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By C. H. Bloomster

This study estimated (1) radon and radon daughter emissions from underground uranium mines; (2) the reduction in radon that would be released to the surface by using control techniques such as bulkheads, sealants, backfilling, and positive pressure ventilation; (3) the cost for radon and radon daughter removal from total exhaust air; and (4) total radon and radon daughter discharge for lower occupational exposure limits. For 13 large underground uranium mines, estimated yearly radon emissions from each mine ranged from 900 to 3,400 Ci. The estimated age of air emitted from the mines ranged from 11 to 37 min. Potential radon removal methods for the total mine exhaust were evaluated. The cost of these methods was prohibitive. Diurnal and seasonal changes may affect radon emission over short periods of time, but do not affect the total emissions over the long run. Radon and radon daughter emissions would be little changed by increased ventilation requirements needed to achieve lower occupational exposure limits. The concentrations in the exhaust would be lower, but the total release would be the same

Jan 1, 1984

By Y. Bai, J. J. Liu, D. Q. Li, S. Z. Liu, X. T. Wang

"This paper presents the results of an industrial test using 8 t/d of Baotou concentrate (50% REO) of a clean metallurgical process, which includes: 1. Roasting with H2SO4 at low temperature (220~260 0C) in a batch roasting furnace followed by water leaching to obtain a leach liquor as feed with a yield of >95% RE and Th, recovering F as fluoride, producing a leach residue amounting to 1/3 of an equivalent high temperature residue and containing <0.03% Th and radioactivity < 3×104 Bq/kg compared to the normal high temperature residue containing 0.2-0.3% Th and 1×105 Bq/kg. 2. Separating Th with N1923 and extracting RE by P507 has been completed in mixer-settlers. Test results indicate that the ThO2 product has a purity of > 95% with a yield of 99%, and the RE has a yield of >95%, in which ThO2/REO <5×10-6, and that P507 loaded RE connect straight with separating RE using P507-HCl system. 3. Treatment and multipurpose use of "three wastes" (water, gas and solids) are discussed in some detail."

Jan 1, 2014

By J Watt

The Hidden Valley Gold Project is located in a remote and mountainous area of the Morobe Province approximately 30 km south of the township of Bulolo and approximately 90 km south-southwest of the provincial capital, Lae. The Hidden Valley deposit was discovered in 1984 with the nearby Hamata and Kaveroi deposits discovered in 1987 and 1992 respectively. Reserves (Harmony, 2009) at these three deposits are 42.1 million tonnes of ore containing approximately 2.9 million ounces of gold and 45 million ounces of silver. A further 5.4 million ounces of gold and 84 million ounces of silver are in the resources category. The process plant is designed to treat 4.2 million tonnes per year of gold/silver ore extracted by open cut mining methods. Ore is classified into three ore types according to oxidation state: oxide, transition and primary. The silver to gold grade ratio is high for the Hidden Valley and Kaveroi ores, generally in the range 15 - 20:1, and much lower for Hamata, typically 1 - 2:1: Primary ore is the dominant ore type at Hidden Valley with sulfur grades up to about two per cent sulfur. Oxide and transition ores are more prevalent at the Hamata deposit, but its primary ore has up to five per cent sulfur grades. Variable ore types, particularly in the initial years of operation, high silver to gold ratios and limited plant site area, due to the challenging terrain, present the main processing challenges for this project. This paper describes the operating strategies and process development for the main areas of this circuit, highlighting selections of processes and equipment that achieve cost effective, yet flexible solutions to the treatment of ores from these deposits.

Jan 1, 2009

By J. J. Dekker

Controlling noise has proven difficult in mining, and noise-induced hearing loss (NIHL) remains common. In 2008, a South African Mine Health and Safety Council study focused on small- to medium-sized mines in relation to the milestones set by the industry to prevent NIHL. An evaluation of the compliance of ten diamond, sand, aggregate and Ready mix concrete mines and production sites with standards, legislation and best practice guidelines relating to NIHL prevention was conducted, using a noise compliance audit tool. The findings indicated that all mines surveyed had poor compliance with the international standards, compliance with International Standards Organization standards being the poorest. There was a clear distinction between the small and the medium-sized mines in their compliance with local standards and legislation (ranging from 14 per cent to 66 per cent). The areas of best compliance were audiology and medical examinations. The lower-than-expected compliance was largely attributable to shortcomings in hearing conservation programmes for occupational noise. Initiation of remedial practices in the small- to medium-scale mining sector to facilitate improvements in NIHL prevention and compliance with standards and legislation is recommended. Keywords Hearing conservation, small-to-medium mines.

