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As part of the Bureau of Mines program to reduce U.S. reliance on foreign suppliers of strategic and critical metals, research was conducted to improve technology for the recovery of critical metals from hardface alloy grinding waste, a form of superalloy scrap. This report describes a hydrometallurgical process that demonstrated on a laboratory scale that 79 pct of the chromium, 97 pct of the cobalt, 99 pct of the manganese, 99 pct of the nickel, and 90 pct of the tungsten could be recovered in chemical form from hardface alloy grinding waste. The process involved deoiling the grinding waste, followed by chloride-based dissolution of the deoiled material. A high-grade calcium tungstate (CaW04) product was recovered from the resultant leach residue by caustic leaching and precipitation. Iron, cobalt, man-ganese, and nickel chlorides were sequentially recovered from the leach liquor by solvent extraction. Amine extractants were used to extract the iron, cobalt, and manganese; decanal oxime was used to extract the nickel. Market-grade cobalt chloride (CoCI2), manganese chloride (MnC12), and nickel chloride (NiCl2) products could be produced directly from the resultant strip liquors. The final raffrnate was a relatively pure chromic chloride (CrCI3) solution that compared favorably with commercial solutions.

Jan 1, 1988

By A. K. Singh

Between the main fan and the coalface in a mine a lot of air is lost through leakage at stoppings, doors, air-crossing etc. so that a much larger quantity of air has to be circulated by the fan in order that the stipulated quantity of air reaches the face. Stoppings are of vital importance not only for effective ventilation of underground mines but also for isolation of areas affected by fire or susceptible to spontaneous heating. Generally, isolation stoppings are made of brick in cement mortar. If the area is far from the pit or unapproachable, it is very difficult and sometimes impossible to build these stoppings. To overcome these difficulties, particularly near fire affected zones, an alternate successful attempt was made in Indian mines to make a plug underground, from surface through borehole, using cement concrete. In this paper the salient features of the methodology adopted for construction of the plug and the experimental procedure for the measurement of air leakage by SF6 tracer gas is described. Measurements of air leakage through rows of ventilation stoppings in two mines viz. Moira (Jambad and Kajora seams) and Kuardi11/12 (Niga seam) collieries of Eastern Coalfields Ltd. (ECL) have been incorporated. Results of experiments conducted at the Central Mining Research Institute (C.M.R.I) to determine leakage through25 and 38 cm thick brick stoppings are also discussed. Results of all these studies are compared, which show that the efficacy and reliability of the remote filled cement concrete plug in respect of air permeability is satisfactory.

Jan 1, 2004

By Robert Hopler

As a part of the depression and rectification work on the Port Morris branch of the Harlem Division of the New York Central & Hudson River Railroad, a short tunnel is being driven under St. Mary’s Park. The park is near 149th St. and St. Ann’s Ave., in the Borough of the Bronx, New York City.

Jan 1, 2006

By Thomas M. Barczak

This report examines practical considerations in longwall support selection that have evolved from Bureau of Mines ground control research. The scope of discussion includes trends in support selection, analysis of shield designs, performance testing, and an examination of support and strata interaction theories and their relevance to in situ support loading. Application recommendations are made for two-leg shields. four-leg shields, and chock-shields. Two-leg shields account for 67 pct of the current active longwall installations and are used in a variety of applications. Automated control systems are likely to continue to grow in utilization. The next major change in shield design is likely to be the application of wider supports. The most effective method of performance testing longwall shields is by controlled displacement of the canopy relative to the base. Controlled force application does not control the load transfer through the shield and may not produce maximum loading in all support components. Theories of estimating support capacity based upon a detached roof block that must be maintained in equilibrium by the powered support are being challenged by concepts based upon the equivalent stiffness of the total ground supporting system.

