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By Yaw Boadi, Andrew McCallum, Sandy Gray, Yavuz Atasoy, Peter Wemyss

"Various full-scale test programs and installations of the InLine Pressure Jig (IPJ) have provided evidence that pre-concentration of the difficult to leach sulphide mineral through gravity can provide significant increases in economic recoveries. The continuous gravity concentrates are intensively treated either by re-grinding or Intensive Cyanidation. Data from various mine sites worldwide is presented. Treatment of complex ore bodies with this low cost methodology may render previously uneconomic ore bodies financially viable and assist in the recovery profile of transitional ore.INTRODUCTIONThe use of gravity is made extremely attractive in complex ore situations due to the low cost of operation, typically a few cents per ton operating cost and lack of chemicals.Gold mines which suffer from poor recovery due to complex mineralogy such as Stibnite, Arsenic, Carbon, Telluride, Silver and other pacifying agents such as Iron, which can form coatings, can all benefit from the process proposed in this paper. The key issue is not overall recovery as much as one of economic recovery. The key to this is maximised recovery at the lowest possible capital and operating cost. Other options such as flotation are reviewed but are not seen in many instances to be the panacea due to issues discussed in the paper. The use of the InLine Pressure Jig in the re-circulating load of the milling circuit is a cost effective means of recovering a sulphide/gold concentrate containing the complex mineral assemblages which require re-grinding and intensive leaching for optimised gold recovery.The benefits of Jig Assisted Grinding (JAG) are many and the challenge over the past years has been developing, understanding, implementing and evaluating the benefits of various flowsheet models. This has involved the reconciliation of results in plant scale trials back to the original laboratory test program. The following paper outlines the insights gained in this area through extensive work carried out by many people across both laboratories and plant sites in Australia and overseas. The examples in this paper are some of the work carried out on a few selected sites but similar work has been carried out on other sites such as Penjom, Granny Smith and Agnew. This work has eventuated in several installations which we believe have great importance in the future of the gold processing industry. They will lead the way forward to the modern all-gravity plants of the future.Compared to flotation, for the recovery of sulphides, gravity is a simple option. The simplicity generally translates to low capital and operating cost."

Jan 1, 2004

By Yates C, Gillie E. W, Finucane K. J

During the year 1940 a complete investigation was made of the whole of the stoping operations throughout the Great Boulder Mine and, as a result, it was decided to convert some of the existing shrinkage stopes into cut-and-fill stopes, and also to mine many of the more recently developed ore blocks by the latter method. The necessity for filling was due primarily to the structure of the ore blocks, the character of the walls and possible excessive dilution, but was influenced also by the grade of the ore-block and by the fact that cleaner mining can be carried out by cut-and-fill stoping.The comparatively few cut-and-fill stopes in operation prior to 1940 had been filled mainly with waste rock from development work, but as the amount of this material available, or likely to become available, would have been wholly inadequate for future operations, it was proposed to construct a system of passes to supply filling material from the surface.Owing to the distribution of the stopes, no central pass or system of passes could be devised which would service all the stopes satisfactorily.However, work was commenced on two passes, one designed to service the cut-and-fill stopes in the Eastern Section of the mine, and another to service those in the Western Section. It was realised that these passes could serve only a small proportion of the total number of Stopes (Figs. 1 and 2). During the progress of this work experiments were undertaken to test the possibility of using filtered tailings underground as an adjunct to the above scheme, but for various reasons these were only partially completed.Early in 1942 it was suggested by the Mill Superintendent that an attempt be made to fill with wet classified flotation tailings as practised at Mt. Lyell in Tasmania and at the Triton Mine at Reedy, West Australia. For the purpose of testing this, an experimental stope was prepared on the 309-ft. level, "X" Lode. This was 100 feet long and averaged 4 feet in width. Water-tight rearings were built at each end of the stope and waste rock fill was spread to a height of 6 to 8 feet above the timber. Used filter cloths were laid on top of the fill and brought a few feet, up the walls of the stope. A two-inch victaulic drainage line was then placed in position, the end passing through a hole in one of the bearings and thence to a sump. In the central portion of the stope two vertical pipes were brought up from this line. These were bored with one-inch holes staggered on opposite sides of the pipe, the vertical interval between each hole being one inch. The holes were then stopped with...

