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R. C. BUCKETT (Lake View and Star Limited) : At the outset I should like to add my congratulations to those already extended to Mr..Norwood on his excellent paper, which has given us all an inspiration to strive further to improve our plant recoveries. In some respects this paper has left us so little to discuss without considerable time spent on. further research work. At all points one is met by a baffling array of facts which leave one feeling hesitant to speak.The careful and methodical way in which Mr. Norwood went along step by step until all channels of research presenting themselves were tested to his own satisfaction leaves me with but a few comments to make. Particularly striking to me is the explanation of the residual gold values in calcines by recrystallization of haematite and here is a line to be attacked by future studies. This will be mentioned again later.Particularizing on the paper, the first point that struck me was the method of change of pyrite through to the final haematite. I have never been able to satisfy myself that a sample taken from various positions along a roaster when cooled, as described on p. 397, represented a fair sample of the conditions at that point, but I must confess that I have not found a substitute that did satisfy me.However, the following figures are illuminating... But to fill dry a receptacle of known volume with calcines, as described by Mr. Norwood, gives the following apparentspecific gravities:

Jan 1, 1940

By D Craw, R Norris

The Golden Bar pit is part of the Macraes mine, the largest gold mine in New Zealand. The Macraes mine is mainly developed in the late metamorphic Hyde-Macraes Shear Zone. However, the Golden Bar pit was developed in a mineralised zone about 200 m structurally above the Hyde-Macraes Shear Zone. The host rocks are dominated by massive quartzofeldspathic schist (5 - 10 m layers) with minor intercalations (1 - 5 m scale) of micaceous schist. All the host schist has disseminated pyrite (micron to mm scale) from pervasive late metamorphic hydrothermal alteration.   In addition, there has been more localised (metre scale) relatively intense hydrothermal alteration controlled by shears subparallel to foliation. Gold occurs in three types of mineralised rock: silicified schist, which dominates, fissile black sheared rock, and cross-cutting quartz veins. There are three principal structural zones in the deposit: 1.   a strongly sheared micaceous and graphitic zone at the base of the structural sequence; 2.   a weakly deformed schist zone cut by relatively flat-lying (= 20¦ dipping) quartz veins; and 3.   a stack of imbricated schist pods and deformed silicified schist confined between two sub-parallel low-angle (ca. 30¦) shears.   These structural zones were juxtaposed during thrust deformation. The lower black shear zone has m-scale folding and over-thrusting packages, kink folding and foliation stacking with associated striations that imply west-directed thrusting. Striations and imbrication geometry between the upper two shears imply oblique thrusting that was directed towards the west. Post-mineralisation normal faults locally disrupt the mineralised zone. The Golden Bar pit mineralised zone has some of the structural and mineralogical characteristics of the main Hyde-Macraes Shear Zone, and may be genetically related.

Jan 1, 2006

Man’s search beneath the earth for minerals has always required light, and the devices used to provide illumination have been both innovative and unusual —from stone vessels holding fat and a wick of grass or fiber to a shower of sparks produced by a thin steel disc. While the date when lamps were first used in mines is unknown, Greek and Roman records from 3000 BC definitely mention their use in underground mines. Early Remans most likely used a lamp similar to the one depicted at right. Over the ages, various types of devicives and methods of illumination have been tried and used. One interesting scheme for underground light was to reflect sunlight down the shaft and along drifts using mirrors or other reflective materials. Bunches of resinous wood were also used for underground lighting in many parts of England. In the mid-18th century, the speding mill was developed in England. It worked by rapidly turning a thin steel disc against a flint, causing a shower of sparks to appear. The light produced was uncertain, highly variable, and unsafe in gaseous environments. In Europe, an open pan-type hanging oil lamp was developed and used in some operations in the 1700s. This type of lamp had one opening for a wick and a second opening for refilling the oil reservoir. The lamps were embellished with goad luck charms – a good luck rooster was used in many parts of Europe while a frog and “gluck-auf” were used in Germany. These lamps were introduced in Mexican mines, and a few have found their way into the southwest US. By 1850, a small wick lamp known as the lard-oil lamp, which resembled a tea pot, was invented in Scotland. These lamps were fueled with grease from a packing house –lard, bacon grease, or tallow. Whale oil was also used. Many improvements were made on these lamps, such as the use of windshields and the attachment of miners’ candle-holdm to support the lamp. While these lamps were handy and inexpensive to operate, they were dangerous because their large flame could ignite support timbers or other flammable materials. Miners from the United Kingdom brought this type of lamp into the US. Domestic producers of oil wick lamps were primarily located in Hazleton, PA; What Cheer, IA; Pittsburgh, PA; and Frostburg, IN. The first patent for an oil wick lamp was granted to W. Seybold of McKeesport, PA. Incidentally, these lamps were advertised in a 1903 Sears-Roebuck catalog for 10 cents apiece. Oil wick

