Search Documents

By D. R. Lentz, C. J. Beaumont-Smith, S. H. Mcclenaghan

"Abstract - The Louvicourt Au-Ag-Cu-Zn-Pb sulfide deposit is hosted by a Middle Ordovician calc-alkaline sequence of aphyric rhyolite flows and associated fragmental rocks at the top of the Flat Landing Brook Formation. The Zr/TiO2 (average = 0.110) and Y/TiO2 (average = 0.021) ratios in the footwall felsic volcanic rocks are consistent with known values for the Reids Brook member. The deposit consists of two concordant lenses of semi-massive to massive sulfides, approximately 150 m long and up to 9 m thick, which represent a fold repetition of a single exhalative horizon. The deposit contains a geologic resource of 136 000 tonnes grading 1.2% Pb, 1.0% Zn, 0.4% Cu, 90.9 g/t Ag, and 0.96 g/t Au; the deposit locally contains elevated Au (2.9 ppm) and Ag (320 ppm) contents. A laterally continuous iron formation that contains barite caps the deposit, and is gradational vertically and laterally into laminated siltstone. The exhalite confirms the stratiform nature of this deposit, but a large percentage of sulfides occur as late replacements of altered felsic fragmental rocks in the footwall. Abundant examples of colloform pyrite and perlitic and spherulitic textures in volcanic clasts are well preserved. The base- and precious-metal content of the Louvicourt deposit is atypical of the Bathurst Mining Camp (BMC). Reported assay data (n = 27) indicate an average Pb/Zn ratio of 2.6, the highest in the BMC (average = 0.39). Lead exhibits a strong Spearman Rank correlation (r' = 0.92) with base metals throughout the sequence, indicating a preponderance of galena in both the stockwork and stratiform zones. The Ag and Au contents in this deposit are among the highest in the BMC and exhibit a Au-Ag- Cu-Pb association. Barite-rich exhalative pyrite exhibits a moderate Au correlation with Ag (r' = 0.77; n = 10) and Cu (r' = 0.76) and occurs in portions of the exhalative sulfides that are enriched in Pb. Chemical exhalative rocks are conformably overlain by trachy-andesitic volcaniclastic (possibly pyroclastic) rocks that are assigned to the Little River Formation. These are enriched in Nb (average = 38.4 ppm) and P2O5 (average = 0.17 wt.%), and have much lower Zr/TiO2 (average = 0.056) and Y/TiO2 (average = 0.0062) relative to rocks higher in the hanging wall. The intermediate volcanic rocks are conformably overlain by massive to pillowed basalt flows and related hyaloclastite that have Nb/Y = 0.60 and high TiO2 contents (average = 2.8 wt.%). This chemistry is consistent with rocks of the Brunswick Mines member (Little River Formation), except that these rocks are considerably enriched in P2O5 (average = 0.82 wt.%). This syngenetic exhalative deposit is unique for the BMC with a high Pb/Zn and elevated Au and Ag contents, as well as an epithermal signature (Sb-Ag-Au-Tl-Hg), analogous to high sulfidation volcanogenic massive sulfide deposits. Its intimate relationship with an emergent felsic dome (Flat Landing Brook Formation), chlorite-silicate-oxide-sulfide exhalite (locally hematitic), and the abundance of barite are classical features of many of the Kuroko deposits."

Jan 1, 2006

By A. Ghahremaninezhad, E. Jorjani, A. Riahi, Islamic Azad University, B. Nazari, H. Hani, Z. Manafi

