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By William Rachunis

This publication describes the construction of 43.64 miles of underground tunnel to be used as an aqueduct, known as the West Delaware aqueduct. In the past, the accident history of tunnel operations has not been favorable, the "rule of thumb" being a death for each mile of progress, according to the meager accident statistics available for the tunnel-driving industry. The accident experience at this project and the use of modern equipment established safety and progress records that were accepted by tunnel people as a record at the time. The city of New York comprises 5 boroughs, with a total population of approximately 8 million people, and uses about 1,210 million gallons of water each day. The water supply for the city is the responsibility of the New York City Board of Water Supply. This organization has constructed an extensive aqueduct system, the Delaware aqueduct, to convey water to the city from the distant mountain and river sources in the Catskill Mountains in the Southern Tier areas of New York State (figs. 1 and 2).

Jan 1, 1962

By Tyler Acorn, Paul Worsey, Nathan Rouse

The effect of the hole diameter on vibration attenuation has not been incorporated in most vibration models in the blasting industry. In current vibration models, the charge weight and the distance from the blast are the two primary variables that are addressed. Charge weight is a function of explosive density, charge length, and charge diameter. This geometry-weight can complicate the isolation of the charge diameter variable.

Jan 1, 2013

By Mark Viduetsky, Dmitry Tropnikov, Victor Maltsev, Victor Sokolov, Alexander Purgin, Andrey Panshin, Alexander Bondarev, Pavel Kozlov, Igor Garifulin

"CFM pneumatic flotation machines were developed by the Institute of Materials Science and Metallurgy, UrFU, and designed to concentrate a wide range of ores and man-made materials. A key principle of work is pulp preparation for flotation owing to its saturation with finely dispersed air bubbles in ejectors. CFM plants, their advantages over domestic and foreign prototypes are described. CFM pneumatic machine commercialization resulted in: - machines demonstrated high floatation efficiency for concentration of rebellious pyrrhotite-bearing copper and zink by simultaneous floatation of copper and zinc minerals and depressing pyrrhotite. CFM- 1400M introduction allowed simplifying and optimizing the flow chart and increase extraction of copper - by 5.4%, zinc - by 9.5% and improve the quality of copper (3% Cu) and zinc (1.5% Zn) concentrates. - due to copper pyrite concentration by using CFM 1400M overall copper recovery was increased by 1.5 %, and the content of copper in concentrates - by1%. According to the results of pilot runs, the use of CFM flotation for zinc cakes concentration strongly intensifies the process of cleaning water-soluble metal compounds and, thereby, increases the efficiency of flotation concentration and subsequent milling. CFM machines showed higher specific capacity (three or four times higher) (both for feed material and froth product). Specifically, CFM froth product has higher content of useful elements (silver by 0.014 % abs. zinc by 0.31% abs.) and better extraction (silver by 6.08% abs., zinc by 0.31% abs., and sulfide sulfur by 13.7 %). Sulfide sulfur content of CFM product chamber as compared to mechanical flotation machines is two times lower (0.48 vs. 0.95 %)."