Jan 7, 1980

By Tobias Hansson

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

Jan 1, 2000

By T. A. Ngcobo

Paper written on project work carried out in partial fulfilment of BSc Eng (Mining)degree The purpose of this report is to assess the risks faced by mines in dolomitic compartments in particular Kloof 8 shaft. The dolomites of the West Rand comprise one of South Africa?s most natural water resources, and overlie the reefs of the richest gold mines in the world. The pumping of water from the dolomitic aquifers to prevent flooding has caused the natural water table to subside, and the resulting cavities within the dolomite rock formations that overlie many gold deposits sometimes collapse, causing sinkholes. These impacts of the mining industry could worsen over time if preventative measures are not taken. This report discusses these impacts in detail, more specifically the risks to which operations in dolomitic compartments are exposed. A risk analysis was carried out to access the risks that the organization could face and it was this analysis that allowed one to examine the best methods to combat the problems. Other factors such as geological features and seismic events were also considered for the evaluation. To aid with the completion of this work various resources were utilized. A literature study was undertaken, information was gathered from various experts who specialize in dolomitic studies, evaluations were conducted and conclusions reached. The results from the project indicated that preventative measures should be implemented and correct procedures put in place to prevent any disasters.

Jan 1, 2006

By G. Price

The Building Research Establishment installed a base load cell in a driven cast-in-place pile prior to it being tested under vertical load. The monitored base loads were found to be significantly less than could have been predicted by current design methods. The less than expected capacity was attributed to the drilling out procedure. An electro-level system installed in a second similarly formed pile, provided detailed information on the performance of the pile under lateral load. The information obtained was used to check several current design methods for laterally loaded piles. The findings show the potential dangers of attempting to improve design parameters from only limited performance data.

Jan 1, 2010

Baja Mining is currently constructing the Boleo metallurgical plant in Santa Rosalia, Mexico to recover copper, cobalt, zinc and possibly manganese products from the Boleo ore. The process involves an acid seawater leach of the whole ore followed by solid-liquid separation and washing of the leach residue. Solvent extraction is used to separate copper, cobalt and zinc from solution. Copper and cobalt are recovered as cathode metal products and zinc as a zinc sulphate monohydrate. Manganese may be directly precipitated as manganese carbonate which can be used as a feedstock for manganese metal production. Laboratory testing has continued to refine various aspects of the process including iron removal, cobalt and zinc solvent extraction, cadmium cementation, cobalt electrowinning and manganese metal electrowinning. The results of this testing are reported in this paper.

Jan 1, 2012

By F. M. C. C. Vieira

The work described forms part of a Safety in Mines Research Advisory Committee (SIMRAC) funded project, currently an ongoing programme of research aimed at providing ?improved criteria, guidelines and the use of numerical models to design mine layouts at depth, so as to reduce seismicity and enhance worker safety?. The entire project deals with a number of distinct, albeit interrelated, research areas such as: subsidence and caving in hardrock, general numerical criteria for layout design, regional benefits of backfill, concrete pillars, strike stabilizing pillars and bracket pillars. This paper will focus on the last two items only. New considerations for the design of both stabilizing pillars and bracket pillar layouts are briefly discussed.

Jan 1, 1998

By S. Christiansen, G. R. Winslow, R. W. Kobler

Todays End of Life vehicles are shredded and their metal components recovered and recycled by standard methods. The remaining non-metallic fraction is shredder residue, and contains vast amounts of high value engineering plastics. None are today recovered. Discussed are the developmental approaches used in the first process to recover these valuable plastics. Examined are initial laboratory studies, pilot plant design and construction, product development, results, and flowchart explanations.

