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By Terence G. McCusker, E. Roy Anderson

A four-mile length of interceptor sewer tunnel in Manhattan has finished sizes ranging from 10'6" to 14'6" horseshoe. Mixed face conditions were anticipated in three areas and encountered in five. All were short but since the tunnel lies well below the water table and failures would involve important utilities, major structures and human lives, great care had to be exercized in choosing a construc¬tion method. Chemical consolidation was selected as the best approach with compressed air working as a backup system. Initially grouting was accomplished from within the tunnel, but treatment from the surface was more successful and was later adopted. The soils consisted largely of impermeable weak silts and it was found possible to inhibit access of water to this material so that it could be controlled by breasting within the tunnel without loss of stability. It is concluded that in the interlayered permeable and impermeable soils encountered, chemical grouting would successfully stabilize the working face. INTRODUCTION An interceptor sewer is currently under construction along the entire length of the west side of Manhattan. When complete, the tunnel will intercept and divert to a treatment plant (also under construction) a daily flow in excess of 200 million gallons per day. About 9 miles of the interceptor sewer is in tunnel and the remain¬der is cut-and-cover construction. The tunnel is almost entirely in Manhattan schist but where its alignment crosses major faults at comparatively shallow depths, mixed face and earth conditions are

Jan 1, 1997

By D. A. Rice

As part of a cooperative effort between the U.S. Bureau of Mines and the Florida Institute of Phosphate Research (FIPR), with input-from the phosphate industry, the conversion of phosphor-gypsum to sulfur is being investigated. The proposed process incorporates a thermal reduction of phosphogypsum to calcium sulfide (CaS) and a hydrometallurgical treatment to convert calcium sulfide to ammonium bisulfide (NH4SH), which is then oxidized using a catalyst to produce elemental sulfur. The paper summarizes the results of continuing laboratory studies using an activated carbon catalyst which was loaded with sulfur through oxidation of ammonium bisulfide solution. The extraction of the sulfur that forms in situ on the catalyst is a key area in the development of the sulfur recovery process. Two approaches for removing the sulfur are being investigated: 1) thermal treatment to volatilize sulfur, and 2) leaching the sulfur using liquid anhydrous ammonia. The research has shown that it is technically feasible to recover over 90% of the sulfur from the carbon by either volatilization or ammonia leaching. Locked-cycle testing has demonstrated that the carbon has the potential to be recycled after ammonia leaching.

Jan 1, 1988

By Leslie S. Halasz

This paper describes the techniques implemented at Randfontein Estates to develop twin-haulages at 'high speed'. An operation which culminated in the world record advance for twin-end multiblast cyclic development in hard abrasive quartzites. A major expansion project was planned for the mine, with the sinking of a third twin-shaft system (to be known as Cooke No. 3), to raise the level of ore production from 3 500 000 to 5 000 000 tonnes per alumm. Subsequent redesign of the proposed shaft system as a single 9 m brattice wall shaft took place, reducing the planned shaft sinking period by 12 months and saving an estimated R 250 000 (U.S. $ 330 000) in sinking costs. The advancement of the Cooke No. 3 Shaft sinking and development programme necessitated a rapid excavation schedule for two interconnecting twin-haulages from the existing Cooke No. 2 twin shaft complex to provide a second means of egress. An early holing between the two shafts would provide significant financial and technical benefits. Pre-development and equipping of shaft pillar excavations would enable a rapid shaft production build up and blocking out of at least one year's ore-reserves.

Jan 1, 1983

By Charles P. Lazzara, Alex C. Smith, Mark W. Ryan

The U.S. Bureau of Mines developed an experimental method to evaluate the relative effectiveness of water additives on the extinguishment of coal fires. The experiments were conducted in the fire zone of the multiple entry section of the Bruceton Experimental Mine. Chambers filled with one hundred and eighty kilograms of Pittsburgh seam coal were ignited and allowed to burn until well developed fires were achieved. Extinguishing agent-water solutions were then applied to the fires and the quantity required to extinguish the fires compared to the amount of water alone required to extinguish similar fires. A 20% diammonium phosphate-water solution required an average of 22 L to extinguish the coal fires, while two commercially available additive-water solutions required an average of 30.6 and 30.3 L, respectively. The average amount of water required to extinguish the fires was 28 L. An analysis of covariance, using the thermal energy of the coalbed, Q, to quantify the fire at the time of extinguishment, showed that the diammonium phosphate-water solution was slightly more effective at extinguishing these coal fires than water alone, while the two commercially available additive-water solutions were statistically equivalent to water alone.

