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By J. B. Boisvert, W. Board, C. R. Mooney

"Traditional geostatistical modelling methods are difficult to apply to heavy-tailed deposits because the extreme positive skew of the grade distribution leads to bias. The focus here is on an innovative method of modelling the high-grade population by conditionally simulating discrete volumes (nuggets) of gold with marked Poisson and Cox processes. Capping and other ad-hoc manipulation of the assay data is not required; however, an intensity map for the point processes is required. The method is demonstrated on a dataset from an epithermal deposit and demonstrates an improvement in reducing smearing and controlling the skew of the grade distribution.RÉSUMÉ Les méthodes traditionnelles de modélisation géostatistique sont difficiles à appliquer dans des gisements dont la distribution de la teneur est à queue lourde car l’extrême asymétrie positive de la distribution de la teneur génère des biais. Dans le présent article, l’accent est mis sur une méthode novatrice de modélisation de la population à haute teneur par la simulation conditionnelle des volumes discrets d’or (pépites) au moyen de procédés marqués de Poisson et de Cox. La limite d’utilisation et d’autres manipulations ad hoc des données ne sont pas requises; toutefois, il faut une carte des intensités pour le processus ponctuel. La méthode est démontrée sur un ensemble de données d’essais provenant d’un gisement épithermal et elle montre une amélioration dans le lissage du flou et dans le contrôle de l’asymétrie de la distribution de la teneur."

Jan 1, 2015

By S. K. Kawatra

Many mineral oxide and multi-component oxide (basalt) specimens break down into powders upon expo-sure to sodium vapor at elevated temperatures for extended times. This paper examines several possible mechanisms of oxide breakage by sodium vapor, both experimentally and from a thermodynamic viewpoint. The oxides for which reduction by sodium was thermo-dynamically favorable all exhibited some degree of fragmentation. The oxides which were not favorable for reduction by sodium did not exhibit fragmentation, with the exception of rutile, a titanium oxide. The rutile fragmentation was caused by the reduction of iron that was in solid solution in the rutile crystal structure.

Jan 1, 1995

By Pathik Deb Mallik, Shyamal K. Mitra, Rajiv Kishore, Shuvranshu Rout, Manos De

"This paper presents a case study on the design and construction of a deep underground pit structure constructed inside almost a century old existing plant building. The complexity and challenge for the design and construction lay in executing the work in a difficult subsoil condition especially the presence of deep mica schist. The limited space availability in the existing plant for construction work without hampering regular production in other adjoining areas of the plant made the execution more challenging. Experience with difficult subsoil and proximity to old foundations entailed a non-conventional engineering approach while ensuring complete safety in spite of maintaining the normal operation.INTRODUCTIONTata Steel Processing and Distribution Limited (TSPDL) is a subsidiary unit of Tata Steel Limited (TSL) having a CR processing facility inside the premises of Tata Steel Limited. TSPDL intended to install equipment for a new slitting line inside the existing shed including construction of very deep structure called “loop pit” where the strips from cut CR sheets collect in the form of loops and are recovered as scrap. The entire plant is located within the shed of existing plant. The construction of all foundations including the loop pit is to be executed in the limited area without disturbance to normal production work in balance areas of the plant and also maintain safety and integrity of existing structures.The existing shed is an old structure constructed approximately 80 years ago. The building column foundations are gravity type design of brick masonry supporting only the vertical load from the columns. This type of foundation designed with no eccentricity of loading provides no allowance for implementing any foundation stabilizing design. The present project required civil construction for the new equipment foundations safely within this area."

