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By M Furche, U Noell, C Grissemann, J A. Meima, T Graupner, A Romero-Baena

The mining residues at the abandoned copper mine site Pe±a de Hierro, located at the headwaters of the Rio Tinto, contribute substantially to the pollution of the river with high loads of Fe, As, Pb, Zn and Cu. The pH of the outflow ranges from 0.5 to 2.4 in the dry and wet season, respectively. One heap composed of alternating layers, which were deposited parallel to the slope, was investigated in detail. Unsorted blocky to fine materials including gossan material, pyritic volcanics, ashes from pyrite combustion and slate were observed here. The top of the heap has a gentle slope and a hill contouring channel-rip morphology. The initially rugged surface was smoothed by heavy rainfalls filling up the pores of the blocky material with fines. These fines are capable of storing the water for a prolonged time, providing an extended reaction time close to surface in a dry climate at extremely low pH conditions (one to four). All minerals, pyrite, mica, barite and even quartz (probably due to F released from dissolved mica) have been digested and silica gel precipitates have formed a stable and quasi impermeable 100 ¦m layer with very low porosity (<5 area per cent, estimated using scanning electron microscopy (SEM) imaging). The silica layer itself is covered by Fe-oxy-hydroxide (ie FeOOH) coating (10 ¦m) and seals a 1 - 5 mm thick stable hardpan. This hardpan covers the channels and part of the rips almost entirely, guiding the rainwater subhorizontally towards slopes and sinkholes. By geoelectrical measurements, a 3D-resistivity model of the internal structures and the bedrock relief underlying the heap was generated. Internal structures relate to lithological changes in a number of layers. Zones of low resistivity may be attributed to washed-in fines within the mega pore system, whilst zones of high resistivity close to the surface probably reflect the advanced stage of drying beneath aging hardpans. The water movement at the surface was investigated by an artificial precipitation experiment with monitoring of the subsequent changes in resistivities.

Jan 1, 2008

By Jon Sinnreich

Ensuring the accuracy of collected data during deep foundation static load tests is of paramount importance. Typically, pile head displacements are measured relative to a purpose-built reference system, which is assumed to be fixed. This study presents a simplified error analysis of this assumption, illustrates the potential magnitude of these errors, and proposes an improved method of pile head displacement monitoring.

Jan 1, 2009

By Oliver B. Hopkins

"WE HAVE patterned our lives on the things we take from under the earth's surface. Our civilization is built upon the ore from which we obtain our metals and the fuels which power the world as we know it.Today I should like to discuss with you a newcomer to the ancient mining industry. This lusty infant of which I speak is just a century old - the oil industry.While one doesn't commonly think of oil men as delvers in the earth, It was by sinking a shaft that the first oil was obtained commercially in Canada. Men sank a shaft in a ‘gum bed' in southwestern Ontario's Lambton county, not far from Petroilia, and distilled from the gum a burning oil That was just a hundred years ago. The gum was originally liquid petroleum which had seeped to the surface and lost most of its volatile components.Later, the miners dug down to •bed-rock and soon after they were not digging but were drilling wells, as they have been ever since. From the wells they obtained erode oil.What is crude oil? It is not an element like gold, silver or lead, •but a complex mixture of compounds. These compounds are made basically from two elements, carbon and hydrogen, and are called hydrocarbons (Figure 1).The remarkable ability of these. Two elements to combine in different ways gives crude oil its physical and chemical character. The lighter hydrocarbon compounds in it are gases, at normal temperature and pressure, and these are dissolved in the other, heavier compounds."

Jan 1, 1952

By O. H. Metzger

This is one of a series of papers being published by the Bureau of Mines on mining areas and districts in the Western states. It describes mining and milling practices in the vicinity of Wickenburg in Maricopa and Yavapai Counties, Ariz. ACKNOWLEDGMENTS The author acknowledges the aid and cooperation of the operators of the mines visited. Reports of geologists and engineers who previously visited the area were drawn upon freely. Individual acknowledgments are made in the text.