Jan 1, 1992

By J. M. Schisler

In the last five years Eldorado Resources Ltd. (ERL) has undergone a major expansion and modernization of its uranium refining and conversion plants. A new refinery for processing yellow cake to UO3 was constructed at Blind River in northern Ontario and started up in 1985. Its rated capacity is 18,000 t/a uranium as UO3. At Port Hope, Ontario, ERL's new UF6 conversion plant has been constructed. This plant started up in 1984. It utilizes the novel, wet-way process to produce UF4 and gives the company a UF6 production capacity of 14,500 t/a U. Also at Port Hope is Eldorado's ceramic UO2 powder production facility, commissioned in late 1980. It has a capacity of 1700 t/a uranium as UO8. With the completion of these capital projects, Eldorado has the largest and most up-to-date refining and conversion facilities in the western world. This paper reviews the refining process and process design. The methodology used to start up the Blind River plant is described as are some startup difficulties, solutions that were developed, and the resultant current operation.

Jan 1, 1987

By Gerhard Mücke

Geothermal and operational reasons in the German coal mining industry make it necessary to an increasing extent to climatize coal faces and headings by means of refrigeration plants. Air coolers installed on coal faces as well as in gateroads play an important part in such climatization. They must transfer, under difficult conditions, the refrigerating capacity supplied by central or de-central refrigeration plants from the chilled water to the air in the workings. The performance data of two new types of coalface coolers and of two different types of gateroad coolers were measured in two testing stations under different thermo- dynamic conditions with dust-free fresh air. As air coolers must be installed particularly at working points with a high .dust load the heat exchanging surfaces are fouled for the most part causing an essential reduction of the refrigerating capacity. The investigations therefore were extended to measurements with a certain dust load in the intake air of the coolers.

Jan 1, 1980

By R. Pandey, G. Elie, E. Sarver

Respirable crystalline silica (RCS) is generally considered the most hazardous constituent of coal mine dust, and a new federal rule is expected to further limit exposures in U.S. mines. For regulatory purposes, RCS is monitored by collecting filter samples, which are analyzed for quartz (the predominant form of RCS in coal mines). The analysis is done using Fourier transform infrared spectroscopy (FTIR) in a centralized laboratory. To enable more timely results, National Institute for Occupational Safety and Health (NIOSH) mining researchers developed a directon- filter (DOF) FTIR analysis method and free FAST software that can be used in the field. For samples collected under specific conditions, FAST processes the FTIR spectral data to determine quartz mass. While the DOF FTIR method is not approved for regulatory RCS monitoring, it could be useful for engineering purposes, such as to evaluate mining parameters or new dust controls. This field study demonstrates how the method, including FAST, can be applied using low-cost, widely available sampling components. It further demonstrates how quartz percentage can be estimated in the field, by pairing a continuous personal dust monitor with a filter sampler.

Jun 1, 2025

By Russell K. McFarland, Eugene L. Foster

INTRODUCTION The U. S. Department of Transportation has underway an important new program which will have a major impact on rapid excavation technology. The Transportation Tunneling Program, as it is called, is a coordinated, multi-modal research and development effort. Its goals, if realized, will significantly improve our ability to build the underground structures needed for transportation. This, in turn, will improve transport efficiency, environmental impact, and the energy consumption associated with the movement of people and goods. Tunneling technology research and development had its beginning at the Department of Transportation in the Office of High Speed Ground Transportation (OHSGT). The OHSGT developed and implemented a program in 1965 to provide the technology for underground construction needed to support future high speed ground transportation. In 1967, when the OHSGT was transferred from the Department of Commerce to the Federal Railroad Administration (FRA), the program accompanied that office. The thrust of the FRA program has been cost reduction through the development of new materials, innovative designs, and better construction methods. During the late 1960's and early 1970's, other developments were underway which would influence the future of tunneling research at the Department of Transportation. An ad hoc

Jan 1, 1974

By Richard J. Adams

Coal jigs have played a predominant role in U. S. coal preparation for fifty years. Recently, an improved fine coal jig has been used to prepare the middle size range coal. These efficient machines are changing the historical thinking about jigs and is consistent with trends in coal preparation throughout the world. The performance achieved and operating cost savings are causing a change in fine coal cleaning strategy. With the exception of a handful of operators, fine coal jigs are generally not well understood by the industry. The objective of this paper is to provide some insight into the past use of fine coal jigs and their potential in the future. Improved Fine Coal Jig Since the mid 701s, an improved fine coal jig has been employed to an important niche in preparation, the 19 mm x 100 M range of cleaning. Several factors due to mining and liberation considerations have caused an expansion of this middle range of coal resulting in a host of challenges for coal preparation engineers. Fine coal jigs have been commissioned in several installations in North America to handle these important applications as shown in Table No. 1.

