Search Documents

By Roberto Maldonado

El presente texto señala el proyecto de profundización en la mina Animón considerando sus características como: geología e hidrogeología, parámetros geomecánicos, niveles de producción, costos de capital y operación, eficiencia del sistema, flexibilidad para cambios en las operaciones, reservas de mineral y consistencia con el sistema de explotación. De forma que a través del conocimiento de estas y de las herramientas gráficas tridimensionales, se pueda analizar las diferentes alternativas, incluyendo condiciones que debe cumplir el proyecto de profundización, el cual abarca también los servicios auxiliares y ventilación.

Sep 12, 2005

By R. Knapp, R. Firlotte

"Les Terrains Auriferes (LIA) Property, formerly the Malartic Goldfield (Goldfield) mine, ceased its remaining milling operations in the fall of 1994. During the early years of mining, the mill processed a non-sulfide ore with substantial carbonate mineralization.In 1977 after an extended shutdown period, ore from a nearby property, Bousquet, was processed at the mill. That ore contained larger quantities of sulfides, and unlike the old tailings, had acid generating potential.Upon closure of the L TA mill, the closure options considered for the L TA site were to cover with:1. a thin cover of 0.5 metres of borrow material (sand and gravel) to achieve basic erosion protection/stabilization; collect acidic seepage and treat with lime.2. a 2 metres of non-acid producing tailings; final surface to be vegetated.3. an engineered oxygen barrier consisting of a multi-layer cover; final surface to be vegetated.The paper presents the technological and economical methodologies that were used to select the closure alternative, describe the associated construction challenges that were faced with the implementation of the multi-layer cover concept and presents preliminary results on the cover's performance.In addition to being the first full scale demonstration of this type of multi-layer engineered oxygen barrier cover technology, this project had the advantage of using non acid producing mine tailings as part of the reclamation solution."

Jan 1, 1997

By Larissa Koroznikova, Steve Durkin, Patrick Bouwmeester, Michael Tuck

In currently used mining methods, blasting techniques often causes dilution of valuable ore and results in costly processing requirements. In the context of narrow vein mining of thin and highly concentrated orebodies there is a need of a mining method that can reduce dilution in order to remain economically viable. This research project explored the viability of a new mining technology, thermal fragmentation, in narrow vein mining. Thermal fragmentation technology uses a flame jet to produce extreme heat that spalls the surrounding rock to a strategically located drill hole, as an alternative to traditional blasting. This paper creates a net present value (NPV) model of a mining method using thermal fragmentation, as well as for an existing method used for narrow vein mining; comparisons and evaluations were made regarding the feasibility of the new technology. It was found that while overall costs for thermal fragmentation were relatively high, reductions in wages, haulage and processing costs, as well as increased productivity and ore recovery, meant that the new method would improve the financial performance of any operation. These results identify that there is an opportunity to introduce the thermal fragmentation technology to narrow vein mines within Australia, in order to lower costs and increase profit.

By Ajoy K. Singh, B Mohanty, P K. Singh

A study was conducted to investigate the damage potential to underground multiseam openings caused due to vibration generated by open-pit coal mine blasting. The objective was to recommend optimal explosives weight per delay to be detonated in open-pit blasts to ensure the safety and stability of underground openings. Sixteen blasts with varying charge weights and initiation sequences were conducted at Samleshawari open-pit mine and eighty four blast vibration data were recorded in the Hingir Rampur underground colliery in India. Analysis of vibration data showed that roof of the underground openings vibrated with much higher amplitudes compared to those in pillars and floors. The amplifications of vibration in the roof at the junction were upto 4.3 times the pillar vibration. It was observed that coal chips detached from roof when the peak particle velocity reached 131 mm/s or higher. The vibration magnitude recorded was higher in upper-seam openings than in belowseam openings. Rapid attenuation of vibration was recorded in below-seam openings at similar locations. Appropriate particle velocity-charge weight-distance equations were established to calculate the safe explosive weight per delay to be detonated in open-pit mine for the safety of multi-seams workings of underground mine. The support for the galleries and junctions were further modified for the working seams to ensure greater safety.