Jan 1, 2015

By Paul M. Tyler

ROUGHLY one-half the value of mineral products at mines or quarries must be spent for wages. In view of the steady increase in hourly wages that continued for several decades prior to the onslaught of the recent depression, it is perhaps surprising to discover that labor's share of the gross proceeds of the mining and quarrying industries of the United States declined to 46.8 per cent in 1929, compared with 52.2 per cent in 1919 and 53.2 per cent in 1909. The actual percentages vary in different branches of the industry and in different localities but the downward trend is unmistakable. For the period 1909 to 1919 it was quite marked in every industry and from 1919 to 1929 it was apparent in all but six: namely, gold and silver lode mining, placer gold mining, crude gypsum production, marble quarrying, asbestos production, and fluorspar Tninino mining

Jan 1, 1933

By Chuansheng Luo

If lead-zinc ores have high oxidation rate, separation of lead and zinc is very difficult. This paper studied the technology of preferential flotation by the coarse grinding and re-grinding. The lead concentrate grade is 51.40% and the lead recovery is 62.83% when feed grades Pb 1.74% and Zn 6.46% with oxidation rate being 13.75%. At same time, the zinc concentrate grade is 50.07% and its recovery is 90.01%.

Sep 1, 2012

By Abhirami B., V. Balakumar

Piled raft foundation system is an intelligent geotechnical concept, developed towards reducing the settlement of the raft and the footings by providing pile elements below the raft or footings, as the case maybe. Although a large volume of works has been done on the behaviour of piled rafts by observational studies, the effect of construction methodologies such as deep excavations, the installation methodologies used for piling etc appear to have not been covered adequately. This paper discusses the effect of deep excavations, pile installation techniques and the effect of adding structural elements, based on the data available from published literatures. Based on this study, the performance of the piled raft monitored by the author has been revisited and the results of such a study are discussed.

Nov 1, 2022

By Adrien Berton

FOR nearly a century, the Corocoro deposit has been renowned among geologists from the fact that it shares with the Lake Superior deposits of the United States the distinction of being the only important copper districts where native copper is worked commercially. The Corocoro district, named after the city of Corocoro, the capital of the Province of Pacajes (Department of La Paz, Bolivia) is situated towards the western edge of the Bolivian high plateau, at an altitude of a little over 13,000 ft. The most interesting part of the district is that immediately surrounding the city of Corocoro, at a distance, by railway, of 65 miles from La Paz and 210 miles to the Chilean port of Arica on the Pacific Coast. The climate of the region is that of the semi-desert, dry and relatively cold, with big differences of temperature between day and night. The rainy season begins in December and ends in March. The cupriferous lodes of Corocoro have not attracted as much interest as the silver mines of Potosi but they have been known for a long time. In the precolonial period the Indians were using the charquis, or natural native copper sheets, to make small brass objects, and the beautiful pale green brochantite of the outcrops as a source of green pigments. During the colonial period, the oxidized ores of the outcrops were worked for copper, which was used by the mint at Potosi for making currency. The native copper ores were neglected because the Spanish miners were at a loss how to concentrate and smelt them. About 1830, work by rudimentary processes, which were improved little by little, was begun on the native copper ores. The total production of native copper in the following hundred years amounted to 100,000 tons. This native copper, which was remarkably pure, was much appreciated on the European markets before the introduction of electrolytic copper. It was useful for making special ornamental brass or bronze and the granular concentrates of native copper, called barrilla, containing 80 to 85 per cent copper were suitable for making copper sulfate by direct oxidation and subsequent leaching with sulfuric acid.

Jan 1, 1936

By A. Moharana

A massive slide at Bingham Canyon wiped out a side of the pit and covered the main haul road in and out of the pit. All pre-slide mine designs and schedules were no longer valid. New designs and schedules needed to be developed quickly to provide management with information regarding the immediate post-slide production potential and the time needed to ramp back up to full production. At the time of the slide, an effort was already underway to convert Bingham?s in-house Medium Term Scheduling Process to MineSight®?s Schedule Optimizer (MSSO). One of the main reasons for doing this was to reduce the time needed to produce Medium Term Schedules at Bingham, which involves a complex shovel-based scheduling approach with shovel productivities based on shovel type and the types of mining cuts to which the shovel is assigned over each planning period. The objective of the schedule was to maximize shovel usage, satisfy mill feed requirements of four SAG mills with variable milling rates, and have flexibility in setting truck constraints. This paper will describe how the new MSSO-based mine scheduling process met the challenge of producing new schedules for Bingham in a minimal amount of time.

