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By Charles Will Wright

This paper will be of interest to those who are actually developing a mineral prospect or planning to do so, as well as to investors who are considering the problem of financing the development of the prospect, so that they may know what the risks are and what capital expenditures are necessary before a prospect may become a mine. The term "prospect" used broadly, as it is in this paper, is defined as any property that has a mineral showing of sufficient interest to warrant development, irrespective of prior work, Such previous exploration, however, may be extensive and consist of several tunnels or adits connected by raises, or of shafts with several levels. There may also be a small mining and milling plant on the prospect which, because of the lack of capital for development or the lack of markets for the products, is now idle. Such prospects may warrant further capital investment for development work or for a mine plant to raise to the stage of profitable production.

Jan 1, 1935

APPLICATIONS for loan contracts for the exploration, development and mining of strategic and critical metals and minerals are now being accepted by the Department of the Interior. The RFC is authorized and directed by Executive Order 10161 to make such loans but the Secretary of the Interior must pass on the necessity for the loan. Applications should be addressed to James Boyd, acting deputy administrator, Defense Minerals Administration, Department of the Interior, Washington, D.C. rather than to the Field Offices of the Bureau of Mines as was first planned. Application forms are not yet available but it has been learned that data accompanying the application should include the known quantity and grade of reserves, the anticipated rate of production, the equipment, supplies, and man power required for the additional production, etc.

Jan 12, 1950

By J. Kempken

Driven by customers, especially from the automotive sector, the supply of 100% prime quality has become essential. Furthermore the implication of quality costs and the yield of first class products define the steel companies' profitability and overall success significantly. The SMS group together with its subsidiary MET/Con has developed a comprehensive solution to assess the product quality over the production and processing chain. Process and production parameters originating from various data sources of the process automation are examined on their impact of quality related characteristics.Expert know how and comprehensive operational experience is translated into a quality guideline and a regulation framework as the sensitive core of the PQA solution.Once implemented, the system identifies immediately steel grade specific, deviations from ideal standard and proposes corrective actions including a final evaluation for each product at each processing step.The X-Pact® PQA (Product Quality Assessment) system is a substantial tool for root cause quality analysis and provides the required support to the production team. It will become an integral part of the corporate quality management system.

Aug 17, 2017

By F. C. Stanford

THE work of an engineer is to direct natural forces so that they bring about the results that he wishes to secure. Heretofore he has concerned himself chiefly with physical forces and inanimate objects, until he has secured a truly marvelous degree of control over them. The great problem of the present age is to secure a like degree of knowledge and control of the human factor. Progress has already been made along this line, but, it is only a beginning. Wilhelm Ostwald says that scientific knowledge enables a man to be a true prophet; but it must be remembered that a good many people do not seem to be able to maintain a high average in prophecy. In short, the average of knowledge is not equal to the average needs of the present time, but continually fails to keep pace with it. It has been aptly said that the really essential need of the period is for more brains; if we only had sufficient knowledge and sagacity we could not only solve all difficulties, but prevent them from arising. This generalization holds good for an industrial organization. The most vital need of the management is for more brains. The logical course for an engineer in charge of an industrial organization is, therefore, to direct whatever forces may be at his command toward the development, training, and guiding of all the brains in his organization. This is easier said than clone, for it involves the carrying on toward two objectives, the maximum of productive work, and the development of the individuals who perform it. This is essentially like the rebuilding and enlarging of a plant, keeping it in full operation the while. On the other hand, if the aim is merely for maximum production from an organization, without offering opportunity for development, the final outcome will necessarily be like that f a plant that is driven at full capacity without stopping for repairs or improvements; it eventually becomes so run down that either a complete rebuilding is necessary or else it has to be abandoned.

