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By Martha E. Smith

INTRODUCTION Radiation is one of the many agents occurring in our environment that is capable of causing cancers. We are all unavoidably exposed to natural background radiation. If we wish to exploit the beneficial uses of radiation in medicine, industry, and for the production of electricity, some further exposures to radiation are almost inevitable. One needs to ensure therefore, that the standards of radiation protection are safely derived and one would want to understand the mechanism by which radiation might cause cancer and genetic defects. In order to study the effects of radiation one can: (1) analyze human data, (2) perform animal experiments, and (3) do molecular level experiments. Indeed all three kinds of information are needed. This paper will concentrate on the steps required to obtain some of the necessary human data regarding health effects, where the concern is about the impact and consequences of long-term low-level exposures to an agent. Such investigations require some knowledge of work histories, dose histories, health "outcomes", and the personal identification of the individual involved. Three inter-related computer systems have been developed at Statistics Canada which have been designed to permit optimal use of a number of different records for our entire country for such health related research. The development of the Canadian Mortality Data Base, the initiation of the National Cancer Incidence Reporting System, and the development of new computer linkage techniques have helped reduce the cost and increase the scale and efficiency of automated follow-up to produce statistics of sickness or death associated with radiation and other carcinogenic agents in mines. These computer systems have already been implemented, and references will be made to studies currently being conducted using these files and facilities (e.g. a study of all Ontario miners, plus various Canadian uranium, fluorospar, salt and nickel miners). We will also look at the kinds of data that need to be collected now, to improve such studies in the future. DELAYED RISKS - THE STUDY SIZE AND COST Delayed effects on human health, as for example industrially caused cancer, can in general only be detected and measured by following-up the individuals to see what eventually becomes of them. What is not generally recognized is that the relatively low levels of individual risk, about which the public is often concerned, usually requires for their detection that very large numbers of "exposed" and "control" individuals (e.g. 10,000 to 100,000 or more) be followed over a period of two or three decades to determine when they die, what they die of, and whether they contracted cancer or some other disease of special concern. Thus, it is frequently exceedingly difficult to make such investigations cost-effective so that they will be undertaken at all, and as a result very real risks to health can remain undetected or unquantified. THE MANUAL PROCEDURES Follow-up of individuals by epidemiologists has until recently been a largely manual and clerical operation. It has used a diversity of source record files; local, regional, and national. Often the tracing of people has involved letters sent through the mails and visits to institutions, physicians, municipal offices, and former neighbours. Only thus could one find out whether the individuals were dead or alive. Such studies were necessarily small, or else very expensive. Death registrations have, by tradition, provided a valuable tool for the identification of harmful influences in the environment. However, with the increasing mobility in the population, death may often occur far away from the place of exposure to such an influence. Thus, no longer will simple manual searches in a single registry office suffice to inform the investigator concerning the deaths that may have occurred in a study population, especially when that population is large. In the past, manual follow-up to locate the relevant death registration normally required some prior knowledge of the province and year of death in question, so that the alphabetic indexes could he used to direct researchers to the appropriate bound volumes of registration forms. To search manually in this fashion for any large number of death registrations, without knowing in which year or province the deaths had taken place, or even whether they had yet occurred, would be impractical, since each year in Canada there are about 170,000 deaths. DEATH AND CANCER AS SPECIAL ENDPOINTS Much of recent effort has been focused on the organization of the "endpoint" files required to do long-term follow-up studies on a national scale, because that is a function which other institutions are unable to perform due to the confidentiality laws governing the use of such information. Outside organizations generally come to us with detailed "starting" point records which relate to some specific group requiring study. We carry out these epidemiological searches on a cost-recovery basis. The analytical interpretation of results is normally

Jan 1, 1981

By J. Klemenic

This paper presents an analysis of gold production and prices over an extended period. Production patterns are provided for the world as a whole and for the five major producing countries. Gold prices as a function of interest rates, as measured by municipal bond rates, are given for the period 1947 to the present. World gold production has had a phenomenal increase since 1980, with the exception of South Africa, all major producing nations participated in this increase, even though the price of gold generally has been decreasing since the high level attained in 1980.