Jan 1, 2011

By Heribert F. Broicher

By the very nature of mineral deposits the quality of the raw material generally fluctuates and should be known for optimum processing. Early classification, for example, of limestone into road-metal grade or lime grade or of run-of-mine ores into high grade, low grade and waste as well as information for blending or for dosage of reagents are prerequisite for economic processing. Non-contact, real-time and on-line rock identification or assessment of quality parameters can be realised by introducing the analysis of laser-induced fluorescence (LIF) into the mining industry. LIF analysis is an optical method evaluating the basically known photoluminescence properties of matter, however, extending the application into hitherto unimagined fields by use of high-energy pulsed lasers and time-resolved analysis of fluorescence in the ultra-violet, the visible and near-infrared domains of light. LIF analysers and test work in a limestone quarry and a cement plant in Germany as well as in an iron ore mine in Sweden are described. First results of test work are available and proof this technology to be promissing.

May 1, 2002

By Eric Low

Raising capital by issuing debt or equity is necessary in almost every corporation. In the field of corporate finance, the raising of capital is a heavily-studied topic. However, some of what is studied on this topic in corporate finance is not applicable in the mining industry. There are also many financing options that were created for the mining industry such as flow-through shares, prepaid forwards, and royalty sales. The cyclical nature of the industry makes the risk-return profile of financings more difficult to estimate than in other industries. Additionally, the methods used to assess firm value are different than other industries, as the values of orebodies are not included on balance sheets. For precious metals companies, which are a hedge against most other securities, there are additional complications with determining investor expectations and cost of equity. This thesis puts forth a decision-making framework to explain mine financing choices from the perspective of mining companies. The approach is threefold. First, all of the major equity and debt financing instruments available to mining companies are presented and analyzed. Each financing method is assessed on a wide range of criteria. Next, these concepts are applied in case studies of four companies: BHP Billiton, Barrick Gold, Teck Resources, and Noront Resources. For each company, the overall choice of financing methods is shown and analyzed. The effect of financing choices on the weighted average cost of capital (WACC) is calculated. The final section deals with case studies of individual mine finance decisions during the past two years.

May 1, 2011

By Tobias Hansson

The quality of Lime Cement (L/C) columns is to a great extent dependent on the installation procedure. At a site in the south of Sweden, the client reported problems with the installed columns. To evaluate the operator and equipment dependent part of the installation, Hercules Grundläggning AB was appointed as a competitor to the site contractor. The purpose was to install a number of L/C columns with equal installation parameters for both contractors. A total of 65 test columns were installed in June 1999. The geology is a typical Swedish organic soil profile with a top layer of peat overlying gyttja and clay. Two different binders were used in the comparison; blast furnace slag with cement and lime with cement. After installation, the quality of the columns was monitored by penetration tests and a column sampler for extracting whole columns. The column penetration test were performed 28 and 134 days after installation and extraction 134 days after installation. Inspection and tests of the extracted columns showed that by using a fully computer controlled procedure, the contractor produces columns of superior quality and homogeneity.

Jan 1, 2000

Even though the economy of the United States remains in recession ? or not, depending on which economist you listen to ? muicipalities still need improved transportation, water and wastewater transit systems. And they are willing to spend the necessary funds on those systems, provided they are affordable, environ-mentally friendly and sustainable. From June 20-23, professionals in the tunneling and underground construction industry from around the world gathered in Portland, OR to learn new ways of providing those systems using the latest technology available. The North American Tunneling (NAT) conference attracted 803 attendees and 108 exhibiting suppliers of equipment and services.

Jan 1, 2010

By Edelink Efrain Tinoco Falero

Na atualidade a produção e a utilização de DRI estão aumentando nos países desenvolvidos, principalmente devido à redução do preço do gás natural e do sucesso da nova tecnologia de extração de gás de xisto. Os custos operacionais e os problemas ambientais são, efetivamente, os fatores tecnológicos importantes a serem considerados na otimização da produção de DRI. Portanto, o teor de carbono do DRI tornou-se essencial em virtude da capacidade de gerar energia química no banho de aço, complementando assim a eletricidade em FEA, e as contribuições exotérmicas da oxidação de Si e C nos conversores LD. Este trabalho faz parte de um programa completo de cooperação entre a companhia de mineração Samarco e o Grupo de Siderurgia da PUC-Rio, lidando com as equações cinéticas da metalização e carburização simultânea em fornos de redução direta. Para este efeito, o reator foi dividido em três zonas internas: Redução, Transição e zona de resfriamento. Além disso, também foram consideradas três regiões concêntricas: periférica, média e centro. Á partir desses resultados, para um tipo de pelotas RD específico, mistura de gases utilizados nas instalações industriais e similar flui-dinâmica do processo, as equações cinéticas de metalização e carburização foram estabelecidas para cada zona. Um programa computacional METCARB, totalmente baseado nessas equações cinéticas, foi então concebido. Finalmente, uma validação adicional procedeu-se tendo em conta duas corridas operacionais industriais.

