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By Y. Wang

In this study, homogeneous (unseeded) precipitation of nesquehonite (MgCO3.3H20) by the reaction of MgC12 with (NH4)2CO3 in supersaturated solutions at 30 °C was investigated. Factors which influence the precipitation of MgCO3.3H20, such as initial concentration, temperature, stirring speed, titration speed, equilibration time, have been studied. SEM images show that the initial concentration and titration speed have significant effect on nesquehonite's crystal morphology and particle size. In addition, stirring speed and equilibration time also have some influence on its properties. With the optimization of operating conditions, the crystals can grow up to a length of about 40µm and a width of 5µm, indicating good filtration properties. High purity nesquehonite obtained in this study was calcined to produce highly pure MgO at 800 °C as shown by XRD results. The novel process may be used to separate Mg and Li from high Mg/Li ratio brines in Qinghai, China.

Jan 1, 2007

By Raymond S. Suglo

Increasing depths of mining coupled with the mechanization of most underground mining operations have led to growing complexities in the mine environments with the production of large amounts of gaseous and particulate contaminants. Over 100,000 lives have been lost due methane gas and dust explosions in coal mine workings in both the US and Canada since 1900 when the methane concentrations exceeded stipulated levels in some workings. There is therefore the need to constantly assess and evaluate the performance of the existing mine ventilation systems to maintain safe and acceptable mine environmental conditions in workings to meet the requirements of federal, state or provincial laws. This paper uses the results of continuous monitoring of methane concentrations conducted in selected development headings in coal mines in North America to assess the effectiveness of existing auxiliary ventilation systems in the control of methane gas concentrations in the headings. The results show that the average quantities of fresh air required to dilute, disperse and remove methane concentrations within set levels of one minute varied from 5.43 m3/s in Heading #11 (Condition 2) to 27.97 m3/s in Heading #10 (Condition 1) and this represented about 12 to 26% of the quantities required to dilute methane concentrations to safe levels within one minute under Condition 1 and 32 to 139% under Condition 2. The average dilution times in the headings studied were less than 8 minutes. The forcing efficiencies of the auxiliary systems in the headings studied ranged from poor to excellent implying that the auxiliary ventilation systems were capable of controlling the methane concentrations below statutory levels but may not be able to cope with large and unusual methane concentrations in the headings. This study is important to prevent methane gas and coal dust explosions in coal mines and thus avoid any loss of lives and property.