Feb 23, 2014

By F. Chachula, A. Molinaro

"Sulphide mineral flotation operations continuously strive for a balance between mineralogy, mineral liberation, circuit conditions and reagent solutions to maximize the production rate and recovery of payable metals. The Taseko Gibraltar copper – molybdenum mill operations underwent an extensive project focusing on the fundamentals to identify the effects of process conditions and mineral liberation to improve the bulk circuit copper – molybdenum recovery efficiencies in the bulk flotation circuits. This discussion will provide process data that demonstrates; 1) fundamental relationship between mineral liberation to recovery and grade, 2) flotation circuit condition testing and optimization, 3) reagent combinations resulting in efficient/economical mineral recovery, and 4) the development of a xanthate free reagent solution. The data presented and discussed will also touch on flotation parameters including pH, retention time, kinetics and the effect on bulk circuit recovery performance.INTRODUCTION Taseko's is the owner (75%) and operator of the Gibraltar copper-molybdenum mine, located in south-central British Columbia, the second largest open pit copper mine in Canada and the largest employer in the Cariboo region. Taseko restarted Gibraltar in 2004. From 2006 until 2012, the company invested ~$700 million to expand and modernize the operation which was originally scheduled for demolition when the company acquired it in 1999. In the spring of 2011, construction commenced for Gibraltar Development Plan 3 (GDP3). GDP3 included the construction of a standalone 30,000 ton per day concentrator, built adjacent to the existing 55,000 ton per day facility. The new design capacity of Gibraltar was designed to be 85,000 tons per day. An integral part of the project was a new molybdenum recovery facility. In addition to the new concentrator, the mining fleet was upgraded with a new mining shovel, production drill and ten haul trucks (Taseko, May 2015). In May of 2015, the Company completed an updated mine plan for Gibraltar featuring a 50% decrease in strip ratio. This new mine plan was a result of a detailed, six-month engineering study and forms the basis of an updated NI 43-101 compliant reserve (Taseko Announces Improved Economics At Its Gibraltar Copper Mine, 2015). The new mine plan took into account lower milling costs as a result of the modernized processing facilities (Taseko, May 2015)."

Jan 1, 2018

By Ana Maria Gontijo Figueiredo

Muitos dispositivos biomecânicos têm sido produzidos com ligas superelásticas (SE) de NiTi. Na maioria das aplicações, o material é submetido a solicitações mecânicas cíclicas, tornando seu comportamento sob fadiga um parâmetro importante. Neste trabalho são apresentados resultados de ensaios de fadiga por flexão rotativa de um fio SE, ensaiado a seis temperaturas diferentes, sob amplitudes de deformação (?a) variando de 1% a 12%. As curvas mostram que a vida em fadiga do material na fase martensítica estável (ME) é cerca de 100x maior do que na fase austenítica estável (AE). A curva do fio SE se aproxima da curva do fio AE para pequenas ?a e, com o seu aumento, se aproxima da curva do fio ME quando ?a aumenta. As superfícies de fratura obtidas foram observadas ao microscópio eletrônico de varredura e foram calculadas as áreas correspondentes à fratura por fadiga (af). Os resultados mostram que, para o fio nas fases AE e ME, af decresce continuamente com o aumento da ?a. Para o caso do fio SE, af permanece relativamente constante para valores intermediários de amplitude de deformação (2% a 8%). Para uma mesma deformação, af cresce com a redução da temperatura, com o consequente aumento do número de ciclos para falha.

Aug 8, 2018

By J. A. Ruppert, P. M. Sullivan

A study was made of filtration techniques for recovering the major part of the tin contained in iron - tin alloys known as hardhead . Special smallscale filtering apparatus and a three - stage cyclic process were developed . Eighty- seven percent of the tin contained in an alloy of 82 percent tin and 17 percent iron was recovered as pure metal by pressing at 975° C followed by a second pressing at 800 ° C and a final filtering at 250 ° C. Small amounts of Sb , Cu , and Fe impurities were removed by adding Al to the molten product and performing another filtration at 250 ° C.