The presence of a high iron concentration, 9.1 g/L, in the raffinate of the Sarcheshmeh copper heap bioleach process led to the formation of various types of jarosite, (K,Na,NH4,H3O)Fe3(SO4)2(OH)6, on the heap mineral surfaces. This study probes iron removal from the raffinate using a bio-oxidation process based on A. ferrooxidans bacteria in the presence and absence of jarosite seed. The jarosite seed was biologically synthesized using A. ferrooxidans bacteria. The effect of solution pH (1.5 to 2.5) and jarosite seed dosage (0 to 15 wt.%) on iron removal was examined. It was demonstrated that the concentration of iron ions present in the raffinate decreased from 9.1 g/L to 2.5 g/L with the addition of 10 wt.% jarosite seed at pH 2 and 130 rpm mixing rate at 32°C. Three different types of raffinate including (1) native raffinate containing 9.1, 3.4, 5.7 g/L of total, ferric and ferrous iron, respectively, (2) bio-oxidized raffinate in the absence of the jarosite seed containing 8.5 g/L total iron (mainly ferric with negligible ferrous), (3) bio-oxidized raffinate in the presence of jarosite seed containing 2.55 g/L total iron (mainly ferric with negligible ferrous) were used in mesophilic, moderate thermophilic and thermophilic bioleaching processes. The results of the flask tests showed that the highest copper bioleaching recoveries of 9.4, 49.4 and 90.8 % were achieved using raffinate (3) with mesophilic, moderate thermophilic and thermophilic bioleaching processes, respectively.

Jan 1, 2016

By Victor L. Stevens

The Oso tunnel is one of three tunnels located on the San Juan-Chama Project in south-central Colorado. The purpose of the tunnel is to carry water from the upper San Juan watershed through the Continental Divide into the Rio Grande watershed. The Oso tunnel contract was awarded by the U.S. Bureau of Reclamation to a joint venture of Boyles Brothers Drilling Co., Gibbons & Reed Co., and Cimco in February 1966. The Oso tunnel is 26,660 ft long and has a rock section of 10 ft, 2 in. with a lined diameter of 8 ft circular. The main portion of the rock formation was in the Lewis shale. This formation is quite consistent in hardness and texture with exception of localized limestone concretions and sandy siltstone inclusions. The job was bid on the basis of using a James S. Robbins mole of the P221 series. The decision for using a mole was predicated on the geology and the experience of the same joint venture on the adjoining Azotea tunnel where a mole was successfully used. The Robbins P221 series mole is capable of cutting from 9 ft, 11 in. to a 10 ft, 7 in. diam without any major change. It is 40 ft long and weighs 60 tons. The cutting head has 22 disk-type cutters and one center pilot (standard 9 7/8 -in.) tricone bit. The head is powered by four 75 hp electric motors. Gripper pads at about the midway point on each side of the machine are pushed into the tunnel ribs and thrust-cylinders in front of each gripper apply pressure to the face as the head rotates. The regripping cycle is 3 ft and then the grippers are retracted and advanced. Each cutter on the perimeter of the head is followed by a bucket which scoops up the cut material, almost in the same manner as a water wheel, and dumps it into a conveyor situated along the top of the mole. The muck from the mole conveyor is dumped into a gantry-type conveyor. The gantry conveyor is 350 ft long and is pulled

Jan 1, 1970

By Pierre de P. Ricketts

Having had occasion while in Europe during the past summer to visit some of the foreign mints and assay offices connected with the same, I thought a brief description of the general process of coining employed, and such items connected with assaying as were new, might prove interesting to the Institute. The principal foreign mints are: the Royal Mint, London; and the mints in Paris, Brussels, Utrecht, Berlin, Vienna, Copenhagen, St. Petersburg, Stockholm, Madrid, Milan, Rome, and Constantinople. My time only permitted my visiting a few of the principal and largest given in the list, and for a description of the remainder I am indebted to the kindness of Mr. James M. Napier, who in company with the deputy master, and chemist of the Royal Mint, made a complete inspection of all the European Mints in 1870.

By Pierre de P. E. M. Ricketts

HAVING had occasion while in Europe during the past summer to visit some of the foreign mints and assay offices connected with the same, I thought a brief description of the general process of coining employed, and such items connected with assaying as were new, might prove interesting to the Institute. The principal foreign mints are: the Royal Mint, London; and the mints in Paris, Brussels, Utrecht, Berlin, Vienna, Copenhagen, St. Petersburg, Stockholm, Madrid, Milan, Rome, and Constantinople. My time only permitted my visiting a few of the principal and largest given in the list, and for a description of the remainder I am indebted to the kindness of Mr. James M. Napier, who in company with the deputy master, and chemist of the Royal Mint, made a complete inspection of all the European Mints in 1870.