Jan 2, 1918

By A Mackay

As a result of the explosion in the 512 panel at the Moura No 2 mine in 1994 the role of the ventilation officer (VO) to submit sealing plans (on behalf of the operator/underground mine manager) has become one of the key duties of the VO of an underground coal mine in Australia. The intent of a sealing plan is to document the controls used to manage the build up of flammable concentrations of gases, and for these controls to be reviewed by the industry regulators. These sealing plans have brought a large amount of focus onto the sealing process and served the industry well. The legislation does not define sealing, or when it begins, but throughout the industry typically sealing plans are submitted 30 days prior to the last seal being constructed. This practice appears to have originated from the Moura 512 panel being a standing bord and pillar panel and where the explosive gas mixture could only occur after it was sealed. However, since the Moura disaster the industry has become dominated by goafing style longwall mining. Goafing panels differ from standing bord and pillar panels in that they typically have an unventilated goaf that can potentially contain an explosive mixture from start-up. This was recently highlighted by the explosion and fire on Longwall No 1 Tailgate at the Blakefield South Mine in 2011. The author ponders whether the industry should revisit sealing plans to focus on the core hazard and define that sealing begins when flammable concentrations of gases are created. Although defining when mine sealing begins is the key outcome of this paper, the main point is that VOs and industry regulators need to clearly understand what can occur in the atmosphere of underground coal mines. CITATION:Mackay, A, 2013. A case for change - Defining mine sealing and understanding flammable mixtures during sealing, in Proceedings The Australian Mine Ventilation Conference , pp 307-310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By David S. Yang, Osamu Taki

The innovative Soil-Cement Mixing Wall Technique, developed independently in Japan, consists of mixing in-place soils with cement grout using multi-axis augers and mixing paddles to construct overlapping soil-cement columns. The applications of overlapped soil-cement columns include cutoff walls for groundwater control and structural diaphragm walls for excavation support. The special features of this technique include water tightness, versatile strength design, and efficient installation in subsurface materials varying from clayey soils to cobbles or soft rocks. Through the introduction of two recent subway projects in Japan, this paper presents the design parameters, construction procedure, quality control and performance of soil-cement wall for excavation support and groundwater control.

Jan 1, 1989

By D. Cantali

This paper will be presented in two parts. The first part will present the latest advancements in pile installation techniques using state-of-the-art press-in piling technology by Giken. By pressing in sheet piles and large modulus contiguous steel tube pile walls – as opposed to the more traditional installation methods using percussive hammers or vibrators – retaining structures can be constructed effectively noise and vibration free. For over water and coastal projects with limited access, this provides significant environmental benefits in the form of minimising the construction foot print and the impact to surrounding communities and the marine natural habitat. Typical noise and vibration data will also be presented. The second part of this paper will review the current manufacturing techniques for sheet piles and introduce innovative new materials used in the current piling market for embedded sheet pile walls. Materials include long service life non – ferrous materials such as new age plastics and fibre reinforced polymer piles. Their excellent long term performance and durability make them an effective solution in the marine environment. For steel piles, a number of steel grades with reduced corrosion characteristics will also be discussed including a newly developed steel to combat corrossion in the low water zone, an area often exhibiting the highest moments in a retaining wall. A number of project case studies will also be presented to reinforce their relevance in today’s changing construction landscape.

Nov 1, 2022

After many years of studying the rock mass gravitational flow phenomenon, it is well known that moisture conditions may change the mechanical properties of the caved and broken material, causing different problems at drawpoints. One specific problem, perhaps one of the most unpredictable and uncontrollable, is that of mudflows (also known as mud rushes). The aim of this paper is to show how to establish optimal extraction rates at a drawpoint in order to avoid the closure of that drawpoint due to the high risk associated with having high-technology automated loaders working in the production level of panel cave and block cave mines prone to mud flow events. This optimisation should take into consideration critical restrictions related to mine planning, such as the need to reach the planned production. It is also important to consider the correct design of surface (in the subsidence zone) and underground drainage systems to prevent groundwater or rainwater entering muck piles, filled stopes, galleries or open cuts. With these considerations, and keeping in mind other factors that should be included in a sensitivity analysis of variables, it is possible to find a correlation between the percentage of extraction from a drawpoint and the possibility of occurrence of a mudflow. Finally, this paper proposes different draw strategy techniques in order to mitigate potential mudflow issues on a caving production level.