Jan 1, 2014

By E. N. Levchenko, K. V. Bulatov, G. I. Gazaleeva

"The article highlights the new procedure of choosing special methods of disintegration for very complicated rare ores. Especially, there is a complex approach to criteria of comparing different types of crashing machines. Criteria are as follows: degree of crashing, degree of grinding, degree of slime creation and the new creations criteria for selection. The procedure is tested on tantalium and zelestinium ore. A new methods was shown the preference impact crashing machine MD-7 for zelestinium ore. In product of crashing 0,050 mm size are 9.4 %, 0,005 mm size – 2.5 %.This is gut result, and show the best indexes of slime creation. The check of the proposed new methods was done when comparing the crushing of tantalium ores of the Otboynoe deposit in cone inertial and centrifugal impact crushers and roller press. A research was conducted different crashing machines under laboratory and semi-industrial conditions. Different operation modes of crushers were also checked. The comparison of the crushing selectivity criterion and degree of crashing showed that the centrifugal impact crusher (CC) and roller press (RP) has the lower indexes than the cone inertial crusher (CIC). Degrees of crashing for different crashing machines are:centrifugal impact crusher – 10.1;roller press – 10.8;cone inertial crusher – 14.2. The crusher CC the selection criterion is 0,632 units, RP – 0.730, where as for the crusher CIC – 0.848 units. The best crushing mode for the crusher CIC-300? is as follows: turning angle of debalance is 0°, peripheral speed of a cone rotation – 1420 r.p.m, specific energy consumption- 4.99 kW*t/t. Crusher CIC-300? is the best for tantalium ores of the Otboynoe deposit. The new methodic are verification.INTRODUCTION Rare metal concentration circuits are complex, energy-intensive, and costly. The reasons for this include the multimetal nature of the rare metal ores, their volatile material composition and low grade. That is why careful selection of ore preparation circuits is of great importance for minimizing the energy inputs and maximizing the liberation of the valuable minerals. Recent research (Khopunov, 2011, Gazaleeva, 2015) has demonstrated that the most efficient comminution processes available to the mineral processing industry are selective disintegration, crushing and grinding, allowing to liberate the mineral particles along the cleavage in the comminution process. These methods are indispensable for the processing of finely disseminated refractory ores prone to slime formation. Many rare metal ores found in Russia are of this type."

Jan 1, 2018

By Abhakumari

Effect of applied DC potentials on the bioleaching of a chalcopyrite concentrate in the presence of Acidithiobacillus ferrooxidans is discussed. Copper dissolution was the highest at an applied potential of +600mV (SCE), while all the dissolved copper got cathodically deposited at a negative potential of -600mV (SCE). Electrobioleaching at an applied potential of +600mV (SCE) was established at different pulp densities as a function of time. Effect of the magnitude of electrolytic currents on the activity and growth of bacterial cells was studied. Preadaptation of bacterial cells to the concentrate slurry and electrolytic growth conditions significantly enhanced copper dissolution. Electrochemical and biochemical mechanisms involved in electrobioleaching are illustrated with respect to oxidative dissolution and bio catalysis of anodic oxidation.

Sep 1, 2012

By Kathryn C. Sole

A novel solvent-extraction process for the refining of gold was recently commercialised, with the commissioning in May 1997 of a 24 t a-' refinery at Harmony Gold Mine in Virginia, South Africa. The MinataurTM Process (Mintek Alternative Technology for Au Refining) uses solvent-extraction technology to produce gold of 99.99% purity from the cathode sludge arising from a conventional carbon-in-pulp / electrowinning circuit. Implementation of this process introduces significant cost benefits compared with the conventional dore smelting / toll-refining route previously followed. This paper outlines the process, presents selected operating results obtained during the first few months of operation, and provides some details of the associated techno-economic advantages.

Jan 1, 1998

The past four years since the 2008 MINExpo have been a roller coaster ride for the mining industry, with highs and lows and everything in between. One of the natural consequences of this uncertainty has been a number of significant consolidations and mergers, and this trend has trickled down into the crushing industry. And while there have been some significant changes to this sector of the mining industry, many of the big players have weathered the storm. The following is a look at some of the mineral processing companies that will be at MINExpo. McLanahan Corp. McLanahan Corp. is an example of the changes in the sector. The crushing and grinding stalwart acquired Universal Engineering, expanding its traditional focus on soft mineral crushing to hard rock crushing. At MINExpo, it will be showing off three new pieces of equipment, the LabMill Crusher, the Rocker Tooth Crusher and the Recessed Filter Press.

