mine development. If the demand for resources is the driving force of exploration, then the scientific basis for its pursuance is the hypothesis of anomalous mineralization in a metallogenic province, which is tested by measuring physical characteristics of natural phenomenon. The resulting data are reduced, analyzed, and interpreted to locate expressions or responses associated with possible ore bodies. The process is, in fact, repeated in ever increasing measurement detail to increase the accuracy and precision of information for decision making. Exploration ceases when management makes the decision to develop a mineralized area, to hold a property for more favorable market conditions, or to drop a property because it is not economically viable.

Jan 1, 1979

By Edita Vircíková, J. B. Hiskey, Ludovít Molnár, Peter Lech, B. J. Scheiner

This paper describes the results of a study of hydrometallurgical methods of producing sodium arsenate for the glass industry from arsenic oxide wastes occurring in carbon dioxide washing. This paper addresses the following aspects: theoretical assumptions for leaching arsenic and its oxides, experimental results of As(III) oxidation to As(V) in aqueous solutions, sodium arsenate crystallization (the system As2O5-Na2O-H2O), characteristics of the crystalline product, and pilot-plant tests using sodium arsenate in the glass industry.

Jan 1, 1993

By Osamu Shoji, Mamoru Kato

In order to continue improving the quality of telecommunication services to meet the expectations of the people and to increase reliability in the case of emergency such as disasters, Nippon Telegraph and Telephone Public Corporation (NTT) is now constructing cable tunnels which connect main urban telephone offices. However, almost all the large cities in Japan are built in river deltas, so that their chief underground features are low strength fluvial deposit and a high ground water level. In this saturated soft ground, the ground surface at an installation site has occasionally subsided through deep excavations for cable tunneling construction. As these settlements have sometimes caused accidents, especially in densely populated large cities, NTT has made much effort to avoid such accidents. These accidents have occured mainly in flexible sheeting due to its inward movement. Therefore, after the investigation into forecast method of sheeting deflection with accuracy, NTT has reserched a system which forecasts ground surface settlements. This paper describes an outline of the ground settlement forecast system and practical example on the site.

Jan 1, 1979

By Bernard Lippe

The successful construction project is one in which the component construction operations are completed within the scheduled time and cost parameters. Most construction projects, however, are subject to delays and/or disruptions which adversely affect the time (start, duration, and completion) and cost aspects of the project. DELAYS Delays fall into two categories: Compensable Delays for which the contractor is entitled to contract time extensions and additional money as compensation for the extra expenses generated by the delay or obstruction to job progress, and Non Compensable Delays, for which the contractor may or may not receive an extension of time but no additional compensation. Compensable Delays Compensable delays may take the form of holds or suspensions on all or certain segments of a project by the owner, failure of the owner or his Engineers to approve shop drawings, cuts or material samples within a reasonable period of time, failure of the Owner or his Engineer to properly coordinate the job, discovery of design deficiencies in the plans and specifications which prevent the continuation of construction until

Jan 1, 1974

By D. L. Misterek, E. J. Slebir, G. W. Ring, M. A. Laird

INTRODUCTION In 1973, the Federal Highway Administration (FHWA) initiated a 10-year program of research on tunneling technology for future highways as a part of a larger Department of Transportation effort on tunnels. The objectives of the FHWA program are to: improve tunnel design technology, reduce costs, minimize adverse environmental impact due to construction, increase the rate of construction, and assure the maintenance of a safe and attractive tunnel environment. The program is divided into four research tasks designed to solve tunneling problems identified by the engineering and field offices of the FHWA. These tasks are as follows: 1. Cut-and-Cover Tunneling 2. Site Investigations 3. Ground Movements - Prediction and Control 4. Highway Environmental Criteria for Tunnels In order to provide input into Tasks 2 and 3, the FHWA is sponsoring an investigation and testing program by the U.S. Bureau of Reclamation to instrument and monitor two sites in the second bore of the Eisenhower Memorial Tunnel located on Interstate Highway 70 at Loveland Pass approximately 97 km (60 miles) west of Denver, Colorado. The tunnel will be approximately 14.0 m (46 ft) in diameter when excavated. The study is designed to generate data on: (1) changes in the state of stress, and movements during and after tunneling, (2) tunnel lining design requirements, (3) developing a