Jan 1, 2001

By Bill York-Feirn

The Colorado Mine Safety & Training Program (MSTP), in late 2005, completed and began distributing two new training tools; one geared to underground coal mine foremen and the other to surface aggregate employees. Through strong partnerships with MSHA, Colorado Coal Mine Board of Examiners, Colorado Mining Association and the Colorado Rock Products Association, the MSTP continues to create innovative and interactive training tools for not only Colorado, but for the national mining community. "Although we shoot and produce these materials in Colorado, it's important to us to make sure they are useful nationally," said Bill York-Feirn, MS TP Manager. The interactive DVD program "Underground Mine Foreman Certification Study Guide (Coal)," was completed in October 2005. It won the 2005 Grand Prize at the MSHA National Training Materials Competition in Beaver, West Virginia. [ ] This program is fully based upon the requirements of Title 30 Code of Federal Regulations (30 CFR) Parts 48, 50, 70 and 75 for underground coal mine foremen. It contains eight modules plus immediate access to relevant laws in the appendix. Topics covered include: Federal Law, Practical Math Skills, Mine Gases, Ventilation Maps, and scenarios addressing a variety of practical mining concerns. The DVD is designed for self-¬paced study and practice.

Jan 1, 2006

By Miller F. S

The famous Golden Mile of Kalgoorlie in Western Australia was, between 1888 and 19ft, one of the richest and most important gold camps in the world. Annual production, which reached a peak of nearly 1,300,000 oz. in 1903, however dropped to below 400,000 oz. after 1920.Depression seized the camp, and many mines closed down. The output from this old field is now steadily mounting under the stimulus. of a higher price for gold. In 1935 300,000 oz. of precious metal were recovered and the future is bright. Total production from the field is 21,400,000 oz., whereas something like £23,600,000 have been paid in dividends.The Golden Mile has been studied by many geologists. Their somewhat diverse findings were published for the most part in the Australian technical press which, unfortunately, is not sufficiently represented in foreign libraries.The following article is based on an eighteen months' study in the district for Gold Mines of Kalgoorlie Ltd., preceded by four years' experience with almost identical rock types in the, Porcupine district of Ontario. The excellent record of observed fact left by previous invesigators, augmented by talks with observant mining men...

Jan 1, 1937

By D. Turk, P. Lefebvre, J. Sargent, K. Major

"Stillwater Mining Company recovers platinum and palladium from their Nye Montana operations. Mining first commenced at Nye in 1987 at a milling rate of 455 t/d (500 stpd). The plant was expanded in 1995 with the replacement of the ball mill and the addition of flotation capacity to increase mill throughput to 1820 t/d (2000 stpd). The applications for platinum and palladium have increased in recent years particularly in the automotive industry and the supply of the metals has remained fairly constant with prices for both platinum and palladium increasing and remaining very stable. In 1997 Stillwater initiated the expansion of their operations to increase production of platinum and palladium. Projects were initiated to expand production at the Nye operations, increase smelter and refining capacities at the Columbus facilities and to develop the extension of the orebody at the East Boulder site. This paper will discuss the changes at the Nye concentrator which were completed to increase production from 1820 t/d (2000 stpd) to 2730 t/d (3000 stpd) and eliminate some of the process bottlenecks.IntroductionStillwater Mining Company is mining the only significant primary source of PGMs outside of South Africa. The J-M Reef is an extensive mineralized zone containing PGMs that has been traced over a strike length of about 43 km (27 miles) in the southwest region of Montana. Stillwater controls the entire PGM mineralized zone.Johns-Manville geologists discovered palladium and platinum in the early 1970’s. In 1979, a Manville subsidiary entered into a partnership with Chevron, USA to develop the project. In 1 987, operations at the Stillwater property near Nye, Montana commenced."

Jan 1, 2000

The Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House on Wednesday, 23rd August, 1978. Mr P. A. von Wielligh (President) was in the chair and declared the meeting open at 16h00. Obituaries The President: It is my sad duty to announce the death of the following members of the Institute : T. K. Prentice and W. E. Gooday, Honorary Life Fellows and Past Presidents; B. S. Allen, J. A. Becking, L. H. Mellor, C. A. Pratt and W. T. Stobart, Life Fellows; J. P. Burls, E. Cameron, M. L. Fitzgerald, C. G. Hinds, A. J. Patrick, H. O. Reisener, N. D. Shuttleworth, N. Soldan and J. Whitehouse, Fellows; T. Gemmell, J. S. A. Oelofse, W. D. Rowe, R. L. J. Shearman and G. M. Thain, Associates. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, I ask you to rise and observe a few moments' silence. Welcome The President: It is now my very pleasant duty to welcome our distinguished guests and visitors. We are pleased to have with us Mr D. A. Etheredge, Vice¬President of the Chamber of Mines of South Africa, and Mrs Etheredge. Mr Etheredge this afternoon represents the mining industry at our meeting. The importance of the close link that over the years has been maintained between the industry and our Institute speaks for itself. We are, therefore, grateful that he and Mrs Etheredge have managed to find the time to be with us this after¬noon.