Jan 1, 1945

By Ruilin Yang

"Blast vibrations are essentially a strain/stress wave propagating in rock or structures inthe vicinity of a blast. However, blast vibration has always been quantified in terms ofpeak particle velocity (PPV) or acceleration (PPA), and a meaningful relationshipbetween blast vibration and strain/stress has not been established. The determination ofthe dynamic strain from blast vibration may improve quantification of blast damage andselection of a blast vibration limit for critical structures or high walls. Dynamic strainrelates to rock mechanics or material strength more directly than peak particle velocity(PPV). This paper documents a method to calculate the three-dimensional dynamic straintensor from recorded blast vibration signals. The method is based on determination of thedisplacement gradient at a point of interest for each time instance during the vibrationduration. The method to calculate dynamic strain is applicable to generic seismicwaveforms including near and far field blast vibration from a production blast withmultiple blast holes. In order to minimize measurement errors the specifications of thespacing between monitors and the sampling frequency of the vibration recording aredescribed."

Jan 1, 2012

A short account is given of the theory and practice of determining the true U3O8 content of ore samples by the determination of the beta and gamma activities separately, using the method of Eichholz and his associates.It is shown that, despite the variation of sample activity without change in U3O8 content, the true U3O8 value can still be found.Thorium can be determined simultaneously if this element is also present.

Jan 1, 1957

By Claude Deveau

"Studies on the performance of Falcon batch type concentrators treating ultrafine tantalum at Tanco have revealed that very fine heavy minerals are concentrated within certain areas of the concentrate bed. This information led to the design of a bowl which would allow entrapped lighter low grade particles to escape while providing more space for heavier particles to be recovered in the bed.Numerous tests were then completed with a modified batch-type and non-fluidized Falcon bowl in which the diameter of the discharge lip was adjusted downward manually in steps. This allowed for the gradual building of a higher grade concentrate bed.This work ultimately led to the design of a new Falcon with an automated continuously variable lip. In April 2005, Tanco commissioned the first Falcon UF600.This paper will discuss laboratory scale results and also plant performance of the Falcon’s UF technology.INTRODUCTIONTantalum Mining Corporation of Canada, also known as Tanco, is a wholly owned subsidiary of Cabot Corporation based in Boston, Mass. Operating since 1969, the underground highly mechanized room and pillar operation produces tantalum, lithium and cesium minerals and is located a 2 hour drive east-northeast of Winnipeg Manitoba, Canada.At Tanco, tantalum is recovered using conventional gravity concentration, enhanced gravity concentration and flotation. This paper will discuss how the need for improved equipment to treat very fine tantalum particles was filled by a machine which was modified to the point of creating a completely new technology.In November 2003, Tanco began the investigation for the potential use of a high g-force smooth walled concentrator for treating ultra fine tantalum produced by its flotation circuit. Until then, the tantalum flotation concentrate had been treated by a circuit which consisted of a Mozley Multi-Gravity Separator 902 (MGS), a Mozley MGS 900 and a Bartles cross belt concentrator. Through QemScan analysis, it was found that the majority of the losses from this circuit were of an extremely fine nature which exceeded the recovery limits of equipment on hand. Mean particle size of the tantalum losses was less than 10 µm."

Jan 1, 2006

By D. Strachan

Installation of support in known poor ground intersections during reaming operations requires rapid access to stabilize the shaft wall and thus to prevent the loss of the shaft through scaling. This is especially relevant to shafts of long dimension where the duration from time of exposure to time of support installation is lengthy This paper deals with the innovative methodology employed at Harmony?s No. 8 Shaft 17/24 level sub ventilation shaft to rapidly support a shale intersection between 23 and 24 Level by employing a single deck stage suspended from the reamer head by means of Skyjack winches.

Jan 1, 2009

By Gupta R. C

Syria has about 500 million ton deposit of minerals having 34 per cent iron content with alumina and silica as major impurities. Efforts were made to see the feasibility of concentration by four different methods involving washing, high intensity magnetic separation, reduction roasting and magnetic separation and acid leaching technique. It was observed that the reduction roasting with magnetic separation yields a concentrate with high iron (62.3 per cent) content without requiring water which is a scarce raw material in the region. The paper concludes that the detailed study may be made following this route to optimise the process Parameters.