Jan 1, 1988

By Robert W. Lawson

INTRODUCTION Prior to 1705, underground mining was limited to mineral deposits located above or a very small distance below the water table. The development of the steamdriven mining pump was motivated by the need to extract minerals from deposits considerably lower than the water table. Today, the majority of mine pumps are driven by electric motors, although some small utility pumps are driven by compressed air. Of the numerous types of pumps that might be applied to mine service, the two types used most frequently underground are the centrifugal and plunger pumps. Each of these types has its proper application. In most instances, plunger pumps are best for handling low water volumes against high heads, while centrifugal pumps effectively handle either low or high water volumes against low heads or high water volumes against high heads. This chapter describes pumps applied to underground mine service, where the mine service consists of mine drainage (removing mine water as it accumulates), mine dewatering (removing water from a flooded mine), and pumping for special applications such as hydraulic mining and hydraulic hoisting. CENTRIFUGAL AND PLUNGER PUMPS Modern mine pumps are classified as either centrifugal (kinetic) or plunger (positive-displacement) pumps. The following paragraphs describe each of these classifications. Centrifugal Pumps Centrifugal pumps may be grouped into various types, depending upon their various features: Number of Stages: In a single-stage pump, the total head is developed by one impeller, while a multi¬stage pump utilizes two or more impellers acting in one casing to develop the total head. Fig. I shows a cutaway view of a single-stage horizontal split-case double -section centrifugal pump. Fig. 2 shows a cutaway view of a six-stage medium-pressure split-case diffuser-type centrifugal pump. Type of Casing: A volute pump has a casing in the form of a spiral or volute. A circular-casing pump has a casing of constant cross section concentric with the impeller. A diffuser pump is equipped with a diffuser that converts velocity head to pressure head. Shaft Position: A horizontal pump normally has the shaft in a horizontal position, while a vertical pump normally has the shaft in a vertical position. Fig. 3 illustrates a vertical turbine-type slurry pump. Suction: A single-suction pump equips the first stage with a single-suction impeller, with fluid entering the impeller on only one side. A double-suction pump equips

Jan 1, 1982

By A. E. Hall

INTRODUCTION Underground gold mining operations are found in South Africa, U.S.S.R., Canada, the United States, Zimbabwe, Ghana , Brazil. Australia, China and many other countries. The methods used for extraction differ from highly mechanized trackless mining in the developed countries to the labour intensive systems of the third world nations. The climatic conditions in which mines are situated vary from equatorial to arctic. The rock temperatures and the depth of workings also vary significantly from shallow to extreme depth. The Western Deep Levels mine in South Africa is the deepest and exceeds 4.000 metres in depth with strata temperatures above 55°C. These major differences between mining fields result in significantly different ventilation problems in underground gold mines. The ore types also vary and some deposits have high silica contents while other mines extract sulphide ores. Methane may also be encountered in underground gold mines and can have a large influence on the ventilation practice. Several topics are currently of concern to operating mines and are reviewed here:- a) Air circulation and fans b) Mine cooling c) Permafrost operations d) Mine heating e) Control of diesel exhaust f) Gases, fires and explosions

Jan 1, 1988

By David L. Martin

This paper discusses the development of a SLAM II* simulation model with imbedded optimization modules designed M evaluate mineral exploration and exploitation strategies. The model traces through a sequential exploration program, evaluating each deposit site based upon geologic information and potential profitability of the site. At a specified time during the simulation, a new production plan is developed for currently producing deposits which takes into account the planning horizon and deposits which are currently being explored. Potential uses of the model by geologists, engineers, and management decision makers include setting corporate objectives and policies on exploration and production. The model is also useful for testing past decisions to evaluate decision making criteria and evaluating mineral deposit profit potential.

Jan 1, 1983

By H. L. Ehrlich

Processes involving biological solubilization of metal values from ores, or removal of mineral constituents that interfere with metal value recovery from ores by abiological means, published mostly in the last 10 years, are reviewed. Many of them, though promising, have yet to be tested on a pilot scale or applied industrially.

Jan 1, 1987

By S. B. Patton

A computer model, which quantitatively utilizes the relationship between the interactive and dynamic processes of methane drainage, mining, and ventilation, is presented. The model includes simulation of the coalbed methane reservoir for prediction of gas-emission rates under the influence of degasification wells and longwall mining, ventilation network-generation, and ventilation simulation. As mining progresses step-wise through the coalbed-methane reservoir, the ventilation network is created and subsequently simulated, iteratively determining fan requirements to safely reduce methane concentrations. The model can be used to quantitatively study the effectiveness of methane degasification on the ventilation system in a longwall panel.