Jan 1, 1876

By FREDERICK MCAKCCOY

THE production of tin from Mexico has never reached the point of being considered a national industry, but the distribution of tin ores is so widespread that there are possibilities that one day it may become of importance. Of the twenty-seven states of the Republic, tin claims have been taken up in sixteen. In all there had been taken up to the end of 1926, two hundred and twenty-five claims, of a total area of about 7400 acres. The first historical mention of tin in the Americas is found in a letter of Cortez to the Emperor, Charles the Fifth, of Spain, which is as follows: Speaking of his manufacture of some small cannon, he says: "For these reasons I took considerable pains to get copper from some provinces of this country, and bought it at a high price in order to get it quicker.

Jan 1, 1929

By Atta Ur Rehman, Kwame Awuah-Offei

"Information diffusion potential of a social media user affects how quickly information about a mineral project can diffuse through that user. If management can use social media and network analysis in community engagement programs to understand how fast and how far information will diffuse to communities and followers of particular social media users, it can selectively focus on the most influential users. This article proposes a method to examine the information diffusion potential of social media accounts. The work uses Gephi, an open source software, to extract and analyze data from different Twitter handles to predict their information diffusion potential. The work uses case studies of real Twitter users (e.g. mining news organizations and bloggers) associated with mining to illustrate the approach. The case study results show that there are significant disparities in information diffusion potential that will demand selective attention. This research will help mines develop effective social media engagement strategies.The mineral industry provides raw material for industrial activity to support society (Martens and Rattmann, 2001). Mines have changed from conventional mining practices to sustainable ones because of the negative impacts of mining in the past and increased public awareness (Wang et al., 2016). The concept of sustainable mining is getting mature, as stakeholders (e.g., governments, investors and host communities) are getting more involved in mining projects (World Economic Forum, 2014). The failure of mining companies to address the demands of these stakeholders might result in the failure to acquire a social license to operate (SLO) (Thomson and Boutilier, 2011). The SLO, if granted, is mutually beneficial to all stakeholders. Mines prefer being granted SLO and keeping it to avoid any kind of social unrest due to their operation (Prno, 2013; Moffat and Zhang, 2014). Mining communities can grant different levels of SLO ranging from withholding SLO to psychologically identifying with the project (Joyce and Thomson, 2000; Thomson and Boutilier, 2011).Most of the previous work to understand community perceptions and SLO in mining is generally qualitative (ICMM, 2012a; Thomson and Boutilier, 2011; Prno, 2013; Moffat and Zhang, 2014; IFC, 2014). In particular, there is limited work on how community perceptions change over time due to information diffusion (Boateng and Awuah-Offei, 2017). However, SLO changes with respect to time (Yates and Horvath, 2013), which can result in risks that are not easy to predict. Mine managers and engineers have a desire to understand these changes so as to mitigate these risks (Que and Awuah-Offei, 2014; Que et al., 2015)."

Jan 4, 2018

The Iron Ore Company of Canada (IOC) is the largest manufacturer of iron ore pellets in Canada and its customer base covers North American, European and Asian steel producers. The company operates a mine, concentrator and a pelletizing plant in Labrador City, Newfoundland and Labrador, as well as port facilities located in Sept-Iles, Quebec. It also operates a 418-km (260-mile) railroad that links the mine to the port. IOC has approximately 1,900 employees. Its shareholders are Mitsubishi Corp. (26.18 percent), Labrador Iron Ore Royalty Income Fund (15.1 percent) and the international mining group Rio Tinto, which is its major shareholder (58.72 percent) and operator, with activities in more than 40 countries throughout the world. The IOC was incorporated in 1949 and by 1954 it had completed the Quebec North Shore and Labrador (QNS&L) rail line. IOC began mining in Schefferville, Quebec by 1954 and closed those operations down in 1982. In 1962, IOC commissioned the present day Carol Project consisting of mining, concentration and pelletizing facilities in Labrador City, Newfoundland. In 2004, IOC shipped its one-billionth tonne of ore on the QNS&L Railway. In 2005, IOC celebrated 50 years of mining history. The company expressed an interest in reducing the amount of oversize material (>1 m x 1 m x 1 m or 3.2 ft x 3.2 ft x 3.2 ft) being produced and its subsequent downstream effects, including in-pit sorting and reduction, damage to mobile equipment and significant delays in the loading pockets and the primary crushers. To achieve this goal, an oversize reduction project was undertaken by the mine that, to date, has significantly improved upon baseline measures. One key approach used to reduce the amount of oversize was the implementation of thicker emulsion. The introduction of a thicker emulsion provided more resistance to the forces created by dynamic water and reduced the infiltration of the emulsion into the cracks and fissures of the rockmass, resulting in reduced amounts of oversize and more consistent fragmentation throughout the muckpiles. Additionally, a significant reduction in nitrates leached into the mine water discharge has been realized. To determine the effectiveness of the oversize reduction project, IOC used a first-of-kind technology to assess fragmentation presented to the shovel at the digging face. A digital vision system (DVS) was installed on one of the shovels to capture images that were stamped with GPS locations. A large population of digital images were analyzed to produce a robust fragmentation distribution baseline that was used as one of the mine key performance indicators (KPI). Changes to blasting practice were subsequently measured against the baseline KPI to assess effectiveness.