Sep 26, 2011

By L. K. Smith

Flotation work conducted by CSIRO on both single minerals and high-arsenic copper ores from a number of sources, has shown it is possible to produce separate low-arsenic copper concentrates and high-arsenic copper concentrates from high-arsenic copper ores. The procedure involves controlled separations at high or low pulp potential regions exploiting subtle differences in the flotation behavior of the arsenic-bearing and non-arsenic-bearing copper minerals. An overview of several case studies investigating the applicability of the controlled potential flotation approach to the separation of copper and arsenic from sulfide copper ores is presented. It highlights the variables which influence the efficiency of the separation which include mineralogy, liberation and reagent selection. The procedure can produce a saleable low-arsenic copper concentrate, which can be directly smelted without penalty, and a high-arsenic low copper concentrate, which will require further processing. Keywords: flotation, copper, arsenic, controlled-potential flotation

Sep 1, 2012

By White A. H, Vihena M. T M B

Presently, orebody modelling consists basically of fitting a mathematical model to represent spatially a certain geological variable, generally grade. An orebody model is constructed from a set of sample data obtained from various locations in the orebody, thus it is only one form of representation of the true phenomena. Checking the compatibility of the data with the modelling procedure is the most important factor when assessing confidence in the orebody model. The level of confidence in the model will depend on the adequacy of the data set and the validity of the basic assumption required by the modelling method. Fractal geometry is one way of modelling the spatial distribution of a geological variable in an orebody geometry. Fractals can be used to interpolate the Z(x) geological variable at unsampled sites. The concepts of self similarity and self affinity that form the basic assumption of fractal geometry theory which areinvestigated. The population distribution of the geological variable in question must be examined to determine the appropriateness of both fractal geometry and geostatistical modelling methods. The selection of the most appropriate method depends on the available data. A researcher or a practitioner needs to understand the strengths and limitations of the various modelling methods before choosing the most appropriate method. This study investigates the fractal properties of grade distribution using the variogram and some proposed variations as techniques to measure the fractalness. The aim is to assess applicability of fractal geometry theory to modelling ore grade distribution in a deposit. A comparison of the results demonstrates the methods which better capture the spatial behaviour of the variable under study.

Jan 1, 1995

By Kevin Gunesch

In the current difficult financial markets, only the best projects will advance to the next phases of development due to limited funding. Projects are consistently being evaluated by their initial Capital Expenditure (CapEx), Net Present Value (NPV), and Internal Rate of Return (IRR). Optimizing these parameters is the best way to gain market interest. Global Resource Engineering LTD (GRE) completed an optimization study for a silver-lead-zinc project in Peru. In this sense, the objective of the study was to minimize the project initial Capital Expenditure while maximizing the Net Present Value and Internal Rate of Return. GRE accomplished this goal by completing a series of tradeoff studies for the project and combining them through the use of a multi-scenario deterministic model to find the most economic scenario.

Oct 21, 2015

By A. Patton, F. N. Speller

The use of roll scale in the Bessemer process dates back, to the best of our knowledge, at least 20 years. It was first used by the Ohio Steel Go., Youngstown, Ohio (now the Ohio Works of the Carnegie Steel Co.) under the direction of Sam McDonald, Superintendent of the Bessemer Department at these works. Two 10-ton vessels and one blowing engine capable of blowing one heat at a time were employed. The object of using the scale was to shorten the length of the blow, or in other words, to increase the production with the same equipment. Various means were tried out for introducing the roll scale into the bath of molten iron: It was shoveled into the vessel before the heat was charged, so that the metal would flow over the scale; it was shoveled into the bath after the vessel was turned up; it was dumped into the empty iron ladle by the wheelbarrow-load, and at times was dumped on top of the molten metal in the iron ladle. But the practice of introducing the scale into the iron ladle had to be abandoned on account of danger from explosions and of skulling the ladles. It was soon learned that the proper place to charge the scale was in the empty vessel, so that when the molten iron was poured into the vessel it flowed over the scale, causing a considerabIe reaction to take place before the heat was turned up. Eventually, cylindrical chutes similar to those now in use were installed. Into these chutes the scale is dumped and carried into the empty vessel. Before this convenient means of introducing the scale was adopted, the Ohio Works had satisfactorily demonstrated that roll scale would increase production, by blowing 107 heats in one 12-hr. turn (1,087 tons) with one blowing engine, blowing one heat at a time; whereas, prior to the use of scale, the best practice at these works was about 80 heats under the same conditions. In using roll scale and other oxides of iron to facilitate and control the refining of pig iron in the converter, the Bessemer plant has borrowed one of the most active agencies used in the open-hearth process with, as would be expected, much the same results. The effect of such additions to the Bessemer charge may be discussed as to the influence of this practice on quality, production and cost.