Jan 1, 1964

This Bureau of Mines report on underground mine communications addresses methods and equipment to meet the communication requirements of working sections and places of coal and metal-nonmetal mines. A review of the status of trapped miner detection is also presented.

Jan 1, 1977

By S. Usui

In a previous article1 the methyl stretching vibrations for a series of xanthates and amines were reported, and the frequency of the methyl stretching vibrations in a homologous series of the alkyl compounds were shown to decrease exponentially with chain length and approach a limiting value corresponding to that of saturated hydrocarbon beyond six or seven carbons. These observations were explained quantitatively by the theory of Goto and Takenaka2 who proposed an equation relating the frequency shifts to the inductive effect of polar groups. As a result, the alkyl groups in the shorter chain heteropolar compounds were interpreted as becoming somewhat polar, and a good correlation was observed between the CH3-stretching frequencies and such surface chemistry parameters as contact angle, surface tension lowering, solubility, and critical micelle concentration" The substitution of fluorine atoms, the most electronegative of all atoms, for the hydrogen atoms in alkyl groups was expected to reverse the direction of the inductive effect within a heteropolar molecule, and its effect on the C-F stretching frequency shifts and on some surface chemical properties became of interest. In a recent study the C-F stretching frequencies of a series of normal perfluorocarboxylic acids and a few 1,1' -dihydroperfluoro alcohols were determined as a function of chain length and the results were compared with the corresponding hydrocarbon analogs. Furthermore, the nature of the induced polarity in the hydrocarbon and fluorocarbon groups was investigated through surface potential measurements at the interfaces of air-aqueous solutions of normal butyl alcohol and of l,l'-dihydroperfluorobutyl alcohol and through differential capacity and electrocapillary measurements at the interfaces of mercury-aqueous solutions containing the above two alcohols. Experimental Normal perfluorocarboxylic acids and 1,1' -dihydroperfluoro alcohols were provided through the courtesy of the 3M Company, St. Paul, Minnesota. Normal butyl alcohol was purchased from Distillation Product Industries, Rochester, New York. A Perkin-Elmer Model 621 infrared spectrophotometer was used to investigate the spectra in the frequency region of 1200 to 1270 cm-l with frequency scale

Jan 1, 1971

By Celine Y. Zhang, Chloe J. Feng, Charles Q. Jia, Donald W. Kirk

Oil sands petroleum coke (OSPC) is a by-product of coking - a high-temperature process that converts the mined bitumen to the synthetic crude oil (SCO). For every barrel of the SCO produced, about 20 kg of OSPC are generated. Over 70 million metric tons of OSPC have been produced and stockpiled as a result of the development of oil sands industry in the past few decades. Unlike conventional petroleum coke, OSPC has uniquely high impurity contents, particularly sulphur (~ 7 wt%) and metals (e.g. vanadium at ~0.15 wt%), which has hindered its large-scale applications as a solid fuel. Vanadium is a valuable metal that is widely used as an alloy for strengthening steels. The stockpiled OSPC contains about 100,000 tons of vanadium, while the world’s production in 2013 was only 75,600 tons. At the current price of $25US/kg, the OSPC-bound vanadium represents a total value of $2.5 billion US dollars. In this work, we investigate the technical feasibility of extracting vanadium from OSPC. The work focuses on the characterization of vanadium in OSPC and the conditions for effective extraction of vanadium from the OSPC.