Jan 1, 1990

The Tenth International Conference of Directors of Safety in Mines Research was held in the United States from September 28 through October 2, 1959, at Hotel Webster Hall, Pittsburgh, Pa. The Conference was organized by the Federal Bureau of Mines. In accord with the program outlined at the Ninth Conference (1956, Heerlen, Holland), the papers submitted dealt with the following three subjects: 1. Safety of coal mine explosives 2. Explosion hazards in mines 3. Ignition and fires in mines Seventy papers were presented. There were eight technical sessions followed by an extended tour of the Bruceton facility of the Bureau of Mines on October 2. Simultaneous translation was provided in the three official languages of the Conference--English, French, and German.

Jan 1, 1962

Effect of Hydrophobicity and Frother Concentration on Bubble-Particle Interactions in Turbulent Flow

Sep 13, 2010

By Cadia Geology Team

The Cadia Hill Gold Mine, located near Orange in Central Western New South Wales, is owned and operated by Cadia Holdings Pty Ltd, a wholly owned subsidiary of Newcrest Mining Limited. Construction including pre-strip mining occurred from 1996 to 1998. The mine was officially opened in October 1998 following commissioning of the concentrator and mine fleet in June of that year. The Cadia Hill orebody is a porphyry related gold and copper system. The final pit has a strip ratio of approximately 1.3:1.0. Mining is undertaken on 15 metre benches using large capacity diesel hydraulic face shovels at an annualised rate of up to 70 Mtpa. The concentrator is currently rated at 17Mtpa and includes the worldÆs largest single line grinding circuit. The feasibility Mineral Resource was estimated at 352 Mt at 0.63 g/t Au and 0.17 per cent Cu. Initial reserves totalled 200 Mt at 0.74 g/t Au and 0.17 per cent Cu yielding a mine life of approximately 12 years. During the pre-production period mine geology systems were developed to support the operation. By design these systems were intended to add value to the business through minimisation of material miss-classification, provision of accurate and timely production information and mapping and reconciliation as a continuous model improvement tool. Variances that would prove to be material to the life of mine plan were recognised during the first year of production. These included identification of additional ore tonnes, higher copper grades and higher gold recoveries relative to the model. Gold grades and copper recoveries also reconciled favourably. Testwork was undertaken to determine the underlying causes of each variance. Re-modelling was then undertaken to capitalise on those variances. The Cadia Hill Gold Mine life of mine plan was re-evaluated with updated geology, grade, geotechnical, metallurgical and environmental inputs. Operating strategies were also reviewed and revised. Despite application of reduced metal prices in the evaluation, the outcome was one of extended mine life with more metal produced at lower cost. Development of robust mine geology systems, including a pro-active reconciliation process contributed to tangible improvement of the Cadia Hill Gold Mine operation. On-going system development and improvement initiatives are planned to add further value for the future.

Jan 1, 2000

By D Craw, D Wilson, D Chappell

Gold is extracted by cyanidation of a sulphide-rich concentrate at Macraes mine, and after cyanidation, the concentrate is discharged to tailings impoundments. The concentrate tailings were discharged to a dedicated concentrate impoundment from 1989 to 1993, afterwhich they were blended with the flotation tailings. Since mid-1998, concentrate tailings have been redirected to the dedicated concentrate impoundment. The concentrate tailings contain up to 1 ppm gold, and will be reprocessed in the future. However, it is a regulatory requirement that a contingency plan be in place to rehabilitate the concentrate tailings should the mine operation cease for any reason. Initial predictions suggested that the sulphide-rich tailings would oxidise and acidify, creating a potential long term environmental problem. Investigations of the state of the tailings after 4 years show that these predictions were overly conservative. Only minor oxidation has occurred in the upper 2 metres of the tailings where the pH has locally dropped from 10 (discharge condition) to between 7 and 8. Below 2 metres, the tailings are essentially unchanged from their deposition state. The low rate of change in the tailings is due to their very low permeability which in turn is a consequence of the fine grain size (ca. 15 ¦m). Dewatering is extremely slow, and incursion of oxygenated water is negligible. Calculations suggest that water movement over 30 m will take at least 100 years and possibly 1000 years. The contingency plan is to capitalise on the very low permeability and keep the tailings from drying with a semipermeable cap. A layer of limestone will be added to the top of the tailings, beneath the cap, to enhance alkalinity of any percolating water. If acidification does occur, contrary to expectations, any acid produced will be neutralised by underlying calcite-bearing schist, schist in the concentrate impoundment wall, and the flotation tailings immediately downstream. In addition, dilution by alkaline ground and surface waters would further ameliorate any acidic discharge.