Jan 1, 1938

By D. Harrington

"Up to the last 10 or 15 years, responsibility for accidents in mines was generally, though not universally, placed upon the person or persons immediately involved. Present-day thought is rapidly veering toward holding the industry responsible for accidents, with ultimate payment of the bill by the consumer, if financial expenditure should be necessary. While it is undoubtedly correct in principle that responsibility for accidents in and around mines should be shouldered by the employer and while it is probable that as time passes the burden will become even more definitely than now that of the mining companies, on the other hand it is an undeniable fact that large numbers of accidents occur through acts of omission or of commission of some person, very frequently the victim of the accident being the offender.Out of about 3,000 persons killed every rear in our -mines and quarries, nearly half or approximately 1,500 of the fatalities are due to falls of overlying material or of persons, about 500 to haulage, about 350 to fires and explosions, about 125 to explosives, approximately the same number to electricity, and about 300 to various miscellaneous accidents.Generally the accidents from falls involve but one or two persons at a time, and the tendency is now as it always has been to charge the victim or possibly a coworker with the responsibility. Usually this sort of accident occurs at or near a working face (statistics indicate that about 80 per cent of fatalities from falls of roof or rib occur near the face), and as it is Generally agreed that it is the duty of the worker to keep his working place safe, the worker and especially the face worker is given the blame in case of accident."

Apr 1, 1930

By J. K. Afidenyo, J. Osei-Owusu

"The Obuasi Mine of AngloGold Ashanti Limited has been operating the world’s largest Biooxidation Plant at its Sulfide Treatment Plant (STP) in Ghana, using the Gencor Biox® technology since February 1994. The Biox® technology was preferred to other alternative methods of treating refractory sulfide ores such as roasting, pressure oxidation and nitric acid leaching due to among other reasons, its lower capital and operating costs, reduced technical risk, relatively benign environmental impact and its ease of operation and maintenance in a remote location.STP has since commissioning succeeded in operating this technology successfully but not without some operational problems. The Plant has seen a number of upgrades and modifications in its circuits which were motivated by cost, operational and throughput constraints.The objective of this paper is therefore to highlight the mine’s experience in the treatment of its complex carbonaceous refractory sulfide gold ores with emphasis on plant operations and improvements such as the Biox® reactors expansion, flotation concentrate upgrade project and neutralization circuit modifications. The Biox® Plant operating cost is also discussed.INTRODUCTIONThe Obuasi mine forms part of the AngloGold Ashanti Group of Gold Mines. It is located in the Adansi West District of the Republic of Ghana. The mine is primarily an underground operation, although some surface mining still takes place. Ore is processed by two main treatment plants: the Sulfide Treatment Plant (for underground ore) and the Tailings plant (for tailings reclamation operations). A third plant, the Oxide Plant, is used to batch-treat remnant opencast ore and stockpiles, of which there are adequate tonnages to keep the plant operational until 2008.Though reference is made in this paper to the Tailings and Oxide Treatment Plants, the main focus will be on the Sulfide Treatment Plant."

Jan 1, 2008

By S Hapugoda, A Poliakov, E Donskoi, L Lu

A significant amount of metallic iron in the world is produced in blast furnaces from iron ore pellets. To control the quality of pellets and to optimise pellet production, characterisation of both green and fired pellets is required. Optical image analysis (OIA) allows identification of different minerals, binder, remaining fluxes and porosity within pellets.For proper identification of the mineralogy, porosity and texture in pellets a high magnification is required, therefore each individual image covers only a very small portion of the pellet. At the same time the characterisation of pellets requires that the whole pellet is represented as a single object, so the size of the resulting overall image at high magnification can make it difficult to handle. A solution to this problem has been implemented within the CSIRO OIA package Mineral4 by combining images at different levels. Namely, to average out local irregularities, individual frames can be stitched during imaging into larger MosaiX images. Mineral4 further combines these MosaiX images into a single panorama image of the whole pellet.The proposed procedures allow the calculation of mineral and porosity spatial distributions, local gradients and abundance graphs based on the distance from the centre of the pellet. The ‘Pellets’ module of CSIRO OIA software also allows for characterisation of large irregularly shaped particles of lump ore and sinter.CITATION:Poliakov, A, Donskoi, E, Hapugoda, S and Lu, L, 2017. Optical image analysis of iron ore pellets and lumps using CSIRO software Mineral/Recognition, in Proceedings Iron Ore 2017, pp 583–592 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Fine Coal Evaluation by Gravity Methods

Sep 13, 2010

By Frederick C. Rhyner

This paper describes the design and construction of two high-capacity rock anchors to restrain a supplementary backstay for the Bear Mountain Bridge, which is a suspension bridge spanning the Hudson River about 40 miles north of New York City. The supplementary backstay was installed to relieve a portion of the tension in the southern main cable, which had been creeping in recent years. The two new rock anchors were 1,200 kip capacity each, installed at a batter to depths of 59 feet. This paper describes the subsurface investigation, group capacity analysis, installation and load testing. The rock anchors included strain gages connected to the monitoring system for the bridge. The paper describes the long term strain gage data which shows no change in stress distribution in either anchor.