Jan 1, 2011

Jan 1, 1925

By Francisco Anglade

Dado que la simulación digital es una herramienta auxilar para los ingenieros de procesos -en tanto evalúa la factibilidad de un flowsheet propuesto y predice el efecto de una modificación para un flowsheet existente, su importancia también se extiende también a la evaluación de alternativas para las estrategias de control en los circuitos de la planta. En ese sentido, el presente trabajo señala los beneficios económicos y técnicos obtenidos en la planta San Rafael mediante el empleo de simuladores en los circuitos de molienda, chancado y concentración gravimétrica, los cuales permiten corroborar los cambios efectuados u optimizar los circuitos señalados de forma simple y rápida.

Sep 9, 2007

Removal of Arsenic in Enargite from Copper Ores by Flotation and Leaching in NaHS Media

Sep 13, 2010

By S. Stone

Because of problems encountered with conventional timber supports, a system of concrete sausageshaped support pillars was tested. The pillars are 3 m long, 0,6 m wide, and between 70 and 80 cm high (the height of the stoping width). They consist of bags filled with a grout of cement (slagment and sand in the ratio of I :2, and are installed in a staggered pattern 6 m apart on dip and 2 m apart on strike. These support packs have proved successful, and, although they cost more than the timber supports formerly used (R4,63 per cent are supported as against R2,26 for the conventional timber pack), their use is felt to be justified when account is taken of the costs of lost production and low productivity due to the bad hangingwall conditions that occurred with the conventional system.

Jan 1, 1978

IN the underground department of a mine, we may fairly say that "good management is based upon three elementals: first, sound engineering; second, proper coordination and efficiency of every human unit; third, economy in the purchase and consumption: of supplies.This paper is practically an analysis of the second element; which stands out prominently as the most important in the winning of successful results. The human units are divided into officers and men. The officers intermesh. One man takes responsibility where another throws it down; incessantly new conditions are arising where they may be doubtful of their powers; and always, on account of the three shifts, varying methods of work are coming into conflict. This very often results in disorganization. What is most necessary to guard against this is an esprit de corps, which would influence officers to stifle personal feelings for the general welfare of the department, To secure co-operation and loyalty of the staff, the writer recommends for the mines of the field a system of profit-sharing. Distributed on a salary basis, together with liberal holidays (not less than three weeks in each year) on full pay...

Jan 1, 1912

By B Putland, I Lovatt, D Schwann, A Cervillin

The Mount Carlton project in Queensland's North East sits on a high-sulphidation epithermal style deposit rich in gold, copper and silver. Mt Carlton is an open pit mining operation with ore processed using a primary crusher, single stage SAG mill and flotation to produce a concentrate for sale. Orway Mineral Consultants (OMC) was involved in the original design of the comminution circuit and the project was commissioned in late 2012, with first concentrate shipped in March 2013. When Evolution sought to optimise the project in 2015, OMC was invited to assist by undertaking a circuit review to identify opportunities for the optimisation. During 2016, the Mt Carlton site team implemented the optimisation strategies developed in conjunction with OMC. These included reconfiguring the SAG mill discharge arrangement, reducing the average ball diameter and allowing the mill to operate at higher speed and under more autogenous conditions. Cyclone operation was changed to constant pressure and the vortex finder size was decreased. The combined strategies improved energy efficiency and allowed higher SAG mill power utilisation. The additional power has been used to increase throughput by 2.4 per cent while achieving a 27µm reduction in product size (P80) to gain downstream recovery improvements. The reduction in grind size has been achieved with only 6.8 per cent increase in specific energy consumption because of a 6.5 per cent increase in grinding efficiency. The circuit product size is also notably more consistent due to the improvements made to the cyclones, providing benefit to the downstream flotation circuit. A significant decrease in ball consumption was also gained, saving hundreds of thousands of dollars a year in operating cost.This paper will discuss the circuit design, start up and will detail the changes made during the optimisation and why these were successful.CITATION:Putland, B, Lovatt, I, Cervillin, A and Schwann, D, 2018. Mount Carlton comminution circuit design, start-up and optimisation, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 517–528 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