May 1, 2001

By M. Abumiya, N. Onodera

"The synthesis of large scorodite particles in non-ferrous metallurgical industries usually requires a high-cost operation involving heating and high-pressure autoclaving. To overcome these obstacles, an atmospheric-pressure process for scorodite synthesis (DMSP®) was developed, in which ferrous ions were oxidized by oxygen gas in the presence of pentavalent arsenic ions. This process gives scorodite of good crystallinity with particle sizes as large as 15-20 µm. The solutions used for scorodite synthesis in the DMSP® are prepared from various residues containing arsenic from non-ferrous smelters. The solutions may be contaminated with Cu, Sb, and Bi, for example, and therefore the effects of such impurities on the formation of crystalline scorodite need to be investigated. In this study, the effects of Cu, Sb, and Bi contaminants on the formation behaviors of scorodite particles in the DMSP® were investigated systematically.INTRODUCTIONThe synthesis of crystalline scorodite (FeAsO4·2H2O) is a suitable method for arsenic (As) stabilization and storage of As-containing by-products such as flue gas dusts in non-ferrous smelters. It is expected that the formation of large, highly-crystalline scorodite particles would be an ideal method for avoiding the release of arsenic to the environment. Generally, autoclave methods under pressurized oxidation conditions at temperatures above 100°C have been used for the formation of arsenic minerals such as scorodite. However, the autoclave method requires sealed vessels that are resistant to high pressure, heat and acids. This process is also unfavorable on account of the high construction expenses, and high running costs as a result of vapor heat loss. Processes for synthesizing scorodite under atmospheric conditions at temperatures below 100°C which do not need an autoclave have therefore been extensively investigated (Demopoulos, Droppert, & VanWeert, 1994; Demopoulos, 1996; Demopoulos, Lagno, Wang, & Singhania, 2003; Droppert, Demopoulos, & Harris, 1996; Filippou & Demopoulos, 1997).Recently, Fujita et al. (Fujita, Taguchi, Abumiya, Matsumoto, Shibata, & Nakamura, 2008a, 2008b, 2009; Fujita, Taguchi, Kubo, Shibata, & Nakamura, 2009; Fujita, Taguchi, Shibata, & Nakamura, 2009) developed a new method for producing large scorodite crystalline particles with improved filtration and washability properties at normal atmospheric pressure and temperatures below 100°C. In the new method, oxygen gas (O2) is blown into solutions containing a high concentration of arsenic ions (As(V)) and ferrous ions (Fe(II)). The Fe(II) ions were subsequently oxidized to ferric ions (Fe(III)), resulting in the formation of large scorodite particles. High supersaturation of solutes such as Fe(III) will result in excessive nucleation, and the formation of poorly crystalline phases. The scorodite formation must therefore be conducted in a manner that avoids the critical supersaturation level being exceeded. It is supposed that the oxidation of Fe(II) to Fe(III) by O2 gas in the new method suppressed the supersaturation of Fe(III) during scorodite formation. The low Fe(III) supersaturation resulted in formations of highly crystalline scorodite particles of size of around 20 µm. In June 2008, based on the developed process described above, DOWA began experiments to verify the industrial capability of a plant with a capacity of 30 MT/month of As. It was successfully proven that it is possible to produce crystalline scorodite industrially on a commercial scale. This process was named and trademarked as DMSP® (Kubo, Abumiya, & Matsumoto, 2010)."

Jan 1, 2012

By Lorrie Fava

Two needs in the mining industry, to enable overall process improvements, are open systems and network connectivity in underground mines. The Pando project, a collaboration between Symboticware, Vale and Xstrata Nickel, and supported by CEMI, addresses these issues, and leverages the solution platform to deliver intelligent applications. An open system is one that uses publicly available standards for its key interfaces. Vendor-neutrality and ease of information flow are two main benefits that result from the use of open systems. By facilitating the interoperability of systems, open systems allow information to be available when and where it is needed for decision support. Network connectivity in underground mines is typically limited, with hotspots in strategically chosen areas that are relatively static. Mobile equipment moving through a mining work cycle experiences intermittent connectivity; in this situation, seamless remote equipment monitoring is impossible. The Pando project establishes an open technology platform, adhering to the IREDES and OPC UA standards. It enables the collection and integration of information generated by mobile equipment? seamlessly while there is a network connection, and as a store-and-forward gateway to manage intermittent connectivity. The platform capabilities are leveraged to support embedded intelligent applications. This open platform, the SymBot, is a rugged hardware and software device. The platform complies with open standards for industrial automation and systems interoperability. The SymBot platform is capable of providing advanced real-time decision support at the device level, and is designed to be remotely configurable. Applications being developed through the Pando project include engine monitoring, a dynamic load weighing system, machine location monitoring and automated activity monitoring including production and maintenance reporting.

Oct 1, 2010

By J. Hendry, K. Brady, J. Yorzyk

Drawing from the experience of nickel, copper, aluminum and mineral borates, this paper illustrates the business value that the mining, minerals and metals industry as a whole can gain from applying life cycle assessment (LCA) to products and operations. Through the use of case studies, the paper explores how companies and industry associations have used LCA to their advantage: from evaluating capital investments, meeting customer information needs, supporting new product applications, and developing credible marketing information on the environmental performance of their products. It also explores the dynamics of LCA adoption and integration within companies, and provides recommendations to further strengthen institutionalization of LCA.