Aug 17, 2017

By J. N. Van der Merwe

The principal goal of the research described in the paper was to determine, by measurement of pillar scaling on pillars that have not failed, whether the pillar life prediction method developed by van der Merwe (2003) was valid as it stood or whether adjustments were necessary to the rates indirectly derived from observation of failed pillars. To this end, measurements were taken on over 350 pillars at 13sites on 6 mines. The project was done as a collaborative effort between the University of Pretoria, the Nancy School of Mines and CSIR Miningtek. During the course of the investigation, it was found that the majority of pillars display maximum scaling at mid height, that there was no clear preferential direction of pillar scaling, and that pillar corners do not scale significantly more than the mid pillar areas. The most important conclusion was that the scaling rates found by measurement agreed with the inferred rates found in the previous work. The previously developed procedure for the prediction of pillar life spans consequently requires no adjustment, although the error span is in the region of 20%. It is recommended to do further research into the effect of sealing of panels and, possible chemical changes taking place in the pillars as they age on the scaling rate.

Jan 1, 2004

By P. R. Moyer

"INTRODUCTION The Federal Explosives Act (55 Stat., 863), as amended, was passed by Congress on December 26, 1941, and became effective immediately; it amended the Act of October 6, 1917 (4o Stat., 385). The purpose of the Act was to regulate the manufacture, storage, use, and possession of explosives in order to prevent sabotage and to assure that explosives and ingredients would not fall into unauthorized hands. Under the provisions of the Act, the Director of the Bureau of Mines was authorized to administer its provisions under the supervisions of the Secretary of the Interior.EXPLOSIVES-CONTROL DIVISIONTo administer the Act, necessary personnel were employed in accordance with the appropriation made from a special presidential fund and later by Congress, and the Explosives Control Division was organized as a part of the Health and Safety Branch of the Bureau of Mines constituting the fourth division of that branch. A central office was established in Washington, D. C., and field offices were designated largely at the offices of the Health and Safety Branch throughout the country, and 50 explosives investigators were employed and assigned to work from these offices under the direction of the district engineers of the eight districts into which the United States is divided by the Health and Safety Branch. The territory assigned to each investigator was based on the approximate amount of explosives stored in that area; however, smaller territories were assigned to investigators stationed near the Pacific coast, which was indicated as critical by the armed forces."

Mar 1, 1947

By Edwards A. B

The following note on the mineral association in the ores of the Tennant Creek Goldfield, Northern Territory, is largely based on Mineragraphic Reports Nos. 49, 89, 117 and 193 of the Council for Scientific and Industrial Research. These reports are the results of the examinations of auriferous specimens from a number of mines of the goldfield and are now supplemented by the examination of further specimens from Mt. Samuel forwarded by Mr. V. G. Martin.The Tennant Creek Goldfield lies in the central portion of the Northern Territory, about Lat. 190 35&apos;, Long. 1340 15&apos;, on the Overland Telegraph Line and about 369 miles north of Alice Springs. It comprise an area extending about 50 miles east and west, by 30 miles north and south.The geology of the goldfield has been described by Woolnough. (2)The rocks of the area are of pre-Cambrian age, and consist of talcose, chloritic, micaceous and siliceous schists of sedimentary origin, interbedded with flows or dykes of schistose quartz porphyry, and of granites which were intruded subsequent to the regional metarporphism of the area. The rocks are moderately folded, but the beclding tends to be obscured by a pronounced east-west cleavage. The most continuous orebodies run east and west, parallel with this cleavage.Numerous lenses of hematite occur in the schists, with their long axes, parallel to the cleavage, and the gold values of the field are frequently associated with such hematite bodies. The dimensions of these hematite bodies are variable but rarely exceed a length of 300 ft., with an average thickness between 10 and 30 ft.; the original vertical dimensions are thought to be comparable with their length. The lenses tend to occur in groups when they are arranged en echelon both horizontally and in depth; and erosion has exposed individual lenses to different degrees, ranging from incipient exposure to complete removal. The existence of unexposed hematite lenses at depth has been proved by geophysical surveys, coupled with drilling tests. (3)A few of the bodies are pipe-like. Many are surrounded by a casing of brecciated rock, composed of fragments of hematite and shattered country rock, and presumably caused by subsequent earth movements which crushed the country rock against the resistant hematite bodies. In the early days of the field most of the important gold occurences were found within these crushed zones, or, to a less extent, within the hematite bodies themselves.These occurrences appeared to be associated only with those hematite lenses which were intersected by quartz veins or other lines of weakness, of later origin than the crushing. This led Woolnough to think that the introduction of the gold and attendant bismuth was subsequent to the...