Jan 1, 1976

By Meliton M. Garcia, Satya Harpalani

This paper discusses the results of an investigation carried out in an underground mine to characterize the volatile by-products adsorbed on airborne particulates following the detonation of four common explosives including ANFO. The primary objective of this study was to determine if any organic amine compounds, particularly nitrosamines, and any polycyclic aromatic hydrocarbons were produced and trapped in the dust that a miner might inhale during the workday. The production of these substances is of great concern because of their suspected carcinogenic nature. The results of the study indicated that a large variety of the by-products are adsorbed on the particulates generated, and thus remain airborne following the detonation of explosives. The major by-products retained by the dust were bis(2-ethylhexyl) phthalate, and aliphatic hydrocarbons with carbon chains ranging from C12 to C28. One explosive, a water gel, produced the polycyclic aromatic compound, trimethylnaphthalene. No nitrosamine compounds were detected.

Jan 1, 1989

By Henry P. Ehrlinger III, Latif Khan, John M. Lytle

The primary purpose of this project was to produce and test coal concentrates made from coal preparation plant waste fines for use in a slurry-fed gasifier. Concentrates from several individual waste streams were examined to determine their amenability as feedstock for a slurry-fed, slagging, entrained-flow gasifier. The tests included analyses of the plant feed and product, material balances, and estimates of gasification reactivity and of pumpability. The following preparation plant fines were examined: • fresh rejects produced in a plant processing underground- mined Springfield Coal • fresh rejects produced in a plant processing underground- mined Herrin Coal • fresh rejects produced in a plant processing surface-mined Springfield Coal and Herrin Coal • Five-year old impounded fines rejected during processing of underground mined Herrin Coal. At high coal recoveries the Btu content of the concentrates was greater than the Btu content of the utility product from the plant. The coal recovered from fines was found to be entirely acceptable for gasification and pumping without additives.

Jan 1, 1995

By Y. Ooishi, Y. Matsumoto, T. Arai, H. Ohta

The multi-circular face shield (MFS) is a new type of tunnelling machine for construction of the special cross section and has been put to practical use in 1988. The MF shield has two circular faces partially overlapped in a single shield machine and can construct the cross section shaped like glasses for the double track railway. And it is possible to equip two or more cicular faces horizontally or vertically, if necessary. During the development of the MF shield the experiments have been carried out for the purpose of estimating the excavatability and the face stability of the MF shield. As a result it was confirmed that the both types of MF shield (one with double faces aligned horizontally and the other with double faces aligned vertically) has higher performance in the face stability and lower value in the cutter torque and the total thrust than the conventional circular shield.

Jan 1, 1991

By M. Di Tommaso

Acid Mine Drainage (AMD) is a quite diffuse environmental problem in dismissed sulphur mine districts. AMD is related to sulphur oxidation of abandoned tailings, generating heavy metal-bearing streams with high iron and sulphate contents and low pH. Treatments of AMD aim firstly to increase the pH to reduce its leaching power causing the further release and mobilization of heavy metals through soil solution and groundwaters. Increasing the pH also allows the precipitation of iron (III) (involved in sulphur oxidation and then in AMD generation) and the partial removal of other toxic components such as arsenic. pH adjustment and the reduction of the high concentration of iron are also necessary for the successive biological treatment in permeable reactive barriers (PRB) with sulphate reducing bacteria (SRB) (II step, biologically mediated precipitaton/biosorption) to avoid the rapid plugging of the barrier (for the large amounts of iron precipitates) and to ensure neutral pH conditions for SRB growth. In this work the first step (chemical precipitation) of a combined chemical and biological treatment of AMD is presented. Experimental data from column tests using carbonate stones to remove iron and increase pH were reported. Toxicity tests have been carried out on the treated wastewaters by Lepidium sativum.