Jan 1, 1979

By Andy Cole, Ken Thomas, Stephen Durn, Jacques McMullen

"The roasting and gas handling circuits of the Barrick Gold’s new Roasting Facility at the Goldstrike Mine in Nevada, USA incorporate well proven technologies in a unique combination. During the design of the plant, every effort was made to utilize the best available technologies from the perspective of capital, environment and operating costs.Product from the up-stream dry grinding circuit requires roasting to maximize gold recovery. The roaster utilizes Freeport-McMoRan whole ore roasting technology with pure oxygen as the oxidizing gas. This process was chosen based on its proven application on Carlin-type “double refractory” ores. Double refractory is indicative of the gold being difficult to direct leach due to a combination of pyrite encapsulation and the carbonaceous preg-robbing of the ore.A very extensive gas cleaning train follows the roaster and comprises direct cooling, dust scrubbing, indirect cooling, wet electrostatic precipitation, mercury scrubbing, SO2 scrubbing, CO incineration and NO, reduction before venting to the atmosphere.The roasted calcine is quenched, neutralized and then thickened before leaching in the carbon-in-leach-circuit.INTRODUCTIONBarrick’s strategic development plan integrated the production of gold from Goldstrike’s carbonaceous ore reserves by 2000. A due diligence review of carbonaceous ore processing options was initiated during the second half of 1 996. Processes considered included autoclaving followed by a proprietary ammonium thiosulfate leaching process, fine grinding/autoclaving as practiced then by Santa Fe, and whole ore roasting as practiced by then Independence Mining and Newmont. The objective by year-end was to recommend the most robust and economical process for Goldstrike’s carbonaceous resources. In the fall of 1996, a detailed review of roasting as a processing alternative for Goldstrike was initiated."

Jan 1, 2001

Caving of the second lift of the E26 orebody at Northparkes Mines was monitored with a comprehensive package of instrumentation, including an ISS seismic monitoring system. Seismicity was collected by an array of 19 triaxial accelerometers and 9 uniaxial geophones, giving a high quality seismic data set. The seismic response to block caving at Northparkes has been divided into two papers. The first paper focuses on the seismicity during undercutting. The second paper deals primarily with the seismicity during cave propagation during initial cave production. In this paper, traditional seismic monitoring concepts are applied to seismicity during cave mining. More than 40 000 seismic events were recorded during cave undercutting between February and January 2004. Events up to local magnitude +1.3 were recorded near the mine during undercutting, with event rates of up to 500 per day. Analysis of frequency-magnitude distributions, S-wave to P-wave energy, and temporal variations in event magnitude all gave insight into the seismicity recorded. In addition, a new technique, called apparent stress time history, was shown to be sensitive to stress change from undercut blasting, and useful to identify significant periods during cave development. A significant difference was identified between the cave back location and the halo of seismic events above the cave. Throughout the undercutting, the a seismic zone of loosening was typically 50 to 70 metres in vertical thickness. Based on the seismicity, a stress driven rock mass failure model is proposed. Early in the undercutting, seismicity and movements in the seismogenic zone were directly triggered by stress change from undercutting. Towards the end of undercutting, seismicity was virtually uncorrelated with undercut blasting, and likely due to the onset of cave initiation.

Jan 1, 2008

The Bagdad mill, built in 1977, was de-signed for a mill capacity of 36,300 tpd. An ABC (Autogenous Mill-Ball Mill-Crusher) grinding circuit was chosen. The original mill contained three completely independent grinding circuits, each containing one 9.75 m diameter by 3.96 m long fixed speed autogenous mill, one 4.72 m diameter by 6.71 m long ball mill and one 2.13 m diameter short-head cone crusher. Total installed power per grinding circuit was 8,464 kw with 5,966 kw in the autogenous mill, 2,237 kw in the ball mill and 261 kw in the crusher. (See FIGURE I--Major Equipment Flow Diagram.) The autogenous mills were designed to be able to operate semi-autogenously but were never converted to SAG. As a result of this design, only about 4,100 kw of the designed power is utilized in the autogenous mills. The grinding circuits are closed with 2.44 m by 6.10 m double deck vibrating screens. Screen oversize is returned, by a series of conveyors, underneath the mill coarse ore stockpile to feed the crushers. Variable speed belts feed the crushers and control power draw. Crusher product reports directly to the tail end of the autogenous mill feed belt. (See FIGURE 2--Typical Crusher Feed and Product Size Distributions.) Tramp iron in the autogenous mill-crusher circuit is handled in a unique way. A magnetic sensor detects the metal. This closes a gate which directs the crusher feed onto a separate belt which bypasses the crusher and returns the material to the autogenous mill feed belt.