Jan 1, 1917

By Oliver Bowles

"Rhodesian asbestos is of high quality and is much in demand by American consumers. Production in Rhodesia was first reported in 1909. The production for this and each succeeding year is shown in the following table:The serious curtailment in production for the years 1912 and 1913 was occasioned by transportation difficulties. In 1914 a railway was projected to Victoria and thereafter production increased greatly. Up to 1916 asbestos was obtained,from the Victoria district only, but thereafter the Bulwayo district became an important,producer with minor quantities from Gwelo.In the Bulawayo district the productive area is about 2 1/2 miles long, with Shebanie mine at the north-west end, the Nil Desperandum at the south end, and the Birthday claims between them."

Oct 1, 1920

By J. J. Demeter

As part of its work on converting coal to fluid fuels, the Federal Bureau of Mines has been studying the synthesis of liquid fuels from carbon monoxide and hydrogen by Fischer-Tropsch synthesis. A fluidized bed of nitrided, fused-iron catalyst has been operated successfully to produce high yields of oxygenated compounds. Trouble-free operation continued for over 800 hours, and the test was terminated voluntarily. About 85 percent of the fresh feed was converted when the unit was operated at a space velocity of 500 hr.-1, a 12:1 recycle-to-fresh-feed-gas ratio, a 300-p. s. i. g. pressure, and a temperature of 252° C. When operating at a fresh-feed-gas space velocity of 1,000 hr.-l and a 9:1 ratio of recycle to fresh gas, conversion of fresh feed was 68 percent, and the product yield was 235.9 grams per cubic meter of synthesis gas converted. The oxygenate and C5 and heavier hydrocarbon yield was 110.6 grams per cubic meter of gas converted, 83 percent of this was oxygenates. The atom ratio of N:Fe of the catalyst, initially 0.455, decreased to 0.288 by the end of the 800-hour experiment. Nevertheless, the yield of oxygenated compounds per cubic meter of H2 + CO converted at the end of the run was approximately the same as that obtained 500 hours earlier with identical operating conditions. X-ray analysis of the discharged catalyst indicated that only ?-iron carbonitride was present. Sieve analysis of the discharged catalyst indicated that only 2 percent of fines was produced during the reduction, nitriding, and synthesis.

Jan 1, 1959

By C. H. Pitt

A jet slurry apparatus has been constructed to test corrosive/erosive wear properties of grinding ball metal. Plain high carbon steel heat treated to a hardness of about 60 RC was used. Slurries of quartz and chalcopyrite ore concentrate were used as the jetting media. Weight loss due to pure corrosion was determined by the linear polarization technique and weight loss due to pure erosion was determined by jetting while cathodically protecting the sample. By comparing the total weight loss with the sum of the weight losses from pure corrosion and pure errosion it was found that there was a synergistic effect between corrosion and erosive wear. Erosive wear rates are given as a function of pH and mineral type.

Jan 1, 1984

These proceedings consist of papers presented at a Bureau of Mines Technology Transfer Seminar in September 1981 for the purpose of disseminating recent advances in mining technology in the area of premining research. The introduction and descriptive papers discuss techniques and instrumentation used in premining research for metal and nonmetal mining and shaft design and borehole control for premine planning.

Jan 1, 1982

By Sevket Acar, Tim Acton

"Zarafshan/Newmont is a 50/25/25 joint venture between Newmont Gold and the State Committee for Geology and Mineral Resources, and Navoi Mining and Metallurgical Combinat, two entities of the Republic of Uzbekistan. The Zarafshan/Newmont joint venture consists of a heap leaching operation which will process 220 million metric tonnes of existing low-grade oxide ore stockpiles (averaging 0.036 oz Au/t) from the Muruntau mine. Net recovery over the 17-year life of the project is expected to be 4.8 million ounces of gold.The plant construction started in October 1993 and operations commenced on May 25, 1995. The crushing plant consists of four stages of crushing and screening to produce a 95% passing 3.35 mm product, followed by heap leaching and gold recovery by the Merrill-Crowe process. The dore metal is refined at the Muruntau refinery. All gold produced by the joint venture is sold on the world market. IntroductionThe Muruntau mine and nearby town of Zarafshan are located in the center of the Kyzylkum desert, 250 miles west of Tashkent, capital of Uzbekistan. Following a mining conference in Moscow in 1990, a Newmont geologist was among the first team of westerners to visit the Muruntau Mine, the second largest gold producer in the former Soviet Union. At Muruntau, they found 220 million tonnes of low grade gold ore that had been stockpiled during the previous 25 years. In February, 1992, six months after Uzbekistan's independence, Newmont signed a 50/50 joint venture agreement with the Uzbek government to use heap leach technology to process the ore. The feasibility study was completed in November of 1992. Plant construction started in October, 1993 and operations commenced on May 25, 1995.Newmont Metallurgical Services performed metallurgical studies to obtain heap leach process design criteria parameters. The initial metallurgical study on 20 grab samples is the subject of this paper."