Jan 1, 2010

By Alan A. Barton

Introduction The Little Long Lac mine is situated in the Thunder Bay mining district, township of Errington, Ontario. The mine is located on the south side of the most westerly bay of Little Long Lac. The property consists of 36 claims, which comprise some 1,400 acres. This group of claims was staked in August, 1932, by Tony Oklend and Tom Johnson, and, after surface sampling, was optioned by the present controlling interests, who diamond-drilled it during the winter of 1932-33. In early spring, a small steam-driven plant was installed, and shaft sinking commenced on June 1st, 1933. During the summer, all supplies are transported to the mine from Hardrock station, at mileage 18 on the Canadian National Railway line from Longlac to Port Arthur. At Hardrock, which is seven miles from the mine, the railway skirts a bay of Little Long Lac, and supplies are loaded directly from railway cars to scows. Two scows are used, of 30-and 45-ton capacity, respectively. A 36-ft. pointer, powered by a 35 h.p. engine, is used as a tug. A good winter-road has been cut out from Geraldton to the mine, for winter transportation. Geraldton is about two miles north of the mine, and is also located on the Canadian National railway. A hard-surface road is now being constructed for summer as well as winter use. Geology The Little Long Lac gold area covers the northern limits of a large synclinal structure, the contact of the Keewatin flows and sediments, striking about twenty degrees north of west, with the dip of the sediments varying from eighty degrees north to seventy degrees south, the average being around eighty degrees south. The vein worked by Little Long Lac Gold Mines occurs in massive sedimentary rock of about the composition of arkosic or quartzitic greywacke, and consists of a shear-zone up to fifteen feet in width, striking N.75°E. and dipping steeply to the south, which has been filled by numerous narrow, parallel quartz veins and. veinlets. These are well mineralized. with arsenopyrite, pyrite, and some chalcopyrite and stibnite, and carry considerable quantities of visible gold. They show more than one age of quartz deposition, the quartz being fractured and re-cemented. The arkosic rocks separating the veins and veinlets are also slightly mineralized with pyrite. Work to date has indicated the probability that the vein-shear is controlled by local drag-folding.

Jan 1, 1935

By H. Wotruba, J. Heizmann

"The use of shotcrete is a mandatory means for rock support and therefore for safety in many underground mining operations. If shotcrete gets into the flotation feed though, it can negatively influence the flotation process. This especially occurs when sublevel stoping, cut-and-fill or room-and-pillar methods are applied because as the mining face moves on, formerly applied shotcrete layers are mined together with the ore.As shotcrete does not differ significantly from fluorspar ore in its physical properties it gets moved through the comminution process and is fed to the flotation plant like the ore. To prove the influence of shotcrete on the flotation process, a laboratory test series was conducted at the Unit of Mineral Processing (AMR) of the RWTH Aachen University. The shotcrete grade of the flotation feed was varied between 0 and 10% through addition of pure shotcrete. Flotation parameters and also reagent dosage were held constant apart from the addition of the pH regulator, which was dosed to reach a constant pH of 8 at the flotation start. Results showed that with increasing shotcrete grades in the flotation feed the fluorspar recovery as well as general mass recovery decreased. The enrichment factor of Fluorspar also decreased with increasing shotcrete grades in the feed.In an effort to eliminate the shotcrete contamination of the flotation feed, a feasibility study for use of sensor-based sorting prior to the comminution process was conducted. Rock sorting not only reduces the bad influence of shotcrete on the flotation process, but also reduces comminution costs. INTRODUCTIONShotcrete is used in underground mining on a regular basis. It is used for rock support and therefore to increase safety in the underground mining environment. In mineral processing the presence of shotcrete can cause difficulties for example in the concentration processes. In flotation the highly sensitive reagent mixtures can be disturbed by the chemical activity of shotcrete and therefore recovery rates and selectivity of the process can suffer.Shotcrete is a special form of concrete which is applied pneumatically with high velocities and is compressed by its impact energy. Since the process is especially suitable for work in difficult environments and overhead areas, it is established in underground mining for many years. Shotcrete is not only applied in pre-processing of the mines, but particularly of use for cut and fill, as well as room and pillar mining methods. There it is used to secure excavation chambers. When the mine face is secured with shotcrete and subsequently the mining continues, the applied shotcrete will automatically be mixed with the ore."