Jan 1, 2015

A methodology has been developed and demonstrated to be effective in reclaiming surface-mined land for a forestry post-mining land use. The forestry reclamation approach (FRA) has been applied, almost exclusively, to flat or gently rolling surfaces. One of the primary steps in the FRA is to loosely grade the top 1.22 m (4 ft) of soil or substitute root growth medium to avoid excessive compaction. Concern has been expressed by regulators and the public that loose grading on steep slopes (i.e., greater than 23°) could lead to slope failures, which is one of the issues that the Surface Mining Control and Reclamation Act of 1977 (SMCRA) sought to correct. A field investigation was conducted at a steep-slope contour operation in eastern Kentucky to test the applicability of FRA in this setting. Final grading was performed according to FRA standards. The surface consisted of two distinct substitute rooting media. One was unweathered gray sandstone and the other was a combination of gray sandstone, brown sandstone, and topsoil. A variety of native hardwoods was planted following the FRA guidelines. The slope was instrumented with 70 survey monuments to monitor for mass movement. The reclaimed spoil was also characterized using bulk density and penetrometer resistance methods. The characteristics of both spoils are similar to those observed on flat to rolling surfaces where the FRA has been used and, after one year, approximately 70% of the trees had survived. During this first phase of investigation, there has been no major mass movement of the slope and slope stability analysis indicates that the application of the FRA has little impact on the overall stability of the slope. Mining Engineering, 2011, Vol. 63, No. 12, pp. 55-62. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By J. H. C. Scrimgeour, T. Toong, R. E. Hamilton

"The principles involved in the use and application of mathematical models as an aid to the development of advanced process control computer systems are described briefly. This is followed by a brief survey of known models of this kind for the simulation of mining industry processes.The main part of the paper describes a dynamic model of the flotation process developed by Canadian General Electric. Using flotation rate constants for each species of mineral and gangue, the model provides a numerical solution of the differential equations describing cell behaviour. The cell mode] is used repeatedly as a subroutine in the •over-all-plant model. The features of the cell and plant models are described.Simulation runs from the plant model show stream .assays and other indications of plant behaviour printed typically in 1-to 10-minute steps for several hours of •Operation following typical disturbances such as changes in feed rate or reagent addition rate. The simulation can :Show expected behaviour for both uncontrolled and computer-controlled plants."

Jan 1, 1970

By M. Z. Emad, A. Hassan, M. A. Raza, M. U. Khan, S. A. Saki

Digital modelling of a surface is crucial for Earth science and mining applications for many reasons. These days, high-tech digital representations are used to produce a high-fidelity topographic surface in the form of a digital terrain model (DTM). DTMs are created from 2D data-points collected by a variety of techniques such as traditional ground surveying, image processing, LiDAR, radar, and global positioning systems. At the points for which data is not available, the heights need to be interpolated or extrapolated from the points with measured elevations. There are several interpolation/extrapolation techniques available, which may be categorized based on criteria such as area size, accuracy or exactness of the surface, smoothness, continuity, and preciseness. In this paper we examine these DTM production methods and highlight their distinctive characteristics. Real data from a mine site is used, as a case study, to create DTMs using various interpolation techniques in Surfer® software. The significant variation in the resulting DTMs demonstrates that developing a DTM is not straightforward and it is important to choose the method carefully because the outcomes depend on the interpolation techniques used. In mining instances, where volume estimations are based on the produced DTM, this can have a significant impact. For our data-set, the natural neighbour interpolation method made the best predictions (R2 = 0.969, β = 0.98, P < 0.0001).

Feb 6, 2023

By D. M. S. Bhatia

The intimate association of iron formation and massive sulfide deposits has been documented by many investigators (McAllister, 1960; Hutchinson, 1972). In a classic example of such an association four distinct facies (oxide, carbonate, silicate, and sulfide) were identified in an Algoma type iron formation occurring in Paleozoic rocks, but exhibiting physical features (banding) and chemical composition (SiO2 + A1203 + Fe2O3) typical of Precambrian iron formations. The geochemical variation of the iron formation was studied by analyzing 62 samples for Si, Al, Fe, P, S, and CO2. Following a model proposed by James (1954), the geochemical and mineralogical variation of the iron formation can be used as an excellent tool for the exploration of massive sulfide deposits.