Jan 1, 1993

By A. T. Yu

The quest for ore in an open pit is fundamentally an earth moving proposition. This thesis is vividly underscored by the rapidly increasing volume of waste to be removed in newer mines, where in some instances waste to ore ratios have reached as high as 20 to 1. Continuing depletion of high grade reserves, greater demand for raw materials, coupled with ever climbing labor costs, have made the problem still more pronounced and the need for more effective means of earth moving in an open pit even more acute. A conservative approach to the problem has been to upgrade the sizes of conventional earth moving equipment such as shovels and trucks. In many open pits, particularly in the C.S., this has been responsible for the generally down- ward trend of earth moving costs. None the less, the investment costs of these machines are high, and their gigantic engines are seldom fully utilized. Moreover, a large number of operators are required and maintenance remains relatively high. Unfortunately most people have felt that no other viable alternative was in sight within today's technological capabilities.

Jan 1, 1973

By A. D. Davis

The former Homestake gold mine at Lead, South Dakota, has been selected by the National Science Foundation as the proposed host site for the Deep Underground Science and Engineering Laboratory. The deep laboratory and associated research campus will be developed at approximately the 7700-ft level. Plans also include the development of the Sanford Underground Science and Engineering Laboratory at the 4850-ft level. After the mine?s pumps were shut off in June, 2003, water levels rose to approximately the 4650-ft level by early 2008. Pumps in the 8150-ft deep mine were turned on again for dewatering in April, 2008. Instrumentation is being installed in the mine to measure water-level declines during pumping, for later analysis of permeability and related hydraulic properties of the formation. Pressure-sensitive transducers and data loggers will provide real-time information on water levels that will be available to interested parties. Quality of the water also will be monitored as it is pumped from the mine. I

Jan 1, 2009

By Harlan N. Barton

A commercially available portable X-ray spectrograph, lightweight and of rugged construction for vehicle or field camp use, was used for the determination of Ba, Cu, Fe, Mn, Pb, Rb, Sr, and Zn in stream sediment geo- chemical samples. Investigations showed a relative standard deviation of 1-3 percent, detection limits of approximately 100 ppm; and significant matrix effects. Coefficients of correlation greater than 0.9 were obtained between portable X-ray and emission and atomic- absorption spectroscopy analyses. A geochemical map of a known mineralized area showed good agreement with maps prepared by other methods of analysis and sample media.

Jan 1, 1980

By R. Woods

"Comments on the paper ""Formation of hydrogen peroxide by chalcopyrite and its influence on flotation,""by A. Javadi Nooshabadi and K. Hanumantha Rao (Minerals & Metallurgical Processing, 2013, Vol. 30,No. 4, pp. 212-219)The formation of hydrogen peroxide from water during the grinding of chalcopyrite in a nitrogen-sparged environment, as reported by Javadi Nooshabadi and Rao (Minerals & Metallurgical Processing, 2013, Vol. 30, No. 4, pp. 212-219), is questioned on the grounds that oxidation of water by the mineral is unlikely to be thermodynamically feasible. It is argued that it is more likely that any peroxide that had been formed would have been generated from residual oxygen in the nitrogen-flushed system than from the oxidation of water.The formation of hydrogen peroxide by finely divided pyrite had been reported by a number of authors (Borda et al., 2001; Borda et al., 2003; Cohn et al., 2006; Schoonen et al., 2006; Schoonen et al., 2010; Jones et al., 2011; Javadi Nooshabadi et al., 2013). That hydrogen peroxide is formed in the presence of oxygen in solution can be comprehended from wellestablished mechanisms. Pyrite in aerated solution is known to oxidize by an anodic process that is coupled with the cathodic reduction of oxygen (Holmes and Crundwell, 2000). The latter process has been shown to occur through the formation of hydrogen peroxide (Biegler et al., 1975; Ahlberg and Broo, 1996). The pH dependence of cathodic oxygen reduction at other sulfide minerals, including chalcopyrite (Biegler et al., 1977; Rand, 1977), implies a similar mechanism at these surfaces."