Jan 1, 1992

By Quan Li, Xiang Ren, De Lui, Yumin Zhang

SL-type continuous centrifugal separator with injection flow (Injection Flowing Film Centrifugation, IFFC) for separating fine and ultra-fine minerals has been developed recently in China and it is capable of recovering particles down to one micron in size. In this paper, the principle of its separation is discussed. IFFC is a special transient pulsating film which combines both thin film jigging and thin film concentration functions. It not only can intensify the looseness and stratification of the settled particles, but also create a hydraulic weir effect to improve recovery of fines and ultra- fines and significantly improve the performance of thin film separation. In a Chinese tin gravity concentrator, SL devices, SL-1200s (capacity 1.5-2.0 ton/hr) and SL-600s (capacity 0.5 ton/hr) were applied to treat -1 0 micron cassiterite slime(removed as tailings at the past) and to replace the old tin flotation system(-74+10 micron slime). The plant results show that 50-60% of the cassiterite can be recovered from -10 micron slime with an enrichment ratio of 10-12. Particle down to one micron were recovered. Under optimal conditions, the recovery from -74+10 micron slime can reach more than 85%. The recoverable size range can be determined by calculation.

Jan 1, 1995

By R. D. Call

During the past fifteen years considerable progress has been made in the technology of slope design. It is possible to design rational slope angles if suitable data on geology, hydrology, and rock properties are available. It is of course preferable to conduct a full scale slope design study, but there are those situations where a full scale study is not feasible because of time and budget constraints. In this paper we will treat two situations: (1) choosing slope angles for a preliminary feasibility study at the exploration stage; and (2) dealing with a slope failure in an operating pit. In these instances slope angles must often be chosen on the basis of available or readily obtained data. In an exploration program all too often a feasibility study is initiates just a few months prior to the decision deadline to drop the property or to exercise an expensive purchase option. If all that is available at this point are a few cross sections at odd angles showing ore and waste contacts and a dog-earred map of the surface geology there may not be time to collect and organize enough information for design of slope angles. On the other hand if during the drilling program geologic cross sections are constructed and the structural data is presented in tabular form, rational slope angles can be determined within the allotted time. Certain types of data can be collected only at specific times during a project. Two prime examples are logging fracture intensity and collecting samples for rock testing before the core is split. It is particularly disheartening to ask to see the core and to be shown a tattered cardboard box filled with plastic bags of sample pulps.

Jan 1, 1976

By B. J. Scheiner

The Bureau of Mines has developed a system for dewatering waste slurries by flocculating mineral particles with polyethylene oxide (PEO) and dewatering the resulting flocs on static and/or rotary screens. This paper discusses data obtained from dewatering, rheology, and ion-exchange experiments. A possible mechanism is postulated for the attachment of PEO to claylike particles through a water bridge with the intershell waters of the exchanged ion and the polymer.