Jan 1, 2012

By P. M. Dranchuk

"""PLANET EARTH seen from space appears as a fragile and limited life-supporting system in a vast emptiness. That such a view is, in fact, an accurate one is now more widely accepted than it was not long ago, before Earth's problems of over-population, overconsumption, limited resources and environmental degradation attained the limelight. The danger is that a government and public now deluged by doomsday prophecies and bemused by equally confident reiterations that technology will cure all may hesitate in coming to grips with the problem, in the hope that, given time, it will go away."" With these words, Preston Cloud begins a recent editorial, in Science(l), in which he presents a brief resume of some of the findings of the Committee on Resources and Man of the National Academy of Science-National Research Council(20.Their report, which is based on a two-year study by an extremely competent group and consists of some 250 pages of text, is even more far-reaching and sobering than the report on Energy Resources(3). It begins by quoting Sir Macfarlane Burnet as follows:""There are three imperatives: to reduce war to a minimum; to stabilize human population, and to pre-vent the progressive destruction of the earth's irreplaceable resources.(4)"

Jan 1, 1971

By G. W. Jones

The determination of the ignition temperature of diethyl ether and ethylene in air and omen which is described in this report was made primarily for comparison with similar determinations of other compounds in the same apparatus and using the see laboratory technique. The investigation was conducted at the Pittsburgh Experiment Station of the United States Bureau of Mines with the cooperation of Merck & Co., Inc.

Jan 1, 1935

By G. Davis

It is well known that the anticipated mineral price at the start of a prospective mineral project can have an overwhelming effect on a property's ex ante value. However, possible price movements throughout the life of a project can also have an impact on this value. This paper demonstrates how different potential price paths can affect project value. When considering commodity price projections for mine valuations, it is thus necessary to estimate not only the expected commodity price at the start of the project, but also the manner in which that price is likely to fluctuate throughout the project's life.

Jan 1, 1995

Results of the study of chloride ion concentration effect to osmium-187 sorption from wastewater of copper smelter with use of foreign anionites of different basicity and structure are presented in the work. It was found that the increase of chloride ion concentration in the wastewater helps to increase recovery of osmium using anionites regardless of their nature. The ways to intensify the process are proposed. The method for osmium elution from the anionites with potassium iodate solution was developed. It was shown that the method lets to recover up to 99% of osmium from the anionites. Recommendations for selection of eluents for better recovery of osmium from the anionites were elaborated. Keywords: wastewater, osmium, anionite, sorption, chloride ions, eluent, recovery

Sep 1, 2012

By B. K. Cantrell, K. L. Rubow

"Two source apportionment techniques have been applied by the U.S. Bureau of Mines to aerosol measurements in diesel-equipped underground noncoal mines. The first technique is based on size-selective sampling and the premise that the diesel exhaust fraction of the aerosol is predominately submicrometer in size while the mineral dust fraction of the aerosol is mostly supermicrometer in size. The second technique, chemical mass balance (CMB) modeling, was used to referee the analysis of diesel and mineral dust aerosol concentrations with the size selective method.The size-distribution data were modeled using a lognormal regression to parameterize the submicrometer and supermicrometer fractions of the sampled aerosol and to estimate the mineral and diesel contributions to each. Using this analysis, 97 ± 2 pct of the submicrometer aerosol mass was attributable to diesel exhaust aerosol.The CMB analysis, applied to both fractions of the respirable mi11e aerosol, yielded the amount contributed to each by the diesel and dust aerosol sources. On the basis of this analysis, 94± 10 pct of the submicrometer fraction was diesel exhaust aerosol. As much as 20 pct of the diesel aerosol, however, was found in the supermicrometer fraction, requiring a correction of the submicrometer fraction results to account for the missing diesel mass. More accurate measurements will require a carbon-specific analysis of the aerosol.INTRODUCTION Measurement of the contribution of diesel exhaust to respirable aerosol in mine environments has become increasingly important because of current concerns over the occupational health effects resulting from exposure to diesel emissions. In response to this, the U.S. Bureau of Mines is developing and evaluating new sampling methods for measuring diesel aerosol in underground mines. Two such techniques are being studied by the Bureau, size selective sampling and CMB modeling. These techniques use measurable physical or chemical characteristics of a mine aerosol sample to infer the amount of diesel particulate material contained in the sample."