Jan 1, 1992

By J. F. T. Agapito, R. R. Goodrich

Yield pillars have been used for many years to help reduce stresses near mine openings and improve roof and floor stability. A yield pillar is often defined as a pillar that fails but retains residual strength. Stress transfer occurs through the roof and floor after the peak strength of the pillar is reached. High stresses are transferred from around the openings onto abutments that can be barrier pillars or unmined ground. This mechanism, often referred to as pressure arching, is possible as long as the width of yield pillars is less than the critical width above which stresses cannot be carried by the overburden. Significant stress transfer also can occur due to small amounts of pillar and/or floor yielding before the peak strength is reached. This is accomplished in a quasi-elastic manner with little or no visible roof and pillar fracturing or floor heave. Long-term stability may be achieved when stresses and mechanical properties are favorable to pre-failure yielding. This paper gives practical examples where improvements in stability and resource recovery were achieved with this mechanism. Yielding was assessed by comparing measured and calculated vertical pillar stresses. Results indicated that calculated stresses in the pillars were 25 to 40 percent higher than the measured stresses, demonstrating significant arching load transfer to the abutments. Pre-failure yielding is probably often present but unintentional in both development and production areas. Better recognition and use of this mechanism should lead to improved designs as mines become deeper.

Jan 1, 2001

By R. Al-Hent, M. Aissa, J. Asfahani

"This paper focuses on determining the favorable geological and hydrogeological conditions for forming uranium occurrences in the Froqlos-Jabal Abou Rabah region, Palmyrides, Syria. Eighty rock samples from this area were analyzed by spectrometric gamma-ray technique to determine the radioactive concentrations of eU and eTh, and of %K. Uranium concentrations in shallow and deep groundwaters were also determined. High uranium concentrations were registered owing to the presence of phosphatic outcrops in the study region. The uranium migration trends and its remobilization were analyzed through the analysis of the behavior of eU, eTh, and their ratio. A positive relationship between eU and eU/eTh, and a negative relationship between eTh and eU/eTh in geological formations of different ages supports the secondary remobilization of uranium. The role of groundwater movement in transportation and redeposition of uranium mineralization is discussed: deep waters are less oxidizing than near-surface waters, and do not appear to have significantly remobilized uranium. This indicates that the source of secondary uranium mineralization is surficial or near surficial, and is mainly related to the leaching of outcropping phosphatic layers.Integration of the results with established radioactive and geological sections reveals four radioactive anomalous zones: north Froqlos, Kherbet Hannora, northwestern flanks of Jabal Abou Rabah (Kherbet Al-Hajar), and the northwestern limit of the Ghuntor depression. The high uranium concentration in north Froqlos is because of its original presence in the phosphate beds and extensive fracturing, which allows groundwaters to penetrate and remobilize the uranium. High uranium concentrations in the other three locations are caused by the presence of evaporites and capillary action, which draws solutions upwards and causes redeposition as surface crusts (gypcrete)."

Jan 1, 2009

THE National Safety Council will hold the following ses-sions in the Waldorf-Astoria Hotel, New York, N. Y., on Oct. 2, 3 and 4: Oct. 2. 9.30 A. M. 1. Report of past year committees, by Chairman 2. "Safety Pays," by Howard I. Young, Vice-President, American Zinc, Lead and Smelting Co., Mascot, Tenn. (Discussion) 3. Entertainment 4. "Methods and Results of Improved Foremanship Conferences," by H. A. Gilbertson, Director of Per-sonnel, Lehigh Coal and Navigation Co., Lansford, Pa. (Discussion) 5. Appointment of election and resolutions committees Oct. 3, 9.30 A. M.

Jan 9, 1928

Upon cessation of mining activity open-cast mine pits typically fill with water, forming a æpit-lakeÆ. The water in these lakes, in some instances, contains high concentrations of ædeleteriousÆ material. Containment and/or dilution typically requires an understanding of how stratification in the pit-lake will develop over a long timescale (say 100 years). Vastly different transport rates can develop due to differing hydrogeochemistry, basin morphology and climate. Numerical (computer) modelling is the most likely approach for successful prediction over long times. While lake modelling tools are available, useful numerical modelling requires improved understanding of transport in such systems because they are different to natural lakes in a number of ways. Notwithstanding the effort required to improve our understanding, the modelling provide a means of testing approaches to active management of pit-lakes.

Jan 1, 2002