Jan 1, 1986

By E. Sabina Brady

Over the next two decades there will be significant trade and development opportunities in China for mining, engineering, equipment, and construction companies interested in becoming part of the development of China's chemical and fertilizer industries. At last count, China's phosphate ore reserves of 11.8 Gt (13 billion st), ranked fourth in the world behind the US, the USSR, and Sahara-Morocco. However, a recent statement by the head of the Ministry of Geology and Minerals, Sun Daguang, claims that with increased prospecting in the last few years, China's phosphate reserves now rank first in the world. Whatever the actual size of its known and potential reserves, China's present phosphate processing capabilities fall far short of demand, while the substantial progress that has been made in this area points out the severity of the problems that still remain. Since 1949 China has developed 181 mines and increased its phosphate concentrate production from 10 kt (11,000 st) to 10.86 Mt (11.97 million st). By the 1980s, China was the third largest chemical fertilizer producer in the world-although this claim is slightly misleading as China's nitrogen/phosphate potassium ratios are far from average world ratios and even further from US standards. According to the Sixth Five Year Plan promulgated in 1982, the country's development plans emphasize the expansion and upgrading of key energy and industrial sectors, including that of fertilizer production-specifically phosphate and potash. Within the framework of the plan, the Ministry of Chemical Industry's development priorities are to: • Increase potash production by 150% to 50 kt (55,115 st). • Raise phosphate fertilizer production 21.2% to 2.8 Mt (3.1 million st), 46 kt (50,705 st) of which will come from new projects constructed and completed within the Sixth Five Year Plan, with projected new production of phosphate concentrate and complex fertilizer in the next decades totaling 500 kt (551,146 st). • Commence work to increase phosphate ore production by 8.33 Mt (9.18 million st). Facilities for 2.43 Mt (2.68 million st) will be completed and come on stream by 1985. • Commence work to increase iron pyrite ore production by 3.69 Mt (4.07 million st), facilities for 2.9 Mt (3.2 million st) will be completed and come on stream by 1985. • Verify 600 Mt (661 million st) of new phosphate ore reserves. Since the promulgation of the Sixth Five Year Plan, Chinese authorities have announced that 70 key construction projects will receive top priority in the implementation of the plan. These projects include five in the chemical industry area, including the construction of four fertilizer plants in Urumqi (Xinjiang), Zhenhai (Zhejiang), Beijing, and Lucheng (Shanxi), and a pyrite mine in Yunfu (Guangdong). In addition, by 1985 the state will expand or construct three major phosphate mines: Wangji in Hubei, Kaiyang in Guizhou, and Kunyang in Yunnan. Fertilizer Ratios In 1982, China's fertilizer production was slightly higher than 12 Mt (13.2 million st) and consisted of 80% nitrogen, 19% phosphate, and 0.19% potassium. By 1985, state officials project that fertilizer production will reach 13.4 Mt (14.8 million st) and consist of 78.4% nitrogen (10.5 Mt or 11.6 million st), 21.2% phosphate (2.8 Mt or 3 million st), and 0.39% potassium (52.3 kt or 57,605 st). To attain the world average using the country's 1985 projected production level for nitrogen, China will have to double its 1985 phosphate production to 5.76 Mt (6.35 million st) and increase its 1985 potassium production almost 80 times to 4.1 Mt (4.5 million st). These numbers demonstrate the seriousness of the fertilizer production problem in China today and the long-term nature of the problem's solution. Development Examples Yunnan is the third largest phosphate-rich province in China with verified deposits of 1.9 Gt (2.1 billion st). Despite this abundance, the province only mines around 3 Mt (3.3 million st) of phosphate rock annually. In June of this year, Yunnan announced its intention to initiate 39 development projects within the next two and a half years, requiring an estimated $200 million worth of foreign investment. The three areas receiving the most emphasis will be:

Jan 9, 1983

By C. Timothy Shaw, Michael Karmis, Hans de Ruiter

The Society of Mining Professors/Societät der Bergbaukunde was established during a meeting hosted by the Montanuniversität, Leoben, Austria, in 1990. Since then, the Society has primarily functioned as a European entity of senior academics in the mining engineering discipline. The Society is considered the natural successor of the historic Societät der Bergbaukunde, formed in the early 18th century and recognized as the world’s first international scientific society. At the 14th Annual General Meeting of the Society, in Milos, Greece, 2003, a decision was made to examine the role of the Society in global minerals education, to reassess its vision and membership guidelines and to develop the future direction of the organization. A special Planning Subcommittee developed a plan of action to allow the Society to transform and position itself as the premier global voice of the academic minerals disciplines and to lead the effort of restructuring minerals education. The new vision calls for reconstituting the Society as a vibrant global society, representing the majority of minerals academics and making a significant contribution to the future of the minerals disciplines. This paper will present the history, vision, goals and action plans of the Society to help ensure that the necessary scientific, technical, academic and professional skills are available for the sustainable supply of minerals to mankind.

Jan 1, 2005

By Rolland L. Blake

The Bureau of Mines is investigating the potential for in situ leach mining "(ISM) of gold and silver mineralization. This preliminary study examined samples from several types of deposits using light optical microscopy and the electron microprobe to characterize the ore and gangue minerals and their microscopic characteristics, including the spacial relations between the target minerals and likely natural fluid channelways. Low grade disseminated deposit types from the western U.S. were found to contain fracture-hosted or matrix-hosted gold and silver minerals, some of which are encapsulated by quartz or pyrite. Geologic features readily observed microscopically include ore and gangue mineral identity, size, and their association with each other and with fractures. Successful ISM application to gold and silver deposits needs this data to: (1) select the proper lixiviant based on chemical reactivity of the host rock, ore, and gangue minerals, (2) determine potential permeability characteristics when designing lixiviant flow patterns, and (3) understand potential problems of the lixiviant reaching encapsulated ore minerals. Careful examination of the geologic characteristics of each ore body is required because of the observed diversity of characteristics in deposits from the same "class" and even within the deposit itself.

Jan 1, 1989