Mar 1, 1992

By D. Chen

The experiment adopted magnetic separation-priority flotation (first to float copper,then float lead) combined technology to deal with a complex Cu,Pb ,Zn multi-metals ore which has high sulphur content, difficult to separate Cu, Pb ,Zn minerals from sulphur and separate Cu from Pb. Floatable pyrrhotite was separated through magnetic separation which could eliminate the adverse effect on the flotation followed up. And then adopting the priority flotation process to recover the Cu, Pb ,Zn from the magnetic tailings. In priority, flotation Cu, BP(a kind of ethionine ester collector ) and ethyl xanthogenate were used as the collector, LD-1 and sodium sulphite were used as the depressant.The depressants combined with humic acid sodium and lime were used for chalcopyrite ? pyrite separation to further improve the copper concentrate grade. Considering the raw ore that contain 0.32% copper, 0.54% lead and 25.54% sulfur. The copper concentrate grade is 23.61%. The lead content of copper concentrate is only 0.85% . The recovery of copper is 75.03%,and the lead concentrate grade is 54.58%, the copper content of lead concentrate is only 0.81% and the recovery of lead concentrate is 62.24%. The mineral processing indexes were excellent, finally realizing the high effective separation of Cu, Pb , Zn and pyrite. This technique provides a new approach to highly utilize complex copper-lead-zinc ore.

Sep 1, 2012

By A. I. Urvanzev, N. V. Shikhov

"In this paper, we present the study’s results of electrical separation processes on the basis of new separator designs, new technological solutions, and newly discovered effects. We considered the options of enrichment by magnet separation of magnetite and titanomagnetite ores, ores and products containing chromium and manganese, ores of non-ferrous and precious metals. During pneumo-electric separation of mixed iron ore of SMPC, 43.3% of the output of the concentrate with an iron content of 61.7% was obtained in one step, with extraction of 70.5%. The paper also presents the results of the finalization on the air-electric separator of the magnetic fraction when separating oxidized ores of MPPOO (mining and processing plant of oxidized ores) on the Jans polygrade magnetic separator. A concentrate was obtained with an iron content of 65.1% with the extraction of 95.0% and tails with an iron content of 13.0%. The possibility of obtaining low-silica concentrates from these ores with an iron content of 67.15 and a quartz of 2.88% is shown. Also, the results of tests on the enrichment of chromite ores on the firing-magnetic scheme with corona-electrostatic separation are considered. On the initial ore of the Don MPP (mining and processing plant), a concentrate with a content of 61.8% Cr2O3 was obtained with a quartz content of ~ 1.0%. The results of pneumo-electric separation with triboelectric charge of the separated particles are presented. The results of the tests indicate a principal possibility of enriching chromite ores without costly high-temperature roasting. Dry technology of enrichment of manganese ores with the use of electrical separation increases the quality of the oxidized concentrate to the first grade and raises the total extraction by 2 times. For the Chineya deposit of titanomagnetite ores with copper impurities, electroseparation operations were carried out on two samples with a Cu content of 1.93 and 3.75%, respectively. For a sample with a Cu content of 6.02%, a copper concentrate output of 24.42% was obtained with a Cu content of 23.82% and the extraction of 94.88%. The results of enrichment by electroseparation of gold-containing sulfide ores can have the practical importance. For ores of the Berezovskoye deposit, a pyritic concentrate containing 100 g / t of gold was obtained after two or three operations of IES (integrated energy systems)."