Jan 1, 2010

Experimental Study of Ore Characterisation Methods for AG/SAG Mills Mining companies have long recognised the importance of ore breakage characterisation in design and optimisation of their crushing and grinding circuits. In one of the industry standard methods relevant to AG/SAG milling, ore is characterised using mainly high energy single impact tests. However recent DEM studies have suggested that breakage in AG/SAG mills is mainly due to low energy repetitive (or multiple) collisions rather than single high energy impacts. Hence a study was initiated at the JKMRC to investigate the behaviour of ores under such conditions. Carefully designed experiments have been performed using two laboratory mill sizes (0.6 m and 1.1 m diameter) to mimic the reported low energy repetitive impact breakage under low load conditions. The breakage characterisation parameters derived from standard high energy single impact tests on the same ores was then used to predict the low energy repetitive impact breakage. Significant bias was found in the simulations which clearly warranted further investigation. The extensive experimental program which followed employed three separate methods: the JKRBT (JK Rotary Breakage Tester) for high energy single impact and low energy repetitive impacts, gravity drops for low energy repetitive impacts, and laboratory mills to provide an extended number of low energy repetitive impacts. The breakage energies associated with these experiments were accurately measured with a high speed video camera. Two breakage indices, the degree of breakage (t10) and the breakage probability (S) were used to describe the breakage test results. This paper summarises the major results from this experimental study, which has facilitated the development of a new breakage characterization method relevant to AG/SAG mill modelling.

Sep 13, 2010

By Marisa Martins

Este trabalho aborda o processamento de rejeito proveniente do circuito de flotação de minério de ferro da mina de Cauê. A amostra utilizada no presente estudo apresentou teores médios de 27% de Fe, 59% de SiO2 e 1,4% de Al2O3. A concentração de hematita contida neste rejeito foi avaliada, utilizando-se flotação aniônica em meio ácido e na presença do ânion SiF6 2-, como depressor da ganga silicatada. De posse da caracterização granulométrica, química e mineralógica do rejeito, ensaios tecnológicos de flotação foram executados, objetivando a avaliação dos variados sistemas de reagentes. Diferentes dosagens dos depressores H2SiF6 e Na2SiF6 e ainda de três diferentes tipos de coletores aniônicos foram avaliados. Os melhores resultados foram alcançados pelos coletores do tipo ácido graxo e sulfonato de petróleo, os quais geraram concentrados contendo 66% de Fe e 4% de SiO2, e recuperações metalúrgicas de Fe de 59% e 71%, respectivamente.

Aug 16, 2017

By Rimas Pakalnis, Andrea M. Ouchi, Thomas M. Brady, Mary M. MacLaughlin, Cristian Caceres, Paul Hughes

A major focus of ground control research presently being conducted by the Geomechanics Group at the University of British Columbia, Canada, in conjunction with the National Institute for Occupational Safety and Health’s (NIOSH) Spokane Research Laboratory, is the development of design guidelines for underground mining within weak rock masses. The study expands upon the span design curve for man-entry operations and the stability graph for nonentry operations developed at UBC by extending the application to weak rock masses. The original database has been augmented by weak rock mass information from mines throughout the United States, Canada, Australia, Indonesia, and Europe. The common factor in all of these mines is the presence of a weak back and/or walls. This paper expands on the North American database and how the design curves have been employed at mining operations throughout the world. The definition of a weak rock mass for this study has been defined as having an RMR76 under 45% and/or a Q-value under 1.0.