Jan 1, 1998

Ore sorting is a high capacity, low cost method of pre concentrating ores and in some cases of producing a marketable concentrate. In most cases it is applied to run of mine material, immediately after primary crushing and screening in sizes ranging from 10 mm to 150 mm. Recent developments in bulk sorting of friable uranium deposits have resulted in machines capable of handling fine materials with sensing and separation being achieved on a zone by zone basis. Modern ore sorting machines rely on the synchronous operation of four internal subsystems, feed presentation, sensing, data processing and separation. A variety of different sub systems is available which can be combined in various forms to produce sorters capable of handling a wide variety of mineral types. The benefits in using ore sorting cover a wide range of situations and are applicable to both established mines as well as new mining ventures. Reduced operating costs, increased productivity, capital savings, energy and resource conservation and environmental issues are all part of the reason why ore sorting is finding rapid acceptance in today's mining industry. The suitability of different ore types for pre-concentration using anyone of the variety of ore sorting systems can be quickly established using computer based techniques which require only small samples of the materials under investigation.

Jan 1, 1980

Scenario reduction is designed for selecting a representative subset of geostatistical simulations out of a much larger set. Three steps are involved: measuring the dissimilarity between two simulations; finding a metric to measure the distance between any subset of k simulations and the full set of N simulations; and finding an efficient algorithm for selecting the subset that minimizes the metric. This paper focuses on the third question. We show that genetic algorithms are an efficient way of approaching the minimum when the population of subsets to be sampled is large. Two case studies based on the Walker Lake data-set are presented: firstly choosing k=4 simulations out of a total of 100, and secondly choosing 20 out of the same 100 simulations. In the first case it was possible to compute all possible combinations exhaustively and hence to demonstrate that the algorithm converges to the true minimum. This was not possible in the second case. Instead we demonstrate that it outperforms the random draw algorithm used in earlier work. A procedure for tracking individual selections during the iterative procedure was developed. This allows us to measure the evolution in the percentage of progeny resulting from crossing-over and from mutation that survived in the next generation. It gives valuable insight into how to choose the parameter values in the algorithm. Another key finding is that there is a trade-off between the number of individuals per generation and the number of generations required for the algorithm to converge.

Jan 1, 2014

By Aparup Chattopadhyay, Barun K. Gorain

"Porphyry copper deposits are the most important source of copper and also gold within the orogenic belts. These deposits are characterized by low grade copper ore (0.2% to 1% copper) and host precious metals like gold, silver and platinum. A characterization tool has been developed for complex porphyry type copper-gold deposits with an aim to quantify copper and precious metal deportment. This quantification is a challenging task due to low grades and also due to the presence of both visible and invisible precious metal content in different sulphide and non-sulphide phases. Studies were initiated on various complex ore deposits and also on samples representing various processing streams such as flotation and leach products. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metals content in various species. The relevance of this characterization to metallurgy will also be briefly discussed in this paper.INTRODUCTIONA novel characterization tool has been developed for double refractory gold ores and complex copper-gold ores using state-of-the-art technology for quantitative gold and copper deportment study. The characterization of these ores is a challenging task due to low copper and gold grades in ores, presence of both primary and secondary copper sulphide phases and variable proportion of visible and invisible gold in different sulphides phases (pyrite, chalcopyrite, chalcocite and bornite) and iron oxide phases (magnetite, hematite and goethite). A study was initiated on various ore deposits and also on samples representing various processing streams of pilot plant batches such as flotation concentrates and tailings. This paper attempts to discuss the deportment characterization methodology through presenting results from investigations on four samples from a flotation circuit viz, Feed, Final concentrate, Cleaner Scavenger Tail and Rougher Tail samples. These four samples represent the key streams for a typical copper-gold flotation flow sheet. The key objective of this investigation was to identify and quantify visible and invisible gold along with understanding the morphology and liberation of gold associated with various sulphides, Fe- Oxides and non-sulphide gangue species. In addition, the aim of this study was also to relate this mineralogical and gold deportment information to metallurgical performance."