Jan 1, 2006

By M. S. Enders

The McDonald gold deposit is located in the upper Blackfoot Valley in Lewis and Clark County in west-central Montana, about 65 km (40 miles) northwest of Helena and 13 km (8 miles) east of Lincoln (Fig. 1). The McDonald project area covers about 20.7 km2 (8 sq miles) of elevated terrain on the north side of the Blackfoot Valley. The Blackfoot River lies 1 km (0.6 miles) south of the McDonald deposit. East Butte and West Butte rise 300 m (985 ft) above the Blackfoot Valley to an elevation of 1,750 m (5,740 ft). They conveniently divide the area into two parts. The Seven-Up Pete Joint Venture (SPJV) is a partnership between Phelps Dodge Mining (72.25%) and CR Montana, a subsidiary of Canyon Resources (27.75%). SPJV controls about 83 km2 (32 sq miles) of mineral and surface rights in the Lincoln area. The McDonald project is on state-owned and private land. The joint venture has conducted exploration since 1989 at the Seven-Up Pete, McDonald and Keep Cool areas (Fig. 1).

Jan 1, 1995

By J. C. Norman

The boron review did not arrive in time for publication in the June issue. The United States was the world's largest producer and consumer of boron compounds during 1992. The US Bureau of Mines estimated that boron mineral concentrate and chemical production in the United States totaled 1Mt (1.1 million st) in 1992, yielding 521 kt (574,000 st) of B203 for a total estimated value of $333 million. That was about 20% less than 1991 revised production figures, and less in value by $107 million. The United States continues to provide essentially all of its own boron supply while maintaining a strong position as a source of sodium borate products and boric acid to foreign markets. Domestic employment in the mining and beneficiation of boron products in 1992 was about 900 people, the same as in 1991. In 1988, 1250 people worked in the boron industry. The Bureau estimated that total world production of boron in 1992 was about 3 Mt (3.3 million st), or about 1.2 Mt (1.3 million st)of B2O3. World production in 1992 was about equal to revised 1991 levels. US production Mines and processing operations in southern California were the only domestic sources of boron mineral concentrates and chemicals. US producers, in order of quantity of production, included:

Jan 1, 1993

By Gary W. LaChapelle

Cyprus Miami Mining Corp. has a history of overcoming adversity through innovation and adaptation to changing conditions. Requirements to remain profitable in the 1990s include a combination of advanced technology, employee involvement and training, attention to customer satisfaction, environmental awareness and quality management. The Miami property is located in the Globe-Miami area of Arizona, 130 km (80 miles) east of Phoenix and 160 km (100 miles) north of Tucson. The complex is located in a high desert environ¬ment at an elevation of 1065 m (3500 ft). The region receives about 480 mm (19 in.) of precipitation annually. History Mineralization at the Miami property was first discovered in the 1880s, which led to underground mining of copper by the 1890s. In 1911, the Inspiration Consolidated Copper Co. was formed by combining the Inspiration and Live Oak Mines. Full-scale production began in 1915. Block caving methods were used at both mines. Open-pit mining commenced in 1948. Underground mining had ceased by 1954, and all production was obtained from surface operations. Innovation has been the key to Miami's success. Development of sulfide flotation and the ferric cure process for vat leaching were advanced at Miami. In situ leaching of oxide material, remaining after block caving had removed the sulfide ore, was also used.

Jan 1, 1993

By J. E. Gebhardt, D. A. Rice, P. E. Richardson

An improved understanding of the significant role of electrochemical reactions in sulfide flotation has evolved in the past 20 years, This understanding has been accompanied by a corresponding increase in attempts to control the electrochemical potential of flotation pulps for monitoring and controlling sulfide flotation circuits to improve metallurgical performance. This paper discusses the basic electrochemistry of sulfide flotation and the use of electrochemical potential as a control parameter.