Jan 1, 2011

By Kasimcan Koruk, Julian M. Ortiz

A geological model accounting for uncertainties possesses important advantages for resource estimation. Machine learning algorithms (MLAs) employed on multivariate geochemical datasets open up ways to new methodologies for such geological models with ease in comparison to traditional geostatistical methods. This article proposes a two-step MLA with an ensemble implementation to define geological domains and their uncertainties based on geochemical data. The proposed workflow is applied hierarchically on a dataset from a porphyry copper deposit to perform binary classification that can be attributed to alteration domains.

Mar 1, 2024

By W. G. Pariseau

"The Crandall Canyon Mine (CCM) is located in the Wasatch coal field in central Utah. Extensive longwall mining at CCM preceded a decision to recover coal left in barrier pillars on each side of a set of main entries extending far into the mine. During mining in March 2007, a major bump occurred that led to cessation of mining in the barrier pillar on the north side of the mains and to the start of mining in the south barrier pillar. Subsequent loss of ground control in August 2007, through coal pillar bursts had tragic consequences with loss of six miners and shortly afterward three rescue team members. A U.S. Mine Safety and Health Administration (MSHA)report describes the events in detail (MSHA, 2008).An important lesson to be learned from CCM is the need to select a computer program suitable for pillar design. Computer programs are engineering tools and selecting the right tool for the job is essential. In this regard, minimum program requirements include capability for computing stress distribution within a pillar and adjacent roof and floor strata. The reason is simple: strength of rock is stress dependent; both vary from point to point in pillars and adjacent strata. Preferably, one should follow the evolution of stress as the mining plan is executed from start to finish to assure safety or to warn of a potentially hazardous situation developing as mining progresses.The approach to the problem posed by barrier pillar mining at CCM is conventional in the sense of applying well known finite element modeling techniques to analysis of a proposed mining plan. The engineering purpose is to evaluate the mining plan with respect to ground control questions including roof, floor and pillar safety. Results of previous two-dimensional finite element analysis indicated pillar safety was by no means assured (MSHA, 2008; Pariseau, 2008; Pariseau, 2011). Geometry of barrier pillar mining is limited in two dimensions for example, crosscuts are not seen in vertical cross sections. While three-dimensional analyses are preferred, even moderately sized regions often lead to very large problem sizes that exceed computer capabilities. However, a recent development in finite element modeling of tabular deposits allows for whole mine analysis in three dimensions. This technique involves a dual node - dual mesh concept. Both have been used separately in much earlier work, but are only now used in combination. It is possible to have an estimation of subsidence at a kilometer scale and details of stress, strain and displacement about barrier pillars, main entries and pillars, and so on at a meter scale (Pariseau, 2014). No compromise involving empirical formulas or similar guess work is required. Indeed, all calculations are based on first principles: physical laws, kinematics, and material laws. Effects of joints and in situ variability or uncertainty in strata properties, elastic moduli and strengths, may be included for greater realism. An important objective of the present study is to assess the role of three-dimensional pillar geometry in arriving at conclusions regarding barrier pillar mining versus two-dimensional results."

