Search Documents

By Martin H. Stanczyk

The Bureau of Mines studied continuous closed-circuit attrition grinding of a coarse commercial filler-grade kaolin to produce paper-coating-grade clay having a particle size analysis of at least 70 percent minus 2-micron equivalent spherical diameter (esd). The coarse clay, containing about 12 percent minus 2-micron-esd material, was ground in a Bureau-developed 10-inch-diameter attrition grinder in closed circuit with a 5-foot-diameter bowl classifier. In the best test, a finished product containing 82.7 percent minus 2-micron-esd material was obtained when grinding 20 pounds of raw clay per hour at percent solids with a 100-percent circulating load. Energy consumption was about 341 kilowatt-hours per ton of clay feed, or 487 kilowatt-hours per ton of minus 2-micron-esd material produced. Closed-circuit grinding gave some-what greater particle size reduction and lower energy consumption than either batch or continuous open-circuit grinding.

Jan 1, 1965

By E. C. I. Hammerbeck

"Geological controls and constraints in space and time define the milieu of the nickel deposits of Southern Africa. Primary, magmatic deposits are of two types, e.g. synvolcanic or syntectonic deposits confined to certain orogenic domains, and those related to intracratonic, post-orogenic magmatism, e.g. the Great Dyke, the Bushveld Complex and the Insizwa intrusion. Epigenetic and supergene deposits form a separate, unrelated group and are of minor economic importance.The metallogenic evolution of syntectonic nickel deposits is particularly well illustrated in the Zimbabwean Province, where the relationships between Archaean greenstone development and nickel mineralization are best illustrated. Volumetrically subordinate, nickel-poor greenstones in the 3500 m.y. old Sebakwian Group are followed by more common komatiite development in the Lower Greenstones (3000 m.y.), and, finally, by very significant komatiites with important nickel mineralization in the 2700 m.y. old Upper Greenstones of the Bulawayan Group. Comparable nickel mineralization is not known in the Raapvaal Province, in spite of ubiquitous komatiitic magmatism of the Onverwacht Group (3500 m.y.) and other greenstone sequences. No komatiitic rocks younger than about 3200 m.y. are known in this region, orogenic activity in the Kaapvaal tectonic province having ceased at about 3100 m.y., whereas the Zimbabwe Province remained tectonically active until at least 2600 m.y.The tectonic environment, host-rock petrology and mode of emplacement, as well as some details of the nickel mineralization, are the parameters employed to classify the Southern African magmatic nickel deposits. A rating of the deposits is introduced that reflects the original resources of the deposit, its average nickel content, its mining history and potential to facilitate ready comparison with and assessment of the nickel deposits listed in the classification, as well as some important nickel deposits worldwide."

Jan 1, 1984

By D. H. Xiong

Low grade oxidized iron ores are usually not economic to utilize. However, the development of SLon magnetic separators and other new technologies make the process cost lower and lower. In this paper, several low-grade oxidized iron ore process flowsheets are introduced. The key procedure is that at the early stage, SLon magnetic separators are applied to discharge as more tails as possible with very low cost, only a small portion of rough concentrate going to the cleaning stage, showing the new technologies are profitable for such iron ores.

Jan 1, 2014

By Sara Jane Boles

The purpose of this Bureau of Mines investigation was primarily to isolate and examine the effect of liquid content upon the apparent porosity and bulk density of compacts pressed from high-purity, fused aluminum oxide, and, secondarily, to study the actual mechanism by which the liquid content affects the bulk density. No attempt was made to approach the theoretical maximum density of the oxide by introducing additives, particle packings, or similar variables; instead this study is an intercomparison of the bulk densities obtained as functions of the water contents of the compacting mixtures. Water content was varied from 7 percent to 25 percent, on a total-weight basis. The data gathered indicated a well-defined optimum water content for obtaining minimum apparent porosity and maximum bulk density, under the conditions of the experiment. During the course of this study, a number of additional variables in the forming process were discovered and are introduced in this report, although a thorough evaluation was found to be beyond the scope of this present investigation.