Jan 5, 2007

By James A. Finch, Stéphanie Somot

"The self-heating facility developed at the Noranda Technology Centre [Rosenblum and coworkers, 2001; 1995] has now been established in the Department of Mining, Metals and Materials Engineering at McGill University. A research program into mechanisms has been initiated (with support now from four industrial partners under Camiro). The first investigation is into the role of pyrrhotite (Po), the most commonly suspected mineral to trigger self-heating. Following a standard experimental protocol, self-heating was assessed on samples of Po mixed with sand as an inert material. With increasing Po content, self heating progressively increased but, interestingly, the samples visually appeared less and less oxidized. A high Po content, it was hypothesized, may give a more reducing environment favouring formation of H2S. The presence of this gas could be significant as it has a high exothermic heat of reaction with oxygen. The system was modified to test the hypothesis by including copper pieces and copper sulphate to react with (and therefore reveal) the gas as copper sulphide. Evidence is presented in support of H2S production, which to our knowledge has not been shown before and introduces a potentially important avenue of investigation into self-heating mechanisms.INTRODUCTIONSelf-heating of sulphide minerals poses potential environmental and safety hazards in mining of ores, and storage and transport of concentrates. While some conditions are known to be critical, the reactions remain poorly understood making self-heating difficult to predict and control.A major advance in measurement was introduced by Rosenblum and co-workers [Rosenblum et al., 2001; Rosenblum and Spira 1995]. A self-heating assessment method was developed and applied to various sulphide-bearing materials The method is based upon automated calorimetric cells with data acquisition, now available to McGill researchers and which have been used for the study reported here."

Jan 1, 2006

By A T. Yuniar, C A. Brannon, N D. Pascoe, H H. Firdausi

This paper describes the key components of the Grasberg Block Cave (GBC) mine design and the development and construction status of the mine. Drawpoint production from GBC will be initiated in 2018 following the closure of the Grasberg open pit. Full production of 160 000 t/d is planned for 2024, which will make it a 20-year time period between initial access development in 2004 and full production.Diluted ore reserves are about 1 Bt at a grade of 1.0 per cent Cu and 0.78 g/t Au. The mine plans some 2400 drawpoints on a 20 m × 30 m drawbell spacing in a 700 000 m2 footprint using the El Teniente layout. The drawpoint opening sequence includes five production blocks, the first two of which are scheduled to be undercut simultaneously in 2018. Ore is transported using diesel-powered load-haul-dumps to a series of orepasses and then delivered via loading chutes to a rail haulage system, which delivers the ore to a three gyratory crusher complex. Crushed ore is transported to the mill stockpiles via dual inclined conveyors.Development and construction of the substantial fixed facilities are now well underway. Primary access for personnel and materials is via the 6 km Ali Boediardjo (AB) adits. A service shaft will hoist personnel and materials from the AB adits level to the various operating levels. Shaft commissioning is scheduled for late 2015. The rail haulage system installation and construction is in progress and is due to be commissioned in 2017, which is timed to coincide with the commissioning of the ore handling system. Ventilation is provided through a series of large intake and exhaust drifts, and two of the four main fans have been commissioned. A 1600 L/s pumping system will manage drainage from the mine.Other key facilities include separate shops for rail and rubber-tired equipment, warehousing, a powder magazine, a main control centre and an underground concrete batch plant.CITATION:Brannon, C A, Firdausi, H H, Pascoe, N D and Yuniar, A T, 2016. Development and construction update of the Grasberg block cave mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 625–634 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By N. Duru, C. Nesbitt

During the cyanide leaching process, gold and silver ores that come from the transition zones, which typically contains low levels of sulfide, may produce one or more of the following reduced sulfur species: sulfide ( HS−), polysulfides ( Sn 2−), thiocyanate ( SCN−), thiosulfate ( S2O3 2−), trithionate ( S3O6 2−), tetrathionate ( S4O6 2−), pentathionate ( S5O6 2−), hexathionate ( S6O6 2−). The actual speciation of the reduced sulfur species in the circuits will primarily depend on the redox potential, pH, cyanide levels, and existing sulfur species in recycled process water, as well as the presence of other reactive metal species. The development of an accurate analytical method for sulfur species in cyanide leaching units of gold ores where sulfur speciation occurs has an important role in explaining the metal recovery deviations. This study presents the speciation of sulfur species and the development of ion chromatography method to analyze reduced sulfur species thiocyanate ( SCN−), thiosulfate ( S2O3 2−), trithionate ( S3O6 2−), tetrathionate ( S4O6 2−) in cyanide leaching circuits for gold ores. The method developed has resulted in precise quantification of target sulfur species in leach solutions. Method development and validation results were illustrated on analytical graphs containing each species’ peak number, retention time (min), type, width (min), area (mAU*s), height (mAU), and area distribution (%) of the peak.