Jan 1, 2016

By Mario A. Morin

Mine design, planning and scheduling is a very complex, iterative process comprising several interrelated and interdependent activities. Understanding how this process works, identifying the critical pieces of information and the decisions to be made is key to initiating business process improvements (BPI) or business process reengineering (BPR) activities. Fundamental to most BPI and BPR work is some form of systems analysis. Structured Analysis is a powerful systems analysis technique that is well suited for modeling and analyzing complex process activities. Through a series of diagrams, this paper presents a vertical slice through the analysis work performed for formally describing the underground hardrock mine design and planning process. These diagrams illustrate how simple graphic constructs can be used to decompose the most complex situations into easily understandable diagrams that facilitate understanding, communication, improvement and reengineering.

May 1, 2002

By O. Espinoza Ortega, S. Song

A process scheme has been devised to improve the silver recovery and the grade of concentrates from the scavenger concentrate of a silver ore flotation circuit. Based on modal analysis studies it was found that silver sulfide minerals in the scavenger concentrate were associated as simple binary particles and finely disseminated in sulfide and non-sulfide gangues. Fine grinding of the concentrate improved the grade-recovery curve of silver to a very limited extent owing to heterocoagulation between liberated fine silver sulfides and coarse particles of gangue. This heterocoagulation phenomenon was prevented by grinding the concentrate in the presence of the dispersing reagent sodium hexametaphosphate. The silver grade-recovery curve was improved by practicing. before the conventional flotation step, a selective aggregation step for the fine silver sulfide particles using the non-polar oil kerosene, the sulthydryl collector Aerophine 3418 and conditioning the pulp under strong agitation conditions.

Jan 1, 2004

By C. Caballero, K. Itagaki, P. Morales, A. Moyano, J. Font

Codelco-Chile is considering different processing options for the new projected concentrate from the Alejandro Hales mine. This concentrate is featured by its high arsenic content of up to 6%. Thus, it is important for Codelco Norte Smelter to define the technical feasibility for processing this high-arsenic bearing concentrate in its main smelting unit as it is the Teniente Converter, which beside of its dual feeding system can enhance the arsenic removal by volatilization. The present paper which is a part of an extensive research work will focus in the performed industrial scale test for processing about 7,000 tonnes of a high-arsenic bearing concentrates in the Teniente Converter at the processing rate of about 2,300 tpd. The impact on the chemical quality of the produced high grade matte will be discussed, and the effect of the As removal by increasing the Teniente Converter processing rate of concentrates up to 3,000 tpd when producing 70% Cu in the white metal will also be addressed.

Jan 1, 2007

By Gustavo Angeloci

Artisanal mining is a rudimentary activity that today attracts over 30 million people in virtually all developing countries around the world. As the price of gold has steadily increased over the past decade, 15 million people have become involved in extracting this metal in 55 countries. Individuals have switched to mining from primary industrial sectors such as agriculture to increase their income. These workers generally have little capital, low education levels, and no previous experience in mining. Together with a lack of technical support from governments, these factors lead to disorganized and informal mining activities that generate environmental and social chaos. The absence of technical knowledge and capital has caused a proliferation of Gold Ore Processing Centres (GOPCs) around the world established by local entrepreneurs, who provide a way for miners to process their ores using amalgamation for a fee that is relatively low to non-existent. Gold recovery by the independent miners rarely exceeds 30 % and gold-rich tailings are left at GOPC facilities as a form of payment. GOPCs recover around 90 % of the remaining gold using cyanidation, flotation, and amalgamation, without any compensation paid to the miners. In processing these mercury (Hg)-contaminated tailings, Hg cyanide complexes are produced that are dumped into aquatic environments, leading to rapid bioaccumulation of Hg by fish. In the town of Portovelo, Ecuador, the establishment of partnerships between GOPC entrepreneurs and artisanal miners has proven to be successful in forming legal small-mining companies to create more equity and reduce pollution. About 108 GOPCs operate in Portovelo-Zaruma, with 40 % of these still working illegally without proper regulation and permitting. Over 20 % of these GOPCs continue to use grinding, concentrating and amalgamating of the gold, with 58 % performing cyanidation of tailings and/or gravity concentrates, and 15 % combining flotation with cyanidation. About 94 % of the GOPCs concentrate the ore prior to applying amalgamation, which significantly reduces Hg emissions to the environment. Incorporating flotation has given the operators increased skills in mineral recovery, with the side benefit of producing a copper concentrate as added value. Despite these innovations, mineral recovery is still inefficient, and waste management is a major challenge in creating true sustainability in this sector (technical efficiency together with social and environmental responsibilities). Further organization, training and capacity-building are needed. The principles of Lean Manufacturing Methods ("Just in Time" production and "Automation") are suggested as possible techniques to assist small GOPCs to become sustainable. In this concept, a larger mining company can become associated with artisanal miners in a partnership to provide training and investment for exploitation of small deposits that would be infeasible as a single large operation. As well, an International Training Centre for Artisanal Miners (ITCAM) is being established in Portovelo with collaboration of the Government of Ecuador to further enhance and upgrade mining activities in this region. ITCAM will provide artisanal miners with technical, business and environmental training to become responsible small-scale miners. In building this new capacity, ITCAM intends to create an atmosphere of trust to attract private and corporate investors to become partners with artisanal miners.