Jan 1, 1963

By João Batista Conti de Souza

A utilização de fundentes como fontes de CaO e MgO na carga de altos fornos é uma prática operacional bem conhecida e estabelecida pelos produtores de ferro primário na siderurgia mundial. As práticas podem ser encontradas nas literaturas através de trabalhos publicados onde são descritos e apresentados os respectivos benefícios obtidos. A muito que os produtores de ferro primário, pela rota alto-forno, tem se esforçado nos estudos e desenvolvimentos de cargas elaboradas alternativas através de acordos de cooperação técnica junto aos centros de pesquisas e universidades. Tais acordos visam a melhoria da performance dos aglomerados e dos reatores de redução. A dificuldade em produzir pelotas auto - fundentes, com garantia da manutenção das propriedades necessárias e que favoreçam o processo de produção de ferro primário via alto-forno, tem sido o desafio no que se refere á avaliação das diversas formas de amenizar os efeitos detrimentais da adição de fundentes, contendo altos teores do composto MgO, nas etapas do processo produtivo de pelotização, garantindo assim uma composição química, as características físicas e metalúrgicas do produto final (pelota queimada). O plano de pesquisa visou o desenvolvimento de um “novo produto”, pelotas de minérios de ferro auto - fundentes com alto teor de MgO com características superiores para suportar às solicitações impostas no próprio processo de sua produção, no manuseio e no atendimento às solicitações durante as etapas de redução e amolecimento e fusão nos altos fornos, quando comparadas ao uso em substituição as adições de fundentes ricos do referido composto.

Aug 1, 2018

By E. W. Felegy

Since 1920, the Bureau of Mines and, other agencies have conducted numerous investigations of methods of communication for use in mines in times of disaster or emergency. The results of these investigations have been reported in various publications (3, 4; 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16). In November 1944, the Bureau of Mines resumed the study of emergency underground communications. Until March 1946, the program was directed toward reexamining methods of underground communication that indicated possibilities of success. Since April 1946, the principal interest of this investigation has been in methods of application of radio to communication in mines, low-frequency radio seeming to offer the most promise as a successful method of emergency mine communication. Results achieved in reexamining other methods and in the investigation or the application of low-frequency radio between November 1944 and September 1946 were reported previously in a publication entitled "Some Studies on Emergency Mine Communications".

Jan 1, 1948

By Lawrence F. Rooney

One of Edgar Allan Poe's stories that haunts my subconscious is the Masque of the Red Death. These days, whenever I join a group like this, especially during the cocktail parties, I see myself and others as those mythical swingers seemingly isolated from the plague. The world, but this country especially, has had a ball plundering, spending, and wasting its natural resources for 100 years. And, as in days of yore, it is fitting that we end this ball with spectacular fireworks: trips to the moon, so that our grandchildren, huddled in their caves along the Ohio, will better understand how it all began.

Jan 1, 1970

By B King

Processing expansion options and mining fleet purchases are major cost items that receive due focus in most cost management analyses. If these items are not needed, they can significantly reduce a project’s short-term capital spend and improve profitability and value to shareholders. When conditions change prior to purchasing equipment, the purchase may no longer represent the best decision for the project.This paper outlines a structured approach for making major cost decisions to improve the value of a project, determining which items should be kept and which should be eliminated.CITATION:King, B, 2014. Cost management optimisation, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 7–12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By Vagner Silva Guilherme

Na busca de novas tecnologias para o processo de sinterização de minério de ferro, a recirculação dos gases de saída do processo podem proporcionar algumas vantagens em relação ao processo convencional. Para tal estudo, foi utilizado um modelo multi-fásico de sinterização para a avaliação da recirculação dos gases de saída do processo. Foram analisados cinco casos de recirculação dos gases de saída, do processo de sinterização, visando, sempre uma operação estável do processo. Os resultados de simulação indicam alargamento da frente de combustão com a recirculação dos gases de saída e a possibilidade da redução do consumo do combustível sólido. Como resultado, houve aumento da fração de cálcio-silicatos, proporcionando melhoria da redutibilidade do sínter, além da redução da emissão de CO2 e PCDD/Fs na máquina de sínter.