Jan 1, 2018

By A. An. Mushketov, A. Al. Mushketov, N. A. Sopina

"INTRIDUCTION At present, more and more metallized raw materials with a metallization degree of not less than 80% are used in the smelting of steel. The main quantity of this raw material is produced in furnaces of mine type. Advantages of this type of raw materials for metallurgical processing are low levels of harmful and slag-forming impurities and a high content of metallic iron. At the same time, the cost of smelting raw materials and obtaining high-quality steels are reduced. In addition to the undoubted merits of metallized raw materials, there are high requirements for the quality of iron concentrates, which are the starting material for metallization: the mass fraction of acidic oxides should not exceed 3%; The mass fraction of iron should not be less than 69%, mass fractions of harmful impurities (phosphorus, arsenic, sulfur, copper, etc.) should not exceed 0.02%. These requirements are dictated by the fact that the recovery of burned pellets is carried out by gas in a solid phase. In this case, the empty rock and harmful impurities from the metal are not separated and sent to the steelmaking unit, increasing the heat consumption for heating and worsening the quality of the steel. The combined production of high-quality concentrate and metallized raw materials requires a large capital outlay from the enterprise, which in the future can be compensated for by increased profit from the sale of more expensive marketable products. At present, in the territory of Russia and the CIS countries Lebedinsky mining-and-processing integrated works is the only enterprise that carries out the entire chain of operations for the production of metallized raw materials, starting with the production of high-quality magnetite concentrate with a mass fraction of iron of 69.5% and ending with the production of a metallized product in the form of hot briquetted gland. JSC «SSGPO» is the largest iron-processing enterprise in Kazakhstan, which processes about 40 million tons of ore per year and receives 16 million tons of concentrate per year with a mass fraction of iron 66.0-66.5%. The technological scheme existing at the concentrator of JSC ""SSGPO"" includes the crushing of the feed ore to the size of 20-0 mm; dry magnetic separation operation; three reduction stages to a fineness of 90-95% kl-0.071 mm; operation of desliming, wet magnetic separation and filtration of the concentrate. Dry magnetic separation of the feed ore makes it possible to remove from the process of 19.6% of the tailings with a mass fraction of the total iron 12.5%, of magnetite 2.2%. The first reduction stage is carried out in rod mills with the volume of 40 m3 to a size of -1.6 + 0.0 mm. The first stage of wet magnetic separation is carried out in counterflow magnetic separators PBM-P-150/200L. The magnetic product of the first stage of WMS is classified in hydrocyclones; sands enter the second reduction stage into central discharge ball mill 3600 × 5000. Runoff of mills enter on the second enrichment stage in counterflow magnetic separators PBM-P-150/200L. The magnetic product enters the classification of the second stage, forming a closed cycle. Mass fraction of the class -0.071 + 0 mm in classifications runoff of the second stage is 70-75%. The second stage classifications runoff is transported toWMS-III operation in semi-counter separators PBM-PP-120/300. The magnetic product of the third stage enters the classification of the third stage. Granular residue are transported to the reduction of the third stage into central discharge ball mill 3600 × 5000. The mill runoff enters the third stage of classification, forming a closed cycle. Classifications runoff of the third stage enters on deslimation. Deslimed product is sent for fine screening to the crasher «Derrick» 2SG48-60W-5STK with a cell size of 0.1 mm. Top size of crasher is sent to regrinding. Undersize with a mass fraction of the class -0.071 + 0 mm 90-95% is fed to the wet magnetic separation of WMS-"

Jan 1, 2018

By Sue Xue, Carl C. Nesbitt

A project was completed which investigated the efficacy of recycling lead or lead monoxide from various fire assay wastes including crucibles, cupels and slag. The scope of the project was to determine optimal hydrometallurgical parameters so that direct separation and recovery of lead salts was economically feasible. A process was developed from the study which could use either acetic acid or nitric acid as a leachant, followed by several precipitation processes which could directly recover litharge (PbO) or other lead salts, such as lead carbonate or lead sulfate. The economics of the process is discussed. Analytical equipment such as the atomic absorption spectrophotometer and x-ray diffractometer supplied much of the information required for the study. However some novel analytical approaches using these instruments had to be developed to help in the determination of leaching kinetics and process quality control which are discussed.