Jan 1, 1981

By Edmund S. Leaver, A. P. Towne, Jesse A. Woolf

Part of the work of the Precious Metals Section is to conduct oretesting experiments on ores selected as representative of various mining districts or areas . The projects are authorized by the Metallurgical Division , and only those ores in which gold and silver or gold or silver constitute an essential part of the total values are assigned to the Precious Metals Section . Such ores include those containing the precious metals only as commercially important ingredients , as well as those containing base metals such as copper , lead , and zinc along with the gold and silver . In many instances the "ore " may be a tailing product of a grade good enough to warrant retreatment , or a concentrate for which it is desirable to develop a method of treatment to avoid the expense of shipment to a smelter . It is evident that in general the greater part of this ore - testing work is done according to standard testing procedure , such as cyanidation, amalgamation, gravity - concentration , and flotation , or a combination of these methods . The standard methods of conducting such tests have been outlined in previous reports of ore - testing studies . However , since the inauguration of this oretesting program 6 years ago , the ores submitted under authorization have become increasingly more refractory to simple methods of treatment. Consequently, a considerable number of the projects completed during the fiscal year 1941 have required an unusual amount of work and in some instances have developed into real research problems . For such ores more complete microscopic and spectroscopic examinations and more complete chemical analyses

Feb 1, 1942

By J. Jerome MacDonald, Stephen B. Flewelling

"In the base metals industry of today, operations required to continuously improve productivity and reduce unit production costs. Consistent with these goals is the improvement of the muck haulage cycle from open stopes with the No. 12 Mine.Existing haulage from open stopes occurs with LHD units experience at Brunswick indicates that LHD units have a higher unit cost per tonne mucked than loader-truck combinations when the haulage exceeds approximately 150 m.The reintroduction of open stoping at Brunswick made existing loader-truck combinations unsuitable. It was recognized that application of recent continuous loading technology could potentially result in significant unit cost savings and productivity increases.A review of the technology resulted in the testing of the Voest Alpine AL60 loader in the open stopes located on the 1000m Le vel. Testing began in January 1988 and finished in late November 1988. The test will provide experience as well as quantified production and maintenenace parameters f or the purpose of quantifying production unit costs and system productivity, ultimately resulting in a decision to further utilize or not utilize the loader as a primarymucking unit at Brunswick .INTRODUCTIONBrunswick Mining and Smelting Corporation Ltd. produces approximately 10500 tonnes per day from the No. 12Mine located 35 km southwest of Bathurst, New Brunswick Mining is the largest (single mine) producer of zinc in the world having mined over 52 million tonnes since 1964. Many years of production still remain with proven and probable reserves in excess of 90 million tonnes. Reserves grade at an average of 3.65% Pb. 8.99070 Zn, 99g/mt Ag and 0.32% Cu . The operation employs 1446 people with approximately 800underground including operations and maintenance staff.In the No. 12 Mine two major mining methods are presently utilized . The primary method is Mechanized Cut and Fill (MCF) accounting for approximately 6500 tonnes per day from four major areas. The remaining 4000 tonnes per day is produced from open stopes with the majority of 2800 tonnes per day being produced by the 1000 level.The 1000Level contains 30 million tonnes segmented into open stope blocks 30 m high, 15m and 30 m on strike , with a transverse width of 10m to 50 m (Fig. I). Stopes are organized on a primary secondary stope arrangement along strike. Primary stopes are undercut and overcut full size with the back fully cablebolted. All stope and lateral development is driven 4.0 m high. All stopes to date are flat bottom (Fig. 2). Primary stopes are filled with cemented rock- fill , secondaries with conventional rockfill, Haulage from the stopes is primarily with 8-yard LHD units ; mucking is approximately 50% conventional and 50% remote. Haul distance to date has averaged approximately 150m with current stope haul distances of approximately 300m. Haulage is presently to a small jaw crusher situated on the 1000 Level. From August 1989on, haulage will be to a set of ore passes feeding to a large gyratory crusher situated on the 1200 Level. Start up of the gyratory crusher corresponds to an increase in tonnage from 1000 Level to 4100 tonnes per day."

Jan 1, 1989