Aug 1, 2018

By Valdeci Paula Alvarenga, Sergio Luiz Costa, Itavahn Alves da Silva, Filipe Bueno Carvalho, Varadarajan Seshadri, Carlos Antonio da Silva

Use of fluorspar in steel refining operations is one of the environmental concerns and as such reduced consumption of this material or substitution of the same is one of the objectives. Industrial runs were carried out at Aperam Steel making convertor unit (Timóteo, MG, Brazil) using recycled/briquetted slag for partial or complete substitution of fluorspar. Samples were collected from the metal bath and slag after oxygen blowing to assess dephosphorization with several combinations of recycled/briquetted slag and fluorspar. The results showed that partial substitution of fluorspar by BOF slag briquettes did not affect the efficiency of dephosphorization. In general average Phosphorus content was reduced to 0.010% in the case of partial substitution compared to 0.016% in the regular refining procedure with no substitution. This replacement also resulted in 40% reduction of the fluorspar consumption in the converter

Jan 1, 2015

By Sean Paterson

The purpose of this paper is to demonstrate a method of delaying and loading a shot. Since entering the construction industry, I have learned that cover is needed on a lot of blasts. When in close having to cover shots was new to me and it seemed time consuming and wastefull. Until I really needed it and didn’t have it. So What To Do??? Remember that safety comes first, if you have concerns cover it. Even if you have to sit on your shot all night to wait for cover. This method is not a replacement for cover, but it will help keep your rock down. Do not bet your life, others lives or your career on it.

Jan 1, 2001

By J W. Muir, N Bedford

Hong Kong is one of the most rapidly developing cities in the world. With constant population growth and limited opportunities for space, the development of a fast and effective underground public transportation network is essential. Hong Kong’s Mass Transit Railway (MTR) Corporation is currently undertaking several large underground expansions to its existing network. Much of the excavation will be carried out using the drill and blast excavation method.Drill and blast excavation is common in Hong Kong and with the continued development of underground infrastructure the use of the drill and blast excavation method will increase. Although an effective method of excavation, the blasting vibrations caused during construction can have an adverse impact on surrounding structures and impose disruption on the local community.In order to minimise the risks associated with blasting vibrations, and to demonstrate that the impact on local stakeholders will remain within acceptable limits, it is generally necessary for a contractor to submit a blasting assessment report for approval by government authorities before blasting may commence.Continued increases in population density will force more infrastructure to be constructed underground. Tunnels and caverns are increasingly excavated in closer proximity to critical sensitive receivers. This leads to greater potential impacts on the community, tightening constraints on contractors and a higher level of confidence required for approval authorities. Finding a balance between the needs of the community and rising construction costs becomes more challenging.This paper presents a case study on how the blasting assessment report process has been successfully implemented for a major MTR project situated in a densely developed area of Hong Kong. It describes several methods of assessing blasting vibration impacts, innovative uses of blasting for excavation and the mitigation measures employed to provide the best outcome for all project stakeholders.CITATION:Bedford, N and Muir, J W, 2014. Blasting vibration assessment and innovative blasting methods in high-density urban environments, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 9–20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Yongzhong Xiao, Tiejun Chun, Jian Pan, Zhen He, Deqing Zhu

"In this paper, the reduction kinetics of low grade hematite ore was calculated. Mineralogy shows that the ROM (run of mine) ore is of low grade hematite ore type, assaying 27.2 wt% Fetotal and with main valuable minerals of hematite. The reduction kinetics shows that the reduction reaction rates of pellets with additive and without additive are all controlled by diffusion through the product layer. The calculated apparent activation energy of pellets with 12 wt% complex additive is 8.55 KJ/mol, dropping 62.23% compared to that of pellets without additive.IntroductionWith the rapid development of iron and steel industry in China, there has been a soaring demand for iron ores in the past decade. The imports of iron ores have increased from 148 million ton in 2003 to 620 million ton in 2010[1]. Therefore, large quantities of low grade iron resources are necessary to utilize in China at the moment. During the past years, extensive research has been carried out on the low grade hematite ores [2-6], such as reverse floatation, gravity separation, high-gradient magnetic separation and direct reduction-magnetic separation. Direct reduction-magnetic separation is an innovation way to treat the low grade hematite [7]. However, the research of reduction kinetics of low grade hematite is few. Some research about the reduction kinetics of reducing iron oxides by CO was studied [8]. The results indicated that the apparent activation energy is 8.0-28 KJ/mol when the reducing reaction is controlled by internal diffusion. The apparent activation energy is 50-75 KJ/mol when the reducing reaction is controlled by chemical reaction. In this paper, the reduction kinetics of pellets was also been studied."