Jan 1, 1999

By W. C. Phalen

The production of salt in the United States divides itself at the outset into two distinct classes…

Jan 1, 1915

By T. O. Hagan

Analyses of accident records show that a better understanding of very basic strata control principles and practices, by production personnel, will improve worker safety. Workers, lack of knowledge, with respect to aspects of strata control, increases their exposure to such strata control risks. The primary objective of the Safety in Mines Research Advisory Committee (SIMRAC) project 02 02 07 was to develop tools for the transfer of strata control knowledge. Four such tools were developed, three of which focused on illiterate underground mine team members who are not yet able to take advantage of the Mining Qualifications Authority (MQA) learning process (see project outcomes 2, 3 and 4 below). The tools were designed to equip these workers with sufficient knowledge and ability to work safely underground until such time as they can take advantage of the MQA system. Project outcomes: 1 A four-minute video using animation to illustrate the causes and prevention of falls of roof in South African collieries. 2 Software to demonstrate the capability of reconstructing, interactively, accident scenes and actions that have taken place underground in stopes. 3 A strata control bridging course for illiterate mine team workers. 4 Small-scale wooden models that will be used to design life-size mock-up facilities to assist with the above mentioned bridging course. 5 Workshops and presentations to demonstrate the outcomes 1to 4 above.

Jan 1, 2005

By C. E. Melbye

A serious problem confronted the city of Gunnison early in 1958 in that, for a few months during each spring runoff, the water supply derived from the Gunnison River became polluted to an unsafe point. The city management had the choice of building a new filter plant to replace the old unworkable one or drilling wells to develop a ground water supply. The cost of a new filter plant was estimated at $180,000 compared to $50,000 for 6 wells, pumps, and additional water lines, hence their decision to attempt the development of sufficient ground water. Six wells at 300 gpm per well were estimated as necessary to handle the peak usage of 1800 gpm, compared to only 600 gpm winter usage. Although the water table is only about 7 feet below the surface, existing private wells drilled at random locations were producing much less than 300 gpm. The problem was to find sufficient quantities from about 6 wells. Since the presence of an ancient bedrock channel was suspected, which would be expected to localize greater quantities of water, the city of Gunnison authorized a resistivity survey to investigate bedrock topography below unconsolidated gravels. Survey results were highly satisfactory and led to the preparation of a fairly detailed bedrock contour map, Fig. 1. This map was used in selection of all well sites. The city of Gunnison is situated in a flat, broad, Quaternary gravel-filled valley (terrain dips south at 20 feet per mile) at the junction of the Gunnison River and Tomichi Creek. The valley, about 2-4 miles wide, is bordered by hills of Tertiary volcanics to the northwest, Cretaceous and Jurassic sediments to the north and northeast, and pre-Cambrian granite and gneiss to the south. One previous deep test well at the west end of the city hit pre-Cambrian granite at 496 feet, which, allowing for 40 feet of surface gravels, makes the older sedimentary section 456 feet thick. This section is probably all Jurassic Morrison formation, consisting of the Saltwash sandstone overlain by the much thicker section of Brushy Basin shales and mudstones. According to the driller's logs, each well was bottomed in what is believed to be Brushy Basin shale. FIELD PROCEDURE A standard Gish-Rooney type of resistivity apparatus was employed, which used 45-volt dry batteries as a direct-current power source. Applied voltages could be selected from 45 volts to a 270-volt maximum. Copper-coated steel stakes were employed as current electrodes and porous porcelain pots as potential electrodes to avoid possible polarization effects with direct current. The expanding Wenner electrode configuration was utilized for this investigation and measurements were made at 20 40, 60, 80, and 100-foot spacings,