Jan 1, 1993

By W. Ter-Minassian

Besides the question of the stability of the roof and walls, one of the main problems encountered with tunnelling and shaft-sinking through the soft ground of alluvial origin forming the sub-grade of most large towns is settlement. Public transport and road tunnels in town centres are particularly affected, as they cannot generally be designed at any great depth for several reasons, such as the fact that ventilation shafts and access to the surface by means of stairs, escalators, lifts, ramps and so on must be fitted into the limited space available and are therefore costly, and because of the difficulties of driving below the water table. It is for this reason, coupled with the need for wide radius curves, that tunnels now so often pass close under buildings and monuments which must not be exposed to any risk of damage from subsidence during excavation. Grouting is the usual method used for consolidating soils, improving their strength and making them less compressible, but it is itself liable to cause heaving and cracks in the buildings above and has many other attendant dangers, including continually revised estimates which are the reason for the often inordinately high costs met with in urban tunnelling to-day. The mechanics of the problem have been studied and it has been found that a fraction of the total settlement is

Jan 1, 1997

By David D. Spencer

As in many other areas of the Mexican economy, the legal rules applicable to mining in Mexico have been changing fast. Mexico's mining sector is opening up to levels of international participation that were unforeseeable just a few years ago. Over the last several years, Mexico has made dramatic changes in its trade and investment policies. Many of these changes have their roots in the administrations of Miguel de la Madrid and perhaps even Jose Lopez Portillo. However, the current administration of President Carlos Salinas must be given credit for articulating, advancing, promulgating and implementing these changes. Just a few short years ago, few people believed Mexico would repeal so many of its restrictions on foreign investment and lower its average tariff level from something around 100% to less than 10%, where it is today. NAFTA and mining The North American Free Trade Agreement (NAFTA) is the most comprehensive international expression of Mexico's new policies. Except perhaps for the agreements establishing the European Union, NAFTA is the most detailed trade agreement ever written, consisting of about 2000 pages. The provisions of NAFTA with the greatest relevance to the mining industry include the chapters on investment and government procurement. Many mining companies may also find the temporary work provisions relevant. Finally, no discussion of NAFTA and the mining industry would be complete without some mention of the North American Agreement on Environmental Cooperation, the so-called Environmental Side Agreement.

Jan 1, 1994

By Allen J. Sobczak, Peter J. Peters

The five tunnel contracts of Milwaukee Northeast Side Relief Sewer System are about 80 percent complete. The tunnels are all excavated for 1.9 meter (6'-0") finish diameter sewers in a variable rock, mixed face, and glacial soil environment. Different contracts were let under two primary types of specifications, performance and prescriptive, which treated aspects of construction, such as primary ground support and groundwater control, differently. Interfacing of design and construction through field personnel allowed the needs of all parties to be met and resulted in savings in time and money to the Milwaukee Metropolitan Sewerage District (MMSD). Interfacing, cooperation and risk sharing allowed resolution of problems such as line and grade variations and potential differing site conditions. It also allowed the parties to pursue constructive changes to construction activities. Thus on one contract prescribed use of compressed air was eliminated, but migration of fines into the tunnels was stopped with filter fabric. Use of an expensive primary support system was dropped, but concern about deterioration of lagging was alleviated by use of special materials.

Jan 1, 1983

By Hans W. Brodbeck

The Advisory Conference on Tunnelling of the OECD, held in Washington, D.C. in June 1970, has established the following definition: "Tunnelling refers to the construction by any method of a covered cavity of predesigned geometry whose final location and use are under the surface, whose cross-sectional area is greater than 2 square metres". (1) The definition makes clear that the term includes all types of underground construction, be it in hard rock, soft ground, under mixed conditions, underwater, etc. Small-sized tunnels in rock therefore constitute but one part of the tunnelling scene. With an ever-growing urbanisation taking place in industrialized as well as developing countries, the demand for small-sized tunnels is, however, rapidly increasing and requires a far-reaching mechanization of excavation and support functions. This trend is accentuated by the fact that small-sized tunnels are far more labor-intensive than large ones, and, with wages raising at a much faster rate than costs for plant and equipment, this will accelerate the introduction of new tunnelling systems. SMALL-SIZED ROCK TUNNELS The main field of application for a tunnelling system for small sized hardrock bores is thus defined. It is in fact the numerous relatively short tunnels required under cities and other populated

Jan 1, 1974