Jan 1, 2014

By Enrique Mansilla

El presente texto señala la historia y desarrollo económico de la plata como metal peruano en el mundo. El Perú antiguo y tradicional fue productor de este metal desde el siglo XIV. Sin embargo, la mayor parte de esa riqueza fue llevada a la metrópoli española y en consecuencia, se optó por la producción de oro. El Perú produce solo el 0.26 °/o de la producción anual de oro con un valor de U$ cinco millones. Si se lograse reponer el antiguo sistema mundial de monetización de la plata, este sistema recuperaría el valor que tuvo hace 100 años a.C o hasta fines de la Colonia española, o sea la relación de 15 a 1 con respecto al valor del oro.

Jul 1, 1973

By N. Duda, W. Koperska, S. Anufriiev, P. Stefaniak

In mineral processing plants ore extracted from mines is processed to obtain a concentrate with the highest possible concentration of this valuable product. It is a complicated multi-stage process. Usually, the first step is sieving the ore, which is typically done using vibrating mining screens. There is often only a limited number of these machines in the technological chain, which is why their continuous operation, and proper maintenance is crucial for the whole process. Predictive maintenance is the best strategy in this case because it allows for minimising the number and duration of unexpected stoppages. It consists of the prediction of future failures based on available real-time data, and predictive models built upon this data using, for example, machine learning techniques. In this paper we concentrate on feature generation for future predictive maintenance model development for a vibrating screen, based on an example of a KGHM ore processing facility in Polkowice-Sieroszowice. We focus on two types of measurements: bearings temperature and vibrational data. Based on the raw data, the process of more advanced feature engineering is described. By transforming the temperature data we calculate characteristics of bearing cooling and heating dynamics, while based on vibrational data, the aggregated characteristics of the vibrations are derived. Such features are calculated on a long-term basis, and then they are compared to the data related to vibrating screen maintenance to estimate their significance for the prediction of particular failures of the machine.

Sep 1, 2021

1. Domestic Production and Use: In 1979, 12 companies operated 32 primary aluminum reduction plants, with 3 firms accounting for 64% of production. Washington, Oregon and Montana accounted for 32% of the total production; Gulf Coast States 20%; other Northern States 32%; and other Southern States 16%. Based on published producer prices output of primary metal in 1979 was valued at over $6 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1979, building accounted for about 24%; packaging 23%; transportation 22%; electrical 11%; consumer durables 8%; and other uses, 12%.

Jan 1, 1980

By D. Chetty

Process mineralogy forms an integral part of geometallurgy, with ore body characterisation being but one piece of the puzzle in optimising value derived from ore. This value is not only financial, but importantly speaks to sustainability from environmental and social standpoints. The reactive approach of traditional process mineralogy is increasingly being replaced by predictive methods in the geometallurgical sphere, for which mineralogical information must be timeously acquired on judiciously selected sample sets to understand ore variability and its impact on orebody processing. Such processes are not only metallurgical, but must incorporate mining and waste management protocols. Dwindling resources like water and energy also demand innovative approaches for lowering consumption and/or promoting recycling along the value chain. Addressing such challenges relies on appropriate characterisation of ore behaviour under different process regimes. Coupled with this, emerging characterisation tools are increasingly applied to understand the mineralogy of unconventionallypresented and difficult-to-process ores to meet societal and technology demands. Such tools are often accompanied by the generation of large, computationally intensive datasets, for which data management and storage are key requirements, particularly when deciphering temporal trends in ore and process variability. This paper will elaborate on these themes with examples that highlight the importance of process mineralogy throughout the minerals value chain. Keywords: Process mineralogy, ore characterisation, geometallurgy

Jan 1, 2020

By S. L. Huang

The location and shape of potential failure surfaces in soil slopes were directly determined based on the stresses induced in the soil mass and the strength of the soil itself. Stress calculations were carried out by the finite element method with the Drucker-Prager nonlinear material model. The Mohr-Coulomb failure criterion and Mohr's circle stress analysis were then applied to the calculated stresses to determine the characteristics of the failure surface.