Jan 1, 2012

By Rebecca Boakye, Zohreh Kazemi Motlagh, Virginia T. McLemore

The most significant uranium (U) deposits in New Mexico are sandstone-hosted deposits in the Morrison Formation (Westwater Canyon Member), where >169,500 short tons of U3O8 were produced from 1950 to 2002. In addition, >9076 pounds of vanadium (V, a critical mineral) and some molybdenum (Mo) were produced from these deposits. These and other U deposits (limestone-hosted, U-veins) in New Mexico also contain critical minerals. Critical minerals are mineral resources that are essential to our economy and whose supply may be disrupted; many critical minerals are 100% imported into the U.S. Some sandstonehosted, limestone-hosted, and U-vein deposits are elevated in heavy rare earth elements. One sandstone-hosted sample contained 0.3 ppm Re (critical mineral), 659 ppm Se and 408 ppm Mo. The arsenide five-element vein deposits in the Black Hawk district are mineralogically and texturally complex, low- to moderate-temperature, hydrothermal, structurally-controlled, Ag-Co-Ni-Bi-As bearing carbonate vein systems with local minor elements. Mineralized samples from Black Hawk contain up to 9970 ppm Ag, 8540 ppm As, 5690 ppm Co, 72,400 ppm Ni, 57 ppm Bi, 165 ppm Sb, and 32,600 ppm U.

Feb 22, 2026

By Matthew Hirsch, Jason Connot, Nathan Rouse, Srivatsan Jayaraman, Akash Adhikari, Brent Meins, Purushotham Tukkaraja

The Deep Underground Neutrino Experiment (DUNE) is a world-class particle physics research project currently being constructed 4,850 ft, 1,478 m underground at the Sanford Underground Research Facility (SURF), former site of the historic Homestake Gold Mine in Lead, SD. Construction for the project involves drill and blast excavation of 800,000 tons of rock to house neutrino detecting cryostats adjacent to on-going particle research and sensitive lab areas. To protect nearby labs during the planned 4 years of blasting operations, project specs required installation of six steel, heavily reinforced blast doors designed to withstand 20 psi blast loads. This research aimed to quantify the pressure reduction across the blast doors and more accurately model underground blast wave propagation. 827 blasts to date have been monitored at eight locations on the 4850 level of SURF with some locations behind blast doors and some in front. Additionally, pressure measurements directly in front of and behind one blast door were taken during 94 blasts.

Feb 6, 2023

By R. V. Higgins

Tarner (1),3/ Muskat (2), and Schilthuis (1) have presented methods of calculating oil recovery by the expansion of dissolved gas with and without return of gas to the reservoir. Although electronic computers have eliminated the tedious and time-consuming calculations (4) required by each of these methods, many petroleum engineers do not have access to electronic computers. For these engineers a short method is presented that uses the Tarner method as a base. Moreover, for engineers who have access to computers and have not as yet prepared a program, the short Tamer method requires less computer time than the long iterative methods. In the proposed short method, no plotting of the calculated data is required to determine a point of intersection described in the original Tarner presentation, as only one calculation is needed to determine the value sought, or two calculations if greater accuracy is desired.

Jan 1, 1960

By J. B. Zadra, J. M. Gomes, Don H. Baker

Electrolytic deposition at 1,000 ° C in an electrolyte essentially consisting of 7 parts sodium pyrophosphate , 2 parts sodium chloride , and 1 part sodium tetraborate yielded tungsten of 99.9 percent purity . Scheelite concentrates containing 25 to 73 percent WO, and varying quantities of iron , lime , and silica were used as feed materials for the electrolysis . The metal contained less than 0.01 weight - percent each of iron , calcium , silicon , aluminum , carbon , and oxygen . Modification of the electrolyte permitted deposition of equal - quality metal from scheelite concentrates containing higher quantities of iron , calcium , and silica . The electrolytic separation of molybdenum and tungsten was accomplished by minor variations in the operating procedures .