Jan 1, 1999

By Lennart Bergstedt

Boliden Aktiebolag, the prime base metal mining company of Sweden, annually treats some 11-12 million tons of sulphide ore in nine concentrators. Its first flotation plant was established in the early thirties for the complex Boliden ore. Since then, the number of mines and plants has gradually increased. Considerable effort has been devoted to the development of all phases of the technology of ore prospecting, mining, milling, smelting and refining. This has been necessary due to the complex and low-grade ores. The development of concentration has mainly been directed toward the arts of grinding and flotation. During the forties and fifties, open-stage fine crushing followed by two-stage grinding in rod and ball mills with cyclone classification was successfully introduced and used throughout the plants. The increasing cost of grinding media led to studies of an autogenous grinding technique as early as 1945. Basic test work commenced during the early fifties, with a. number of ores tested for pebble grinding. In 1956 a new pilot plant was built, with equipment installed for the continuous testing of pebble grinding and, later, for primary autogenous grinding of run-of-mine ore. The intensive test work showed that pebble grinding was feasible in almost all of the plants. At this early stage of testing, however, the merits of autogenous grinding could not be fully evaluated. As a. consequence the rod mill/ball mill grinding systems were converted to rod mill/pebble mill systems whereever possible. In parallel with the converting of grinding systems the development work concerning the merits of autogenous grinding went on. The major result

Jan 1, 1977

By P. R. Taylor

The ability to treat refractory gold concentrates that contain appreciable amounts of sulfur and arsenic, in an economic and environmentally safe manner is important to the gold mining industry. Processing alternatives include: autoclave oxidation, bacterial oxidation and roasting. Roasting may be the cheapest of all the alternatives if inexpensive methods can be found to contain the arsenic and sulfur. The research program, being reported here, has been evaluating the ability to use hydrated lime in the roaster to capture both the arsenic and the sulfur. Lime roasting is not a new idea, it was proposed for copper ores by Bartlett in the early 1970's (Bartlett and Haung 1973) and for cobaltite concentrates by Taylor in the early 1980's (Taylor et al., 1981). In addition, ores have been roasted that contained limestone and it was shown that partial capture of the sulfur was possible. Lime -sulfur containment has been proposed for the coal fired electricity industry, as well.

Jan 1, 1992

By M. E. Volin

The Buckeye manganese deposits are in Stanislaus County, Calif., about 33 miles south of Tracy. From 1917 to 1919 the deposits produced 13,370 tons of ore reported to average 46 percent manganese and 14 percent silica. The deposits are confined to two areas of' development, known as the north mine workings and the south mine workings, about 700 feet apart horizontally. Mineralization occurs chiefly as rhodochrosite and psilomelane interbedded in cherts of the Franciscan formation. As a part of the Bureau of Mines program of investigation and development of domestic mineral deposits, a development project was started November 25, 1940, and completed June 27, 1941. The Federal Geological Survey cooperated by mapping the topography and geology and logging the drill cores. The program included road and. trail building, trenching, underground excavation, diamond drilling, and sampling. The following pages mention the location, brief the history, and note the physical .features of' the district. Mine workings are sketched, the deposit is described, and the plan of the project is noted. The work performed by the Bureau of Mines is explained in the concluding pages with a summary of the drill-hole logs.

Jan 1, 1949

By R. J. McLaughlin

Acid mine drainage (AMD) can occur as a natural phenomenon through oxidation of sulfide minerals. Oxidation by air and water can be exacerbated by mining. Because AMD can exhibit low pH, it is capable of extracting heavy metals from mineral deposits. The result is highly acidic drainage with elevated heavy metal concentrations -the combination of which can cause extensive environmental damage. Because of the importance of these factors, this paper is focused on sulfate based AMD. Due to widespread mining, the occurrence of AMD is ubiquitous. As a result, several approaches to treatment have been developed. Chemical treatment using alkali is most commonly employed to treat AMD. There are alternative methods of treatment, as well as alternative ways of handling treatment sludges or concentrates. Dewatering of sludge or concentrates is beyond the scope of this paper.

Jan 1, 1996