Jan 1, 2015

By L. M. Anisdahl

Ventiflex is a flexible ventilation duct system with a global market within mine and tunnel ventilation. The system is distributed in a wide range of qualities and dimensions. It is very important that ventilation systems are designed correctly in mines and tunnels. An incorrectly dimensioned system might result in bad air quality and too high costs. The objective of this study has been to assess some important design parameters for ventiflex comprising the friction loss factor for the duct wall itself, as well as the shock loss factors and the leakage factors for the different couplings systems. This has been obtained by carrying out a large scale experimental program on ducts with all the three different couplings: Velcro, zip and steel-ring. Pressure profiles and air flow rates have been measured, and based on these data the different factors have been calculated. The following results have been obtained: A friction factor l = 0,012 (K = 10) for the duct wall, a shock loss factor z = 0,0125 for velcro- and zip couplings, a shock loss factor z = 0,005 for steel-ring couplings, and a leakage factor f* = 0 mm2/m2 for all three coupling types. The latter result proves that no leakage is possible for a correctly installed duct with proper alignment. The results also confirm that ventiflex complies with class S, or better, according to the SIA-norm. However, whether ventiflex should be designed as class S, A or B according to the SIA-norm, depends on the particular application.

Jan 1, 2009

By C. T. Holland

Coal mining has been an important industry in the Appalachian area for many years. This is particularly true in the northern part of the area, namely, in Pennsylvania, West Virginia, and Ohio. Also, in the south a great deal of mining activity has been carried on in Alabama, Kentucky, and southwest Virginia. Some of the by-products of this activity has been the production of mineralized water from the mines in copious quantitites. The southern Appalachians have been somewhat more fortunate in that the water there has had a considerable amount of alkalinity in it, which has to a large extent eliminated some of the more undesirable aspects of mine drainage. Northern Appalachia, including central and western Pennsylvania, the Monongahela basin in West Virginia, and the Appalachian area in eastern Ohio have not been so fortunate in that coals in those areas and the top and bottom rock have, in many cases, shown considerable quantities of pyrite, and the water does not carry the carbonates found farther south.

Jan 1, 1969

By Renfeng Song, Shaoyan Wang, Zhiqiang Zhang, Ke Guo

Leaching titaniferous magnetite concentrate with alkali solution of high concentration under high temperature and high pressure was utilized to improve the grade of iron in iron concentrate and the grade of TiO2 in titanium tailings. The titaniferous magnetite concentrate in use contained 12.67% TiO2 and 54.01% Fe. The thermodynamics of the possible reactions and the kinetics of leaching process were analyzed. It was found that decomposing FeTiO3 with NaOH aqueous solution could be carried out spontaneously and the reaction rate was mainly controlled by internal diffusion. The effects of water usage, alkali concentration, reaction time, and temperature on the leaching procedure were inspected, and the products were characterized by X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy, respectively. After NaOH leaching and magnetic separation, the concentrate, with Fe purity of 65.98% and Fe recovery of 82.46%, and the tailings, with TiO2 purity of 32.09% and TiO2 recovery of 80.79%, were obtained, respectively.

Jun 16, 2021

By S. G. Ozkan

Boron minerals of economic importance are primarily colemanite, tincal, and ulexite. Turkey and the United States are the leading producers of boron minerals and compounds. Other production includes datolite in Russia and synthetic colemanite in Chile. This paper will discuss various types of chemical and physical treatments of boron ores to produce the marketable minerals and compounds that are consumed in commercial products.

Jan 1, 1995

By K. Hopperstead

Ventilation planning in trackless metal mining is often taken for granted. This paper highlights the trials of planning and executing the ventilation design for Bog Zone at the Lisheen Mine. Ventilation planning for Bog Zone started at the feasibility study stage in 2003; subsequent design changes continued until 2006. In August 2006, the development of the Bog Zone ore body was accelerated through the use of contractors; in addition, the Lisheen equipment fleet was revised based on a larger load and haul fleet. As a result, the circuit was reviewed in terms of changes in design conditions and best practices. This review resulted in a 40% increase of total airflow required to mine Bog Zone. Resources utilized to design the circuit include: external review, computer modeling, and in-house Lisheen planning and operational staff review. The final ventilation design configuration was adopted in 2007, after modeling and evaluating 30 different scenarios, resulting in a better distribution of airflow, optimized secondary escape way, reduced contaminants, and a total power reduction. The value of investment in computer modeling of primary ventilation circuit and planning for staged implementation should never be underestimated.