Jan 1, 1989

THE Synthetic Liquid Fuels Act. (30 U.S.C., 321-325, and amendments) became law April 5, 1944, and a period of intensive research and development in this field was begun by the Bureau of Mines. As part of this program, bulletins were published on pressure hydrogenation.3 the Fischer-Tropsch synthesis,4 anal oil shale.5 The Bureau also has published a short bibliography on coal gasification,6 mostly of a theoretical nature. Because coal gasification is prerequisite to either the Fischer-Tropsch or coal-hydrogenation processes, publishing this sizable collection of technical information in this form will be valuable. The material will be presented in three parts, as follows: I. United States Patents. II. United Kingdom Patents. III. Other Foreign Patents. The domestic patents for this bulletin were collected between 1953 and 1955.

Jan 1, 1960

By Steve Kral

The dramatic rescue of nine Pennsylvania coal miners trapped nearly 90 m (300 ft) underground for77 hours probably would not have happened without the high technology equipment and improved mine rescue training techniques available today. By now, most everyone has heard the story of the accident that occurred at the Quecreek Mine near Somerset, PA. At about 9 pm on Wednesday, July 24, the miners were drilling coal in the room-and-pillar mine. Their drilling accidentally punched through to the adjacent, abandoned Saxman Mine. Old mine maps of the Saxman Mine led Black Wolf Coal, Quecreek’s owners, to believe they were between 60 to 90 m (200 to 300 m) away from the abandoned mine. Those maps proved to be inaccurate.

Jan 1, 2002

By Brian Zelenko, William H. Hansmire

"By the time the latest expansion of the Washington Metropolitan Area Transit Authority (WMATA) system, known locally as Metro and which opened in 1976, is completed in 2020, the system will serve 97 stations and operate on 188 km (117 miles) of track on six interconnecting lines. Metro provides a critical transportation link to a population of approximately six million people within a 3,900-km2 (1,500-sq-mile) Washington Metropolitan area and has allowed job growth to expand to all corners of the region. In the 1950s and 1960s, when the system was first conceived and construction began, most jobs were centered in downtown Washington, and most of the workforce commuted by bus or car. Today, transit-oriented development has increased residential, commercial and government facilities near most of the existing 91 stations increasing the importance of the Metro system as a critical transportation link for the region. According to recent American Public Transportation Association (APTA) data, Metro is the second busiest transit system in the United States (after New York City’s transit system).During the nearly 50 years of construction on the Washington Metro system, technology improvements and lessons learned from the global tunneling industry were implemented. Portions of this background and history have been adapted from other work by the authors Roach et al. (2017) and expanded for use herein. For soil tunnels, these improvements included the change from a “two-pass” tunnel lining with a typical initial lining of steel ribs with wood lagging or segmental precast lining erected within the tunnel shield followed by a final lining of cast-in-place concrete to a one-pass lining system of pre-cast concrete gasketed segmental lining. Soil tunnels were originally excavated using open-face tunnel shields, but changed over time. By the late 1980s, tunneling using closed, pressurizedface tunnel boring machines (TBMs) using a one-pass tunnel lining consisting of segmental precast concrete permitted tunneling in a wider range of soil conditions with much less risk of damaging overlying utilities or structures, greater safety for tunnel construction personnel and without the need to dewater the soils. However, due to concerns about conditioning clays with earth pressure balance (EPB) TBMs, open face machines were still favored by contractors for their better advance rates, lower cost and ability to deal with boulders that were occasionally encountered in the Coastal Plain Terrace Deposits."

Jan 6, 2018

[ENGLISH active earth pressure adapter additive adhesion admixture, addition adsorbed water aggregate air air entrainment air hose allowable bearing value allowable pile bearing load]

Jan 1, 1994

By J. N. Geyer

During the early stages of the mining industry of the United States an apparently inexhaustible supply of high-quality, easily accessible coal made the product cheap and the attendant mining methods wasteful of recoverable coal. Because coal from advance places could be mined with less effort and a large outwit obtained as the entries advanced, much of the coal left in pillars to support the roof was lost. Squeezes often developed in these mined-over areas, or, if pillars were of sufficient size to-prevent squeeze, the roof would be so weakened by long exposure that any pillar recovery was extremely hazardous. As the value of unmined coal increased, a high recovery of the available coal became necessary. Numerous plans were tried during the period that followed, some of the methods proving successful while others were complete failures or only partly successful. As a better knowledge was pained of the roof strata and its behavior, however, pillar mining became more successful and methods suited to special roof conditions were developed.

Jan 1, 1933