Papers presented at a U.S. Bureau of Mines (USBM) technology transfer seminar describe the causes of violent material failure in U.S. mines, measurement techniques for monitoring events that result in violent failure, and mitigation techniques for controlling failure. Specific factors contributing to violent failure are identified on the basis of geotechnical monitoring in 16 U.S. hard-rock and coal mines and on statistical analyses of 172 coal bump events. New monitoring and analysis techniques developed as tools for assessing violent failure; geotomographic methods that provide new capabilities for the study of material failure and stress changes over large areas; and seismic methods for determining source locations, calculating energy release, and determining source mechanisms are described. Fair correlations have been established among seismic parameters, elastic stresses, face support load, and violent events. USBM studies have identified the advantages using both yielding and stable pillars for coal bump control. A computer program has been developed as an aid for selecting room-and-pillar layouts. The practical aspects of implementing a destressing program is outlined for coal mines, while the importance of mine orientation and timely support installation in controlling buckling-type failure is identified for hard-rock mines.

Jan 1, 1995

By R. Burger, M. Masukawa

Cato Ridge Alloys (CRA) is a joint venture company between Assmang of South Africa, Mizushima Ferro Alloy Company (MZK) and Sumitomo Corporation from Japan. Negotiations for the formation of the company started in 1992 with the joint venture agreement signed on the 19th September 1996. MZK was to supply the technical know how for the production of Medium and Low Carbon FeMn while Assmang was to manage the day to day activities of the company. Sumitomo Corporation was to act as facilitator between Assmang and MZK and, together with Ore and Metal are responsible for the marketing of the refined products. The conceptual design of the plant started in December 1996 and the first charge of molten high carbon ferromanganese metal was charged on the 19th January 1998. Problems experienced during the initial startup period were addressed resulting in substantial operational improvements. A build-up in the stock of fine metal was addressed through the development of a process to remelt the fine metal, the development of a market for fine metal and the upgrading of the crushing and screening plant to reduce the generation of fine metal. The mass yield from High Carbon Ferromanganese to Refined Ferromanganese was increased through the implementation of statistical process control, changes to the blowing patterns and the development of a sampling device for taking samples during the process. Converter refractory consumption was reduced. This was achieved on the converter by improving the cooling of the converters with the installation of cooling fans and cooling fins. The heating schedule of the converters was changed for improved refractory life. Production schedules were modified to allow cooling of the refractory between low carbon erromanganese charges. Additional changes made to improve operations were: ? Changing from mehanite casting trays to metal fines beds. ? Installation of sonic horns in the baghouse to prevent the bridging of dust. ? Improved welding on the lance tips.

Jan 1, 2004

By Kritika Baxla, M. Mustafa Kahraman, Frank A. Drews, Yaxue Wang, Joel M. Haight, Kody Powell, Mohit Sobalkar, W. Pratt Rogers

In the opinion of these authors, technology alone can never give an organization an edge over competitors or provide an industry step change. However, history has shown that technology applied with correct logistics and strategy makes a significant difference. Never has the minerals industry faced such daunting challenges and been in such need of a step change. Application of autonomous systems has been steadily increasing in the minerals industry. Automation technology has changed the mining value chain from exploration to mineral processing and refining. The future state will only see additional in-roads of automation into more processes and the whole system design. To better understand the near-future potential of automation, it is useful to explore and review the current state of automation in minerals development. A review of the state of automation research is given. The review will consider three critical areas: automation technology, system’s engineering and management processes around automation, and the role of human factors engineering in automated and semi-automated systems. The review ends with a discussion on the social and political risks of automation in terms of shared value and sustainable development.

In February 2001, Kalgoorlie Consolidated Gold Mines (KCGM) commissioned its first full-scale ultra fine grinding (UFG) plant to supplement existing roaster concentrate treatment capacity. This process involves the fine grinding of refractory pyritic concentrate to 10µm, followed by direct cyanide leaching for the recovery of gold. By this means gold is economically extracted from the concentrate without the need to first oxidise the host pyrite. This paper details the history of the project from initial laboratory testwork comparing possible treatment options, to current performance of the 12 tph plant. This includes the cost comparison of the major treatment options, the laboratory and pilot scale UFG performance, the UFG mill selection, cyanide leaching of UFG product, commissioning and plant performance to date.