Jan 1, 2009

By Alexandru Corneliu Stematiu, Catalin Popescu, Radu Sarghiuta

"The tunnel sector is excavated into a rock mass heavily affected by tectonics, defined as a regional fault. The rock around the tunnel support undertakes the non – elastic deformation and gradually detaches from the rest of the non affected rock mass, moving inside of the excavated area and tending to fill up the whole space. The initial solution of using stiff support consisting in double steel ribs I12 with circular shape in the upper part and straight vertical pillars in the lower part has proved to be inadequate. Based on the calculations of the subsidence phenomena and a mathematical model, the proposed alternative support was provided by special circular steel ribs – SG-23 –that allows a limited rib deformation (by relative slip between the arch segments) in order to mobilize the contact between the rock contour and the inner face of the rib - not only for the deformed rib but also for the neighboring ribs. 1. INTRODUCTION Hydropower development of Jiu river in Romania, in the narrow gorge sector includes two diversion HPP and a small hydro plant that provides the minimum required flow downstream: CHE Dumitra , CHE Bumbesti and MHC Livezeni (Table 1. Hydropower parameters).The Livezeni intake reservoir is provided by a gated dam located 1250 m downstream of merging point between Jiul de Vest river and Jiul de Est river. The dam is equipped with three radial gates with flap gates with a span of 12 m each and the height of (6 + 3) m. The longitudinal profile of Dumitra head and the location of the gallery zone that is the subject of the paper are presented in Figure 2. Longitudinal Profile – Dumitra Head."

Jan 1, 2016

By Cleophus Short

[Of the many occupations in and about the coal mines, those of the haulage crews are among the most hazardous. Statistics ship that the second greatest number of fatalities about the coal mines occur during haulage ion and through the use or misuse of haulage equipment. During the five year period between January 1, 1957 and January 1, 1962, the m stone mine had a. Sack haulage frequency of 4098 and mined 3, 541,939 toads per haulage fatality. Coal mire haulage is similar in respects to railroading. We gee very serious consideration to the instillation of tack and to the selection of the haulage crews. In doing this, we are attempting to have our coal mine haulage as. Safe as that of the railroads.]

Jan 1, 1963

By M. R. Grundy

The Robinson project is based on the porphyry copper and gold deposits in the Robinson Mining District, near Ely in Eastern Nevada. The district was mined from the late nineteenth century to 1978 by Kennecott Copper Corporation and its predecessors. Operations ceased when falling copper prices in the late 1970's made their outdated mill and smelter complex at McGill uneconomical. In October 1991, Magma Copper Company (Magma) acquired the many claims that cover the known porphyry copper deposits in the district These occupy a disturbed area about nine miles long and three miles wide between the towns of Ely and Ruth. Magma proposes to build a copper / gold mine and concentrator and expand the existing gold leaching facilities. Several pits, previously mined by Kennecott Copper Corporation, will be enlarged; the use of larger, more modem equipment will result in higher productivity and lower operating costs in general. ICF Kaiser Engineers, of Oakland, California, were awarded the con-tract for detailed design of the process facilities, which was essentially complete by the end of 1993. The project at present is awaiting completion of the environmental permitting process; state air and water permits are in hand, and the Bureau of Land Management's (BLM) current schedule indicates that the final obstacles to construction will be cleared by early fall of this year.

Jan 1, 1994

By D. Bogunovic

The objective of this research was to conduct field-scale experiments at an operating surface coal mine in order to determine the impact of the bucket fill factor on dragline production rate and energy consumption. Data collected from a dragline monitoring system were recorded in a specifically designed software tool and the relationship among these parameters was established. an algorithm for the determination of the ?best? fill factor was developed and integrated in the software. It was determined for the analyzed dragline in the mine that energy consumption in the digging phase can be reduced by 36% and production rate can be increased by 1.4% for a bucket fill factor of about 80%, a fill distance of 19.8 m (65 ft) (i.e., 3.1 bucket lengths) and a bucket fill time of 15 sec. the method developed and applied in this study may help dragline operators to determine the fill factor that will increase production rates and reduce energy consumption in specific surface coal mines. Mining Engineering, 2011, Vol. 63, No. 8, pp. 48-53. Official publication of the society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By John Hanna

The Mineral Resources Institute (MRI) has developed a unique process for selective fatty acid flotation of phosphate minerals from siliceous ores. The process takes advantage of preferential adsorption and high reactivity of fatty acid collectors towards apatite over silica surfaces under slightly acidic conditions of pH 5-6.5. The process was successful in upgrading various phosphate samples from Florida and North Carolina containing 7.7-15.3% P205 and 62.3- 77.2% Insol to concentrates assaying 28.1-33.1 % P205 and 4.1-9.9% Insol with high P2O5 recovery of 81.8-92.2%. Depending on the type of silica impurities present one or more cleaning steps, with or without sodium silicate, would be required to improve the grade of the rougher phosphate concentrate.