Jan 1, 1961

By J. Searra, M. Aboagye

"For new mining projects or for medium- to long-term areas of existing mines, drilling data is invariably on a relatively large grid. Direct estimates for selective mining units (SMUs), and also for much larger block units, will then be smoothed due to the information effects and the high error variance.The difficulty is that ultimately, during mining, selection will be done on the basis of SMUs on the final close-spaced data grid (grade control), which will then be available, i.e. the actual selection will be more efficient, with fewer misclassifications. However, this ultimate mining position is unknown at the project feasibility stage and therefore has to be estimated. This estimation is required because any cash flow calculations made on the basis of the smoothed estimates will obviously misrepresent the overall economic value of the project, i.e. the average grade of blocks above cut-off will be underestimated and the tonnage overestimated for cut-off grades below the average grade of the orebody. Similarly, unsmoothed estimates will be conditionally biased and will give even worse results, particularly in local areas of short- and medium-term planning or mining.This paper presents a case study of indirect post-processing and proportional modelling of recoverable resources designed for mediumand long-term mine planning at the Gold Fields’ Tarkwa Mine in Ghana. The case study compares long-term indirect recoverable mineral resource estimates based on typical widely spaced feasibility data to the corresponding production grade control model as well as the mine production. The paper also proposes certain critical regression slope and kriging efficiency control limits to avoid inefficient medium- to longterm recoverable estimates, and highlights the danger of accepting block estimates that have a slope of regression less than 0.5."

Jan 1, 2015

The common approach of designing blasts on a trial and error basis is quickly coming to an end. When utilizing the full scale blast environment, trial and error can quickly become cost prohibitive and leaves much to be desired in terms of true blast diagnostics. In these situations testing is usually only continued until a perceived improvement is achieved and when the gross undesirables in blast results are removed. This does does not preclude, however, that further improvements of up to 100% or more can not be obtained.

Jan 1, 1991

The iron ore deposits of the Port Hedland district of North Western Australia are associated with band'ed sedimentary iron formations that form part of the local succession of folded and faulted Archaean volcanic and sedimentary rocks. The iron formations are regarded as the protore beds or sources of the iron which became concentrated by supergene processes to form commercial grade iron ore deposits.Iron oxide deposits occurring in situ within the protore beds are considered to be of residual-replacement origin, due to supergene leaching of gangue minerals and' deposition of secondary iron oxides in their place, Two types of deposit have been recognized. Lode deposits are deep lenses of massive hematite located adjacent to major faults. These deposits are thought to be very old and to have originated by supergene processes during the long period of erosion represented by the major unconformity between the Archaean rocks and the overlying Proterozoic beds. The other type, known as crust ore deposits, are shallow cappings of hematite and goethite on hills formed by the outcrops of steeply dipping protore beds. These deposits could have originated as far back as the early Mesozoic and it is possible that the ore-forming process is continuing at a slow rate at the present day.Deposits formed by erosion and re-deposition of material derived from pre-existing residual-type deposits are known as derived deposits. These include conglomerates and scree accumulations of various types and ages and pisolitic deposits formed by supergene leaching of transported detritus. Derived deposits range in age from early Proterozoic to Recent. The presence of pebble accumulatio,ns of lode-type hematite in the Proterozoic basal conglomerate provides good evidence that lode hematite deposits existed in pre-Proterozoic times.INTRODUCTIONThe existence of iron ore deposits in the Port Hedland district of Western Australia has been known since the beginning of the century, but little attention was paid to them untIl the 1930's, when the Commonwealth Aerial, Geological and Geophysical Survey of Northern Australia carried out investigations of most of the then known mining fields of the Northwest Division. The only iron...

Jan 1, 1964

By Hugo Cabrera-Real

This work investigated the chemical and mineralogical properties of CaO-SiO2-CrOx-CaF2- MgO slags. Synthetic slags were prepared and the effect of the slag basicity (CaO/SiO2) and MgO contents on the stability of the mineralogical species formed was analyzed. The morphology and composition of the slags were analyzed by XRD and SEM-EDS, whilst their chemical stability was evaluated by leaching with an aqueous acetic acid solution. It was found that in slags with CaO/SiO2 = 1, the main Cr-compound was MgCr2O4 spinel, which forms octahedron crystals. Small amounts of CaCr2O4 and CaCrO4 were also observed. It was found that increasing the slag basicity from 1 to 2 the compounds MgCr2O4 and CaCr2O4 were formed together with the Cr(V)-containing compound complex Ca5(CrO4)3F which forms hexagonal crystals. The results showed that the highest chromium concentration levels in the leaching liquors corresponded to slags with CaO/SiO2 = 2, probably owing to the formation of Ca5(CrO4)3F.