Jan 1, 2002

By D. Komljenovic, E. Lafontaine, J. Paraszczak

Availability of the production equipment used in underground mines has a substantial impact on production costs and, thus, on mine profitability. Appropriate collection of pertinent data and information, as well as use of adequate performance measures and their analyses, can help mine operators identify cost-effective opportunities to improve equipment availability. This paper presents study results aimed at reviewing and analyzing means and measures used to quantify equipment availability and its contributing factors (reliability, maintainability and maintenance support) in several Canadian underground mines. It overviews sources, as well as quality and quantity of relevant data and information, and examines performance measures and their definitions, as applied to surveyed mines. Problems concerning data acquisition and meaningfulness of the performance measures are discussed. The paper concludes with some suggestions and recommendations concerning several aspects of equipment availability assessment. Evidence suggests that the latter may become a more useful tool for mine operators in their efforts to reduce production cost.

Jan 1, 2008

By Philip Dubbeling

Conventional dynamic sheetpiling techniques are ill-suited to urban development because of the emission of excessive noise and ground vibrations. Drilled shafts and slurry walls alleviate some of these environmental concerns but add additional problems due to large bulky machines, reliance on dusty concrete plants and urban trucking grief. To solve these problems, pre-fabricated sheetpiles are hydraulically jacked-in by reaction principle using a compact and lightweight press-in machine, a so called the "Silent Piler". Through scientific analysis, definition and systemization of press-in machines and methods, new construction concepts such as the one-step approach, implant structures, functional design and life cycle design have been developed to comply with new basic construction principles.

Jan 1, 2006

By Ray Hutton, Darrell Liebno, Taro Nonaka

Background Population growth and increasingly stringent regulatory controls on water quality across North America have resulted in municipal governments investing heavily in infrastructure to control what are known as Combined Sewer Overflows (CSOs).These are events which occur when combined sewers exceed their conveyance capacity during periods of heavy rainfall or snowmelt. The city of Atlanta, Georgia is one such municipality; with a population of over450,000 within city limits and a sewer system servicing 1.2 million including adjacent jurisdictions, the City of Atlanta has a Combined Sewer System (CSS) encompassing approximately 15% of its total 3,540 km (2,200 miles) of sewers. Atlanta’s CSO discharges to local watercourses began to draw fire from environmental groups in the1980s. As a result, in the early 1990s, the City constructed a series of CSO control facilities which provided screening and chlorination at seven CSO discharge points across the CSS watershed. Unfortunately, these facilities were not capable of handling all of the overflows generated due to heavy storm events; frequently, untreated water was bypassed around the treatment facilities. The federal Environmental Protection Agency (EPA) deemed that water quality standards were being violated by these discharges, and a suit was brought against the City to force a higher standard of compliance. As a result, the City entered into a federal Consent Decree which would bring CSOs into compliance with federal standards by 2007. A critical component of this plan was the design and construction of the West Area CSO Tunnels and Pumping Station. In February 2003 the City’s Department of Watershed Management retained the services of Jordan Jones & Goulding/Hatch Mott MacDonald/Delon Hampton Associates (JDH Joint Venture) to design and provide construction management ser-vices for the project, which was designed to capture combined sewage from three of the City’s existing CSO facilities on the northern end of the CSS watershed. The design consisted of two connected tunnels which would convey the wastewater originating from the North Avenue, Clear Creek, and Tanyard Creek CSO facilities to a submersible wet well pumping station located at the R.M. Clayton Water Reclamation Center (WRC). Since the majority of the effluent stream consisted of storm water, the City elected to design and construct a separate treatment plant. This plant was designed under a separate contract, and is currently under construction.