Jan 1, 1992

By L. Lacerda

Spray-on ground support membranes (GSM) or thin support liners hold today perhaps as much potential to impact underground (u/g) ground support operations as dry and later wet-mix shotcrete when introduced to mining in the latter part of the 20th century. This emerging technology has come a long way from the time the first single component experimental coatings were tested in the mid-1980s. Due to a number of factors, including occupational health risk and mine safety regulations, it has taken quite some time for the development of non-hazardous membrane products. However, at this junction most existing u/g mines that employ more conventional forms of ground support could benefit from evaluating GSM technology as a means of improving safety and the bottom line. The same is especially true for future mine developments. This paper describes Master Builders Inc.’s CS1251 GSM product and its implementation. It discusses the situations in which GSM may replace other forms of ground support. Furthermore, it evaluates GSM costs & safety issues and looks at present applications and the potentially bright future of this technology.

Jan 1, 2002

By Frank P. Frandina, Diane R. Hirsch, David P. Field, Colin R. Weeks

To accommodate growth in air service and to follow the Master Plan for long-term airport development, the Metropolitan Washington Airports Authority established thed2 Development Program at Washington Dulles International Airport. A sub-surface Automated People Mover (APM) System is under construction to replace the Mobile Lounges as the primary people mover system at Dulles. To minimize disruption to airport operations the majority of the APM System’s crossings of Taxi lanes will be undertaken using Tunnel Boring Machines (TBM) or the New Austrian Tunneling Method (NATM). This paper explores the planning and design of these shallow tunnel segments for future generation aircraft loads, within the constraints of minimal construction access under post 9/11 security requirements and the context of the overall airport expansion program.

Jan 1, 2005

By Se-joon Kim, Jong-hwa Chun

"‘Gas hydrate’ is the common term for a solid material formed from the combination of various gases as ‘guest’ and water as ‘host’. A series of large-scale scientific drilling and coring programmes conducted since 2000 revealed that natural gas hydrate exists in a wide variety of accumulations in the sediments. The scaled-up onshore and offshore field production tests during the last decade show that gas production technology will be realized to make gas production from gas hydrates viable in the future, recognizing its potentials as one of the future sustainable energy resources.The total produced gas was approximately 470 m3 by the hot water circulation method over 6 days of operation in the permafrost-associated Mallik 2002 project in the Mackenzie Delta of Canada. In the Mallik 2007-2008 project, the gas was successfully produced stably by the depressurization method for 6 days, up to 13,000 m3 cumulatively. The depressurization method applied in the Mallik test was shown to be an effective way to produce gas from gas hydrates. The Alaska field trial to inject mixed gas of CO2 and N2 to exchange CH4 in 2012 was successfully done for the first time to produce maximum 1,270 m3 per day. A remarkable achievement was made by Japan when it completed its first offshore production test in the Eastern Nankai Trough, producing approximately 120,000 m3 of methane by the depressurization method over 6 days in March 2013. The technical challenges and scientific uncertainties obtained from Nankai Trough production test provide Korea with more considerations as to the aspects of well completion, reservoir formation and seafloor stability, sand control, flow assurance, environmental monitoring, and etc., due to the different geological setting and geomechanical properties of the Ulleung Basin in Korea."

Sep 1, 2014

By Mary Nelima Ondiaka, Oladunni Oyelola Alabi, Fatai Olufemi Aramide, Francis Gitau, Talabi Henry Kayode

Iron ore is essential in steelmaking but high-grade ores have diminished, making it necessary to turn to low-grade ores, which need further beneficiation to upgrade the iron content. Biobeneficiation techniques such as bioleaching, bioflotation and bioflocculation have proven successful in iron ore processing. Consequently, these methods have emerged as sustainable alternatives to conventional beneficiation. The biobeneficiation processes occur in mild conditions using bioreagents and biosurfactants derived from microbes, and offer a reduction of chemicals used in processing. This potentially offers methods that are relatively energy efficient, cost effective and environmentally friendly while tackling the constraints of dwindling high-grade iron ore resources.

Sep 1, 2024