Jan 1, 1942

By M J. Shearer

An investigation into the reliability of the data being collected at the Mount Isa Mines site operated by Glencore in Queensland allowed on-site ventilation personnel to scrutinise pressure and volume measurements collected from the primary surface fans. The investigation effectively identified discrepancies being reported to the on-site remote monitoring system. The difference between the real-time and static measurements on the P63 RAR shaft identified that the in&#160;situ differential pressure transducer and piezo annubar system was not operating correctly. This indicated a deficiency of approximately 30&#160;per&#160;cent reporting back to the remote monitoring software versus the live readings measured with the Pitot tube bomb and ALNOR AXD610 pressure micro-manometer.Constant monitoring of an operations ventilation network is imperative to ensuring that the underground atmosphere provides a safe and healthy workplace. Further benefits to real-time monitoring allows for the early indication of network failures and promotes increased availability. An innovative approach to out engineer and improve the existing measuring equipment from the 1970s was sought.The use of ultrasonics in the mining industry is not new with ventilation management systems (VMS) equipment available within the marketplace. The introduction and implementation of a reliable product for real-time monitoring was a challenge to overcome due to limited access and suitable measuring points within the mine. The available equipment on the market through mainstream suppliers was not suitable for the unique application required due to the in&#160;situ installation of the surface fans. A solution was identified in the oil and gas industry through collaboration and innovative thinking. This paper describes the sustainable approach to implement a reliable air flow monitoring system on-site.CITATION:Shearer, M J, 2017. Case study – an analysis of reliability and efficiency: ultrasonic versus annubar technologies, in Proceedings Australian Mine Vent Conference 2017, pp 51–56 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Rick Wilkins

The stability of steep embankments is a major safety issue in open pit mining, highway passes, and earth filled dams. A failure in any one of these situations could mean a loss of very expensive equipment, a long term inconvenience, and more importantly, a loss of life. These possible catastrophes could be avoided by installing a reliable real time monitoring system. Robotic total stations (RTSs) give one possible cost effective solution to creating a near real time monitoring system. Repeated surveys at predetermined time intervals can automatically generate warnings if slope movements exceed a preset tolerance level. The variation in atmospheric refraction, combined with possible instabilities in reference targets, can make a monitoring system based on RTSs produce false alarms. A methodology has been developed at the Canadian Centre for Geodetic Engineering (CCGE) for reducing these systematic error effects. The methodology has been realized in the creation of a software package that has been successfully implemented at large earthen dams in California and at an open pit mine operation in British Columbia.

May 1, 2002

The design, specification, and performance evaluation of the Communications and Location portions of a Coal Mine Rescue and Survival System are described. The work was performed as part of a nine month effort to develop a mine rescue and survival system using existing technology and state -of-the -art hardware as recommended by the National Academy of Engineering. Three basic subsystems were developed, one for survival, one for communications/location and one for rescue. This report and related equipment manuals describe only the Communications/ Location Subsystem which was designed, fabricated, and tested by the Westinghouse Georesearch Laboratory in Boulder, Colorado. Two basic technologies were used. Electromagnetic signals propagating through-the-earth provide voice downlink and coded beacon up-link communications. Seismic methods were developed to provide means for locating trapped miners. Seismic signalling also provides a backup means for communications. Parallel development programs for the electromagnetic and seismic portions of the system were conducted. The resulting hardware and software have been partially tested in coal mines and under simulated emergency conditions in order to evaluate system performance. The results of these tests are discussed. Further testing is recommended in order to establish quantitative performance limitations tinder a variety of environmental conditions and to develop methods for improving system performance.

Jan 1, 1971

By R J. Johnson

The development of "SANFO" has provided the Mining Industry with a LOW COST HIGH GAS VOLUME, VARIABLE DENSITY, Blasting Agent which can be blended "On Site" in a simple Agitator mixing and charging system by mine site employees.