Aug 1, 2013

By Larson. William

What is Lunar In-Situ Resource Utilization (ISRU)? ISRU involves any hardware or operation that harnesses and utilizes ?in-situ? resources to create products and services for robotic and human exploration In-Situ Lunar Resources ???Natural? Lunar Resources ??Discarded Materials Lunar ISRU Products and Services ??Excavation, Site Preparation, and Outpost Deployment/Emplacement ??Mission Consumable Production ??Outpost Growth and Self-Sufficiency Benefits of ISRU ??Increased science and exploration hardware (instead of consumables) ??Increased safety, crew exploration time, and self-sufficiency ??Technology spin-in/spin-offs help recycling on Earth & space economy

May 1, 2009

By K. Trapani

"The study undertaken aims to investigate an ice stope heating and cooling system for its potential to be implemented in sub-arctic mines, as a low carbon alternative to conventional natural gas and refrigeration chiller systems. Its performance was simulated for a years’ worth of data, taking into consideration hourly temperature data. Results showed that to supply the required heating and cooling loads, the ice stope system had to supplement its heating with natural heating. The techno-economic performance of this system was compared to that of a conventional heating and cooling system in a mine, with the ice stope thermal storage system hawing the lowest annuitized cost and significantly lower carbon emissions.INTRODUCTIONConventional heating and cooling, in a mine is implemented using natural gas heaters and chiller refrigeration systems respectively. This results in a significant portion of energy consumption in underground mines attributable to ventilation (De Souza, 2015), including the conditioning of the air to ensure that temperatures do not exceed work comfort standards (ACGIH, 2011). Especially at depth where heat could become a significant issue. An ice stope thermal storage, using ice as the storage medium is being proposed as an alternative to provide the heating and cooling—with the ice creation resulting in heating and the ice melting providing the cooling required. A techno-economic investigation of the two systems is undertaken to identify the capital and operating costs for the two systems, and to assess the ice stope’s potential to be considered a low cost and carbon solution for heating and cooling of mines in sub-arctic climates.NATURAL STORAGE SYSTEM – CONCEPT DEVELOPMENTThe concept for the natural storage system is developed from the ice stope at Frood-Stobie Mine, ON, Canada (Stachulak, 1991). The ice stope was developed for mine air heating, with the heating occurring by spraying warm return service water onto the cold intake air—resulting in the air temperature increasing and ice being created in the stope. In summer this ice was melted by passing warm air on top of it, resulting in slight cooling of the air but no significant temperature difference which could allow effective cooling. A schematic of the Frood-Stobie Mine ice stope is provided in Figure 1."

Jan 1, 2019

By R. Salimi

Tricalcium aluminate hexahydrate (TCA) is used as filter-aid for security filtration in the Bayer alumina process. TCA is typically produced on-site by mixing Bayer liquor with slaked lime. Specific properties are required from the TCA to ensure adequate filter throughput, lifetime and importantly effective reduction of solid/colloidal impurities from the solution. The effect of reaction time on morphology and particle size distribution of tricalcium aluminate was studied for a batch experiment at simulated process conditions. It was found that reaction time plays a critical role on the morphology, crystal structure (diameter and crystallinity) and particle size distribution. In the early stages of the reaction, nucleation dominates the crystallization process followed by growth dominated by agglomeration up to a mean particle size of 10 µm. The particle morphology shifted from an irregular shape to more spherical throughout the course of the reaction.