Jan 1, 2013

By Charles E. Whieldon

Data on the oil fields in Mahoning Columbiana, Carroll, Jefferson, and Harrison Counties, Ohio, were collected from scattered sources and com- piled to make the information readily available to operators who may be interested in conducting secondary-recovery operations in the area. General geology, oil production, oil-productive acreage, core data, reservoir calculations by townships, and miscellaneous data and reference material are presented.

Jan 1, 1965

By D. J. R. Ras

A sub-level open stoping method is being used to mine the massive deposits at TARGET Gold Mine which uses cemented tailings to backfill the stopes. This requires the construction of bulkheads to contain the freshly placed backfill, capable of resisting the hydraulic pressure imposed by filling. The bulkheads must contain an 8 metre head of backfill slurry within 48 hours and withstand the force exerted by a 35 metre load of consolidated fill at a maximum estimated fill relative density of 1.9. After a variety of methods of construction were evaluated, it was decided to construct the bulkheads using the low density, fast-setting foamed cement-based product TEKSEAL HS manufactured by MINOVA RSA. The cement foam is contained between low-cost steel and fabric brattices which are easy to construct, using a method specially developed for the TARGET bulkheads. The paper will describe the design, trialling and construction of the bulkheads, and results obtained to date.

May 1, 2007

Iron production in one year exceeds that of all other metals combined in ten years. It is a huge industry that started from a modest furnace producing one - two kilograms metal per day to a gigantic reactor producing 10 000 tons per day. The major milestones of these developments are reviewed.

Jan 1, 1999

By A B. Christie, R L. Brathwaite, A Swain

This study provides quantitative data on vein distributions within seven selected epithermal systems, four deposits hosted predominantly in rhyolitic rocks: Ohui, Wharekirauponga, Neavesville and Komata, and three major deposits mainly hosted in andesite: Martha Hill, Golden Cross and Karangahake. The technique of fractal analysis was used to help quantify vein distribution patterns. The fractal dimensions (D) obtained are related to the number of veins per metre, the degree of vein clustering, and vein thickness. An increase in any of these tends to increase the fractal dimension.   It is the relative relationship of these parameters that is important for the characterisation of vein distributions, and the comparison of different deposits. Within the same systems, the rhyolites are characterised by lower vein thickness and vein density, but have a higher degree of vein clustering compared to the andesites. Sections that are deeper and more centrally located within the epithermal system and/or close to major structures tend to have a greater degree of vein clustering, higher average vein thickness and density, and higher thickness to density ratios. This depth control is most pronounced in epithermal gold-silver systems because they have formed at shallow crustal levels where physico-chemical conditions change drastically both vertically and laterally. In addition to lithological and structural control at vein scale, deposit scale structure is of great importance in the deposition of economic mineralisation. Large open vein structures capable of sustaining high fluxes of hydrothermal fluid, favourable for the formation of large, high-grade gold deposits, are best developed in andesite sequences.

Jan 1, 1995

New Zealand has been a significant producer of gold for over a century. Total recorded production is over 850 tonnes. There were three major periods of production: the first and biggest was between 1860 and 1880, the second was between 1895 and 1920 and the third was between 1930 and 1945. After 1945 gold production fell continually until 1980 when the major upward adjustment in gold price led to renewed interest. There have been important new developments in each of the known gold-rich areas: Westland, Otago and Coromandel and exploration for gold in these areas and in previously unprospected regions has reached unprecedented levels.