Mar 2, 2024

By William O. Vanderburg

This paper describing the mining practices at the Argonaut mine, Amador County, California, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The mining practices described are those used in exploiting the low-grade gold ores in the heavy and swelling ground that occurs on the Mother Lode belt. The author acknowledges the assistance of E. A. Stent, vice-president, James L. Fontenrose, cost clerk, Joseph Mohorovich, mine foreman, of the Argonaut mine, and of E. D. Gardner, supervising engineer, United States Bureau of Mines, Southwest Experiment Station, Tucson, Ariz.

Jan 1, 1930

By Edward Thomas

Yucca Mountain Overview The U.S. Department of Energy?s Yucca Mountain Project is a geologic repository project designed to receive, handle, package, transport, and emplace spent nuclear fuel and high level radioactive waste. The planned repository would be located in Yucca Mountain on the western edge of the Nevada Test Site, about 90 miles northwest of Las Vegas, Nevada, and would include both surface and subsurface areas. Yucca Mountain rock formations consist of successive layers of volcanic rocks (called tuffs) approximately 14 to 11.5 million years old, formed by eruptions of volcanic calderas to the north. With the volcanic rock the potential for methane emission is not an issue and the subsurface repository is a non-gassy (methane) classification. This paper will provide a summary of the development ventilation system design that provides fresh air for subsurface construction activities, and the emplacement ventilation system design that removes heat generated by the waste packages. The subsurface layout, illustrated in Figure 1, contains 108 emplacement drifts, one Performance Confirmation(PC) observation drift, nine intake/exhaust shafts, and three access ramps. The existing Yucca Mountain facilities, shown in bold lines in Figure 1, include a 7.8 km long, 7.62 m (25 ft) diameter U shaped tunnel that is formed by the North and South Ramps at both ends of the Exploratory Studies Facility (ESF) drift and a 1.5 km long, 5.0 m (16.4 ft) diameter Enhanced Characterization of the Repository Block drift (ECRB) that were constructed from 1994 through 1998. These drifts were used for site characterization activities and have been incorporated into the subsurface repository configuration. The unexcavated perimeter access main and exhaust main drifts are typically 7.62 m (25 ft) diameter TBM excavations and the emplacement drifts are 5.5 m (18 ft) diameter TBM excavations. The turnouts leading into the emplacement drifts are to be excavated by either mechanical, or drill and blast methods and serve as the launch chambers for the emplacement drift TBM excavations.

By C. H. Hopper

THE gold orebodies of the Matachewan Consolidated mine are of particular interest geologically because of their odd shapes, their apparent lack of connection one with another, and the fact that they occur in a number of different formations. All of the orebodies exhibit a similar fracture pattern and the areas of fracturing appear related to the local folding. However, the lack of either horizontal or vertical continuity suggests additional controls not yet discovered. The question of origin, so ably discussed by H. C. Cooke in 1919, will be reviewed in the light of the additional evidence uncovered since his examination of surface trenches twenty-four years ago. The Matachewan Consolidated mine, with its neighbour, the Young-Davidson mine, is in Powell township, 25 miles by road northwest from Elk Lake, 30 miles west of Kirkland Lake, and 45 miles southeast of Porcupine. It may be considered as being on the westerly extension of the Kirk-land Lake sedimentary belt, where the rock column is markedly similar. There is no similarity in structure, however, for great ore-bearing shears and faults simply do not occur at Matachewan. Rather may it be said that the region, under stress, failed in isolated brecciated patches, some of which make up today's orebodies. The mine currently treats 1,000 tons a day of porphyry ore averaging 0.10 oz. gold per ton. It started operations in 1934 on greenstone ore, and the mill then treated 150 tons a day of ore averaging 0.23 oz. gold per ton. Total production to the end of 1941 has been 929,484 .tons averaging 0.160 oz. gold per ton.

Jan 1, 1942

By Rob Farnfield

In the UK all new developments, including mines, quarries, tunnels, etc., are subject to a system of planning control. If the use of explosives is anticipated then such developments will attract a number of so-called ‘planning conditions’ relating to the blasting operation. This paper will outline a ‘typical’ set of conditions and how operators ‘plan to comply’. British Standards relating to both human and structural response are also reviewed and contrasted to the typical planning conditions previously outlined.

Jan 1, 2005

By Jim Peterson

Raising equipment that is commonly used include handheld drills such as Jacklegs or Stopers, Alimak raise climber also using handheld drills, drop raises using long-hole drills whether top hammer or ITH drill systems, Raise Bore machines and gang hammers or cluster drills such as the V-30 MRI attachment tool. Sometimes as a community we forget successful techniques used in the past and need to rediscover them.

Jan 1, 2014