Jan 1, 1997

By C. Bryce

Rhenium is primarily recovered as a byproduct from molybdenum roasting circuits. However, rhenium is also present in copper heap leach solutions at very low concentrations, and this represents a potential new rhenium source. Freeport-McMoRan (FCX) has developed a new process using carbon adsorption followed by ion exchange or solvent extraction to concentrate rhenium from less than 1 ppm to 15 g/L. The product is compatible as a feed to an existing rhenium processing plant. A pilot plant operated at Freeport-McMoRan?s Sierrita Mine has demonstrated the technical and financial feasibility of this new process. Copper heap leaching dissolves more than just copper from the copper ore. Several metals can be identified in leach solutions at concentrations of financial interest, rhenium in particular. Rhenium spot prices ranged from a yearly average of $1,070/kg ($483/lb) in 2005 (Magyar, 2008) to $10,400/kg ($4,706/lb) in 2008 (Polyak, 2013). The spot price in September 2013 was approximately $3,000/kg ($1,357/lb) of rhenium (Metal Bulletin, 2013). Several facilities at Freeport-McMoRan have very low rhenium concentrations in their copper leach solutions, ranging from 0.1 to 0.7 mg/L. The large quantity of solution available, if coupled with an attractive rhenium price, means that the rhenium contained in leach solutions may represent a significant value if a method of extraction could be developed. Testing has confirmed that rhenium adsorbs onto activated carbon much more selectively than other metals in the pregnant leach solution (PLS). A 100-gpm pilot plant was constructed to verify the lab-scale results on a larger basis and establish operating parameters for a full-scale operation. This report summarizes the initial technology development and pilot plant operation.

By M. V. Rowley, D. D. Warkentin

With high commodity prices, tightening operating budgets and increasing disposal costs, there is an increasing interest in processing municipal waste streams, such as the ash derived from combustion processes. This paper describes laboratory development work for a process to recover metal values from the finer fractions of these wastes. The work was initially aimed at recovery of copper and the removal of lead and other heavy metals from the ash residue, but results showed gold and silver recovery to be an important objective as well. The process uses gravity and flotation as the principal separation steps, with gold recovery occurring mainly in the flotation stage. The particle size range and chemistry of the ash presented numerous challenges to developing a suitable flotation method, but an effective flowsheet was developed by separating the ash into a fine fraction and a separate slime fraction, each with a unique flotation strategy. Specialized conditioning stages and careful reagent selection have resulted in effective gold and silver recovery from a range of ash types and sources. The work has resulted in a patent being issued for a process based on this novel approach to the treatment of combustion wastes.

Jan 1, 2017

By Tsisana Gagnidze

A processing of technogenous wastes, which involve a gold-containing sulphide minerals, is a potential source to supplement the gold reserves. Hence, searching of ecologically safe and economically reasonable methods for processing of gold-containing technogenous wastes is a topical problem. To increase a parameters of gold extraction and to simplify a technology of the processing of above-mentioned wastes of sulphide minerals, an investigations have been carried out in the direction of the use of the method of electrochemical leaching without any preliminary processing of the mineral. It was established experimentally that an introduction of nitrogen containing organic additive into chloride solution favours to reduce a Red/Ox potential of the solution from 0,8÷1,2 V to 0,35÷0,5V, which permits to conduct the process of direct electrochemical leaching at ?soft? oxidation regimes at temperatures 20-300C C without an environmental contamination by molecular chlorine and with a high degree of a gold extraction up to 80-90%.

Jan 1, 2008