Jan 1, 1988

By Ali Ameli

Design loads are limited for piles relying upon toe stresses in rock due to uncertainty about the rock quality over the whole pile diameter because of rock mass properties or construction effects. The paper discusses the use of video images to evaluate rock quality at the bottom of piles socketed into graniodorite bedrock in a steel pipe pile project. Skillful interpretation was required to assess the 3D properties of the rock from video images. It is necessary to observe the rock mass characteristics near the project site for better perception of the rock features from the images. Video image interpretation skills were established by the evaluation of the cores drilled under the socket base and the results of pile loading tests. Correlations were found between rock appearance in the images and the rock socket drilling records. Rock socket acceptance criteria were developed through monitoring the drilling operations for the specific site procedures. Video images then served as one of the quality-assurance tools together with probing and pile loading test. Lessons and methods learned from video inspection in this project could be used to evaluate rock quality in similar cases.

Jan 1, 2006

Syncrude Canada produces a large part of Canada’s crude oil supply. The company processes about 225,000 bbl/day. The oil produced is used for jet and automobile fuel, home heating oil, plastics and other consumer synthetics. Crude oil is produced through a process of mining, extracting and upgrading bitumen. A rich supply of bitumen is contained in the Athabasca oil sands deposit in northern Alberta. Tailings from the bitumen processing are sent to a settling basin.

Jan 1, 2000

By K. Swedburg, M. Samuels

"The New Afton concentrator was commissioned in June 2012, reaching the design milling rate in September 2012. By late 2013, through a campaign of optimization and de-bottlenecking, it was recognized that the installed plant was capable of greatly exceeding the design throughput of 11,700 tpd. Because the value of the metal contained (by increasing the plant feed rate) exceeded the offsetting losses of copper and gold recovery (as the operation moved to a coarser grind), the concentrator feed rate was strategically increased with support of New Gold, while the operations team was given a mandate to evaluate, and then implement, flow sheet options that could re-establish the original design criterion grind target and achieve the corresponding improved recovery. Broadly, the two options implemented were the addition of a tertiary grinding stage consisting of Metso Vertimill® prior to rougher flotation (in order to address the grinding required at increasing throughput by increasing the power), and the addition of three Woodgrove Staged Flotation Reactors (SFR) added to the cleaner circuit after regrind of the rougher concentrate (to address the increased mineral loading to the cleaner circuit). Through test work, it was anticipated that the SFRs would be capable of achieving final concentrate grade in a single pass without the integration of recirculating loads, a strategy sometimes referred to pre-cleaning. This paper describes the expectations generated for the Woodgrove SFR unit operation through pilot plant testing on site, and compares those results with the performance of the expanded circuit that exceeded the original design criterion of P80 160 µm, which was commissioned in the second quarter of 2015.INTRODUCTIONThe New Afton concentrator, located near Kamloops, BC Canada, commenced operation in June 2012. The mill achieved the design throughput of 11,000 tonnes per day average during the month of September 2012 and, following various operational optimization efforts (O’Hara et al, 2015), achieved the design p80 grind size of 160 µm at the design milling rate in July 2013.During August 2013, trials were carried out to determine the throughput rate limits of the mill circuits and to evaluate mill metallurgical performance at higher rates. Milling rates up to 15,500 dmt per 24 hours were achieved during this trial, demonstrating potential capability for sustained milling rates exceeding the nominal design capacity. As was expected, the higher milling rates resulted in a coarsening of the grinding circuit product size, and resulted in marginally lower recoveries in the rougher flotation circuit. Despite the lower recoveries, the higher milling rates resulted in higher metal production and the financial analysis favored running at rates of at least 13,000 tonnes per operating day, with the higher cash flow in the near term offsetting the value of metal production loss at the end of the mine life (due to the short term increase in the rate of reserve depletion). Milling rates were sustained above 13,000 tonnes per day through the second half of 2013, and increased above 14,000 tonnes per day by mid-2014 (Figure 1)."

Jan 1, 2016

By Guangyi Sun

Wall rock classification method for coal mine support is the main factor affecting mine support. It is greatly affected by the combined effect of randomness, fuzziness and human being's incomplete knowledge. There are several coal rock classification methods. Using different rock classification methods the same engineering rock mass can be classified into different classification leading to different construction practices.

Jan 1, 2005