Jan 1, 1996

By Brendan Demich, Joseph McGuire, Emily J. Haas

Near misses recorded and reported by workers can provide awarenessto the potential causes of injury and prompt safety management initiatives. Although most companies require near-miss reporting, it is unclear what the value of these reports are, if any, and how they influence subsequent actions or controls to reduce on-the-job risks. Researchers at the National Institute for Occupational Safety and Health (NIOSH) conducted a case study with an aggregates company in which near-miss reports were analyzed at each of their locations over an entire quarter during the summer of 2018. Within that quarter, workers recorded 249 near misses. Of those, 167 were valid near misses that occurred at work. Researchers coded the reports using a qualitative 5 × 5 risk matrix. Of the 167 near misses, 19% were deemed low risk, 25% moderate risk, 30% high risk, and 26% critical risk. Several patterns in the near-miss incidents were documented, including classification of incidents and common corrective actions referenced (i.e., elimination/substitution, engineering control or redesign, work process/procedures, and personal protective equipment). The analysis provides insight into ways that risk communication and management programs can be improved to reengage workers and their situational awareness on the job.

The Phoenix mine on the Mararoa Reef at Norseman, Western Australia, provides an outstanding: AUstralian instance of the recurrence of payable ore beneath the bottom of an abandoned mine, and an interesting and instructive example of the development ofideas with regard to ore recurrence in a particular district. The Mararoa Reef is the most productive of several hypothermal goldquartz vains in pre-Cambrian basic volc81olics which strike northsouth and dip on the average, 45 degrees east. The Phoenix minewas abandoned at 500 ft. vertical depth after producing 342,000 tons of 9.9 dwt. recovery grade (equivalent to nearly half of the total production of the Norseman field) from a 2,500 ft.. long, horizontally disposed oreshoot, which is reported to have had an ore outcrop only 30 ft. in length.Interest in the field was revived in 1933, and by 1941 new ore mined and developed on the Mararoa Reef by Central Norseman Gold Corporation N.L. amounted to approximately 700,000 tons of 6.7 dwt. recovery grade. In the same period another oreshoot of similar size and grade was developed by Norseman Gold Mines N.L., south of the old Mararoa company&apos;s site. As shown by the plans, the ore occurs in discontinuous shoots. The intervening area of shear is poor in quartz as well as in gold. Geological work on behalf of Western Mining Corporation Ltd., and Central Norseman Gold Corporation N.L. has been in progress in the mine and in the field more or less continuously from 1913 to 1941 and again since 1946. This paper describes the successive advances in the understanding of the exploratory problem up to late 1941, to which several investigators have contributed. It is published by permission of the Board of Directors of Central Norseman Gold Corporation N.L., owners and operators of the Phoenix and other mines.Development of the Prospect.In 1933 Western Mining Corporation acquired an option over the Phoenix property and adjacent leases. H. E. McKinstryl visited the mine and recognised that the ore occurred primarily on the flatly dipping sections of the vein, as distinct from the steeply dippingsections, in a wide shear zone with reverse movement. Many of the flatly dipping fractures were seen to exhibit tension phenomena and to link one shear plane to the next below on the footwall side. The flat links carried much more quartz than the steeper shears.Later, H. J. C. Conolly, assisted by J. D. Campbell, examined the prospect and by contouring the vein with reference to an inclined...

Jan 1, 1950

By D. J. McLaws

"Recent innovations in metal smelting technology utilize continuous oxygen-enriched smelting and converting processes which are capable of producing off-gases containing up to 60% SO2 or more. Other SO2 recovery processes, involving solvent absorption and steam or vacuum regeneration, can produce off-gases with SO2 concentrations nearing 100%.Processing of these high-concentration SO2 off-gases in conventional sulfuric acid plants can cause excessively high catalyst bed temperatures and poor SO2 conversion. In order to avoid these problems, a conventional acid plant design must dilute these high SO2 process gasses with dilution air in order to provide the required oxygen to effectively convert the SO2 and provide a heat sink (via the inert N2) such that the exothermic reaction, SO2 + ½ O2 ???SO3, does not exceed the temperature limit of the catalyst or the converter vessel.MECS, Inc. (MECS) has proven that a high SO2 feed gas design can be a viable option which can increase energy recovery, reduce energy consumption and potentially reduce capital costs."

Jan 1, 2014

By Chas. F. Jackson

The work of the Mining Division is divided among seven sections, each in charge of a supervising engineer, as follows: 1. Metal-mining methods section, the supervising engineer of which is also supervising engineer of the Southwest Experiment Station at Tucson, Ariz. 2. Metal-mining research section. 3. Nonmetal-mining section. 4. Coal-mining section. 5. Mine-ventilation section. 6. Mineral-industries survey section. 7. Electrical section. The names of the sections indicate broadly the fields covered by each, and in the following, pages the objectives and type of work of each section will be summarized briefly and their active problems listed. The work clone during the fiscal year 1937 will also be summarized.

Jan 1, 1937