Jan 1, 2007

By A. Navarra, F. Mucciardi, H. Marambio, R. Parra, F. Oyarzún

"Discrete event simulation (DES) is an appropriate framework for the plant-wide analysis of copper smelters. These smelters apply a common set of chemical reactions: copper-iron sulfides are blasted with oxygen-enriched air, sending the iron into a slag phase and the sulfur into the offgas. Moreover, conventional copper smelters exhibit similar operational dynamics: a smelting furnace operates continually, feeding into an alternating set of converters that produce batches of blister copper. The thermochemical and operational commonalities of copper smelters are integrated within the DES framework. This serves as a common basis to begin evaluating the system dynamics of individual smelters. For complex problems, the simulation framework should be developed in phases, incorporating feedback from different personnel who have complementary perspectives. Sample computations are provided in this paper based on the Hernán Videla Lira smelter, whose production is constrained by meteorological conditions. IntroductionWorld copper production is approximately 18.5 million t/y (Brininstool, 2015), worth $80 billion a year. Out of this total, 75 percent comes from the pyrometallurgical processing of sulfide minerals (Fig. 1), which occurs in copper smelters. The remaining 25 percent is from the hydrometallurgical treatment of oxides and complex ores (Rotuska and Chmielewski, 2008), which uses solvent extraction and electrowinning.The current paper describes the pyrometallurgical processing, recognizing that the underlying thermodynamics and kinetics are well known (Degterov and Pelton, 1999), with the notable exception of minor element transport, such as arsenic (As), antimony (Sb), bismuth (Bi), silver (Ag), gold (Au). The latter is an ongoing area of research, as smelters are faced with increasingly complex ores (Devia, Wilkomirsky and Parra, 2012; Swinbourne and Kho, 2012). This paper focuses on the system dynamics of copper smelter operations, which has received considerably less attention than the chemical thermodynamics and kinetics.Smelter engineers and managers may contribute to the sustainability of their plant by improving their understanding of operational system dynamics. Indeed, we have prompted smelter improvement projects (Navarra, 2016; Navarra et al., 2016; Navarra and Mendoza, 2013) simply by adapting methodologies that are commonly used in other sectors. These previous works incorporate principles from computer-integrated manufacturing (Groover, 2000) and theory of constraints (Dettmer, 2007), featuring the use of discrete event simulation (DES)."

Jan 1, 2017

By Christopher Mark

Knowledge of in situ stresses is fundamental to many studies in earth sciences, and coal mine ground control is no exception. During the past 20 years, it has become clear that horizontal stress is a critical factor affecting roof stability in underground coal mines. The theory of plate tectonics and the World Stress Map (WSM) project has been extremely helpful in explaining the sources and the orientations of the horizontal stresses observed underground. Recently, WSM geophysicists studying deep-seated stresses have developed a model of how stress magnitudes vary with depth in the crust. They have devoted relatively little attention to near-surface stresses, however. This paper explores the relationships between deep-seated and shallow in situ stresses in several of the world?s coalfields, using a data base of more than 350 stress measurements from underground coal mines. The analysis indicates that distinct regional trends exist, corresponding roughly to the regional stress fields identified by the WSM. The paper presents equations for estimating stress magnitudes that were developed by treating depth and elastic modulus as independent variables in regression analysis. The magnitude of the horizontal stress increases with depth, at rates that range from 0.8 to 2.0 times the vertical stress, just as the WSM ?critically stressed crust? model predicts. Overall, it seems that the stress regimes encountered in underground coal mines are closely linked to those that exist deep in the earth?s crust.

Jan 1, 2008

By D. J. Leidel

The offshore production of oil and gas resources has been active in the Gulf of Mexico since Kerr- McGee drilled the first commercial well out of the sight of land in 1947. Since then, approximately 60% of the offshore oil/gas production structures used globally have been erected in the GOM to support the production of energy resources’. The shallow, shelf and shelf edge waters of the Gulf of Mexico have reached or are rapidly approaching production maturity, requiring that the fixed structures used to support energy production be removed or otherwise disposed of by suitable means. The use of energetic materials has been determined to be a safe, efficient and cost effective technology to remove fixed offshore structures whose service life has been exceeded.

Jan 1, 2002