Jan 1, 1964

By S Hawker, M Gibbs, A Craven

Current climate change projections suggest both an increase in the intensity of significant rainfall events and an increase in the variability of rainfall in some regions of Australia. It is necessary for mine site owners and operators to understand the effects that this potential shift in climate may have on their operations. The ability to maintain compliance with discharge regulations and operational security for those sites that rely on surface water run-off harvesting may be negatively impacted if some current climate change projections are realised. Although current regulations require the preparation of water management plans, these are generally developed using historical climate records for the site in question and as such do not give any indication of a siteÆs resilience to the influences of climate change.This study compares design and operational considerations for a case study mine site using historical rainfall records and modified records representing climate change projections. The future climate models are invariably broad scale and are limited in their capacity to be downscaled to a reasonable resolution for developing a site water balance. Instead the local historical data set has been modified to concentrate precipitation to peak periods and propagated through the model. The study looks at the siteÆs response to the potential changes in climate.It is shown that if current climate change projections are realised, this will have a significant effect on both the necessary size of designed surface water infrastructure and operational considerations on-site. A discussion is presented on the potential risks that climate change presents to mine sites and the range of options that could be considered to mitigate these risks. Depending on a number of factors, including location and risk profile of the owner/operator, resilience to climate change can be addressed as either a capital or operational expenditure (CAPEX/OPEX).CITATION:Craven, A, Hawker, S and Gibbs, M, 2013. Site water balance response to variable climatic conditions, in Proceedings Water in Mining 2013 , pp 211-216 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By N. Schmalbein, L. von Ketelhodt, L. Kotelo

"The mining industry continues to remain challenged. Lower commodity prices, increasing labor costs and more importantly diminishing reserves are amongst some of the primary factors contributing to the difficulties faced. Ore sorting technologies have demonstrated their potential to improve the downstream beneficiation performance. The general processing route sees all primary crushed material milled for liberation and then processed in accordance with characteristics of the gold therein, i.e.: refractory golds would require direct leaching or oxidation whilst free gold would follow the conventional cyanidation process, after gravity concentration. Ore dilution increases the associated operating costs within each stage of this process. The opportunity to process the same throughput at a higher grade can only be achieved through pre-concentration. Sensor based sorting has been examined on numerous occasions by various gold producers. Test work carried out on different bulk low grade gold ores has shown the successful applicability of ore sorting to remove waste, whilst maintaining high recovery rates of gold. The results of a combined XRT/Laser sensor sorter have shown grade improvements of over 300% from feed grades of 0,25g/t to 1,15g/t at gold recoveries of 66% and waste ejection rates of 85%. This paper presents some of the results from the work undertaken by STEINERT with respect to gold sulphide ore sorting and presents a modelled financial scenario, which can enable a company to target and reclaim low grade ores.INTRODUCTION The mining and minerals processing industry presents with many different challenges including, volatile commodity prices, increasing labor costs and more importantly diminishing reserves. Conventional processing routes will continue to play a crucial role in the beneficiation process, however innovative methods of reducing operating costs and optimizing on the overall circuit performance is where technologies such as sensor based sorting come into the fore. Sensor based sorting as a dry mechanical process not only reduces water consumption by eliminating unnecessary waste but also reduces the requirements for reagents in the downstream processes. Sensor based sorting under dry conditions presents a highly efficient alternative to wet pre-concentration methods such as dense medium separation (DMS)."

Jan 1, 2017

By A. A. Berk

The Bureau of Mines devised a test nipple for the field study of corrosion in the condensate-return lines of Federal heating plants. Corrosion surveys, made with this device, showed that the deterioration of the piping was caused principally by carbonic acid in the steam condensate. Corrosion problems were brought under control when the carbonic acid concentration in the condensate was decreased. In many instances, this was effected by decreasing the total carbon dioxide content of the feedwater; in others, the condensate acidity was neutralized with volatile, alkaline chemicals. Filming treatment with octadecylamine, reported successful in controlling return-line corrosion in industry, was much less effective in Federal area-heating plants. Laboratory study by the Bureau disclosed that octadecylamine is unstable in heating systems. Analytical methods were developed for this chemical and its degradation products in heating-plant condensate. Field surveys, in using these methods, confirmed the instability of the filming material. Laboratory tests showed that the degradation products are not useful film formers. Since filming treatment has little effect on condensate corrosivity, the piping was corroded where it was not coated by the treatment chemical.

Jan 1, 1962