Jan 1, 2010

By Philip J. H. Ball

The new application and development of grout jacking processes has combined, over the last decade in particular, to provide a method by which the effects of new underground construction on superficial structures can be controlled to acceptable levels. This paper sets out the basic principles, processes and limitations of compensation grouting. It describes key elements of the philosophy and design and details the control systems required to perform satisfactorily. To illustrate the application, a case history is described for the construction of a shaft and tunnel within and beneath the prestigious structure of Harrods in London.

Jan 1, 2000

By D. Harrington

The record of fatalities from mine explosions in the United States during the past 3 years has been the best in the history of the mining industry. During these 3 fiscal years, mine explosions have resulted in an average of 4I0 deaths per year, as compared with an average of 153 deaths per year for the preceding; 5 years; an average of 542 deaths per year for the 3-year period 1907-09, inclusive, just before the organization of the U. S. Bureau of Mines; and a yearly average of 265 deaths per year for the 20-year period prior to 1929. This remarkable reduction in deaths from mine explosions demonstrates clearly that mine explosions can be controlled; in fact, they can be prevented when or if the mining people of the United States see fit to take the readily available precautions necessary to bring about this desirable objective. Several large coal-producing States, which in the past have had numerous disastrous explosions, have been free from such disasters for continuous periods of as much as 6 years or even longer. The bituminous mines of Pennsylvania, the largest coal-producing State, give a good example of what can be done to prevent explosions; this State has had only one major explosion (and it resulted in 7 fatalities) during the past 6 years, and no explosion occurred in the several hundred bituminous-coal mines of the State during the past fiscal year. This is a truly remarkable record when compared with past performance in any year in the operation of coal mines in Pennsylvania.

Jan 1, 1936

By Georgene Renner, William R. Yernberg, Steve Kral

Allmand exhibited its LSC 100Light Sequence Commander, the mining industry’s first automatic lighting and command control system. The system is available with all of Allmand’s portable light towers. The LSC100 uses a preset photocell sensor that allows the light tower to be automatically turned on or off. At dusk, the sensor engages the power unit and then activates the light. At dawn, the sensor automatically shuts off the light. The unit also features an eight-event digital timer that allows eight separate sequences daily. The LSC100’s sequenced light control ensures that the engine is started before the lights are turned on or off. This prevents possible generator damage that can occur if the unit is powered down under load. Also, a low-fuel shutdown sequence helps protect the generator from damage by automatically shutting down the unit when the fuel level reaches 10 percent. And the LSC100’s smart circuitry senses engine water temperature during startup, determines the glow-plug time requirement and schedules repeat intervals, if necessary, to start the diesel engine.

Jan 1, 2004

By K S. Smith

Mineral-deposit geology, geochemical processes, and biogeochemical processes are fundamental controls on the environmental conditions that exist naturally in mineralised areas prior to mining, and that result from mining and mineral processing. Input from economic geologists and geochemists is therefore crucial to effectively predict, assess, mitigate, and remediate the environmental effects of mineral-resource development. Recent open pit gold mining at Summitville, Colorado , has received intense public scrutiny for a variety of environmental problems, most important of which has been extreme acid drainage. Now a Superfund environmental cleanup site, Summitville exemplifies how economic geology and geochemistry principles: 1. could have been better utilized to first predict and minimise the environmental problems, and 2. can now be used to optimize the environmental cleanup.

Jan 1, 1995

Recent advances in GPS, machine guidance technology and telemetry allow an unprecedented level of control of surface mining operations. GPS technology can now locate the bucket of a shovel or the blade of a dozer within 50mm (2 inches).Some of the outcomes possible are: precise selective mining – even when the ore is visually indistinguishable from waste: tracking grade and tonnage of every ore parcel through the mine: real time productivity monitoring: detailed post accident safety analysis: tracking the movements of every piece of equipment. This paper will consider the contribution that GPS based machine control systems can make to ensuring that surface mining projects deliver the outcomes promised in the feasibility studies. Case studies of installations are presented.

Jan 1, 2004

By Earl T. Hayes

[This work represent a continuation of the efforts of the Metallurgical Division of the Bureau of Mines to ascertain and apply knowledge of miner physics to processes metallurgy.]

Jan 1, 1941