Jan 1, 2014

By E. Dalgaard

During linear friction welding of titanium alloy Ti-5A1-5V-5Mo-3Cr (Ti-5553), the weld zone exhibits beta (B) grain refinement and alpha (a) phase depletion that have the combined effect of deteriorating the mechanical performance of the weldment. In this work, linear friction welded Ti-5553 was subjected to pre- and post- weld heat treatments in order to determine the conditions under which a phase depletion could be mitigated in the weld zone and thermomechanically affected zone (TMAZ). The mechanical response of the welded samples to the heat treatments was determined by performing tensile testing at room temperature. While the pre-weld heat treatments had no significant effect, the post-weld heat treatments were instrumental in restoring the strength of the starting (heat-treated) material.

Jan 1, 2011

By Jason Mewis

Do you have it figured out? ? If so, I want to network with you! ? There?s a lot to learn as an industry The more we share the better we?ll all become at dealing with this subject If you don?t have it figured out ? You?re among the majority in the in0dustry ? Project Risk is a broad and complex issue that is dealt with through many processes ? And it?s not intuitive either ? And you don?t want to confuse one process with Another

Nov 1, 2011

By P. G. Lazenby

This paper describes the latest instrumentation improvements in the INPUT Airborne E.M. System, particularly the new electronic signal-processing techniques. Several anomaly examples illustrating these techniques are shown.

Jan 1, 1973

By A. Kowalski

This paper presents methods of implementation and the added value that can be achieved by connecting personnel tracking systems and alarm-broadcasting systems. The authors point out the functions of the two systems that enable cooperation between them. Methods for connecting the systems on the surface and underground areas of mines require some intervention in both systems, so the authors point out a possible phased approach to introducing cooperation methods. Due to the fact that tracking systems in Polish mines are at an early stage of implementation, the article aims to provide new functionality, attempts to identify the needs of future users, and describes the experience of both production companies in terms of the development of cooperation methods.

Aug 1, 2013

By G. Ozbayoglu, Z. Ozdemir

Turkey is the main boron minerals producing country in the world. The most important boron minerals are tincal, colemanite and ulexite. All mining, beneficiation and handling operations generate fines which cause ecological and economical problems. Utilization of this accumulated material requires both upgrading and agglomeration. The aim of this research was to exploit the ulexite fines by improving their grade and size. Attrition-scrubbing followed by washing and screening was employed for upgrading the fines. It was found that the grade can be increased from 23-25% B2O3 to 29% B2O3 with 73% recovery. Briquetting was applied as the size enlargement process. During the briquetting, the effect of moisture content, pressure, amount and type of binder, and drying on the quality of briquettes were investigated. The tests showed the possibility of production of strong briquettes by adding water alone, but the briquettes had no resistance to abrasion and water. Binders, namely boric acid and borax have been added to improve the properties of briquettes. The results showed that the compressive strengths and abrasive resistances of briquettes obtained with both binders were acceptable. However, the briquettes have no water resistance properties.

Jan 1, 2004

By Zhao-shu Sun, Mao-lin Li, Rui Cui

"Fankou Mine produced pyrite concentrate (PC) from the tailings by rougher and scavenger flotation before 2010, with the averaged S grade of 40.54% at recovery of 79.34%. The economic value of PC increases with its purity. When the S grade of PC feed to sulfuric acid plant is over 47%, the pyrite cinder can reach a high Fe grade of 62% which can be directly sold as iron concentrate. On this background, engineers in Fankou Mine set the PC with S grade of 47% as target.The direct way to reach that goal was to clean the rough PC Lots of cleaner flotation tests were conducted and the balanced strategy was to produce two ranks PC with the S grade of 47% and 38% at the recovery of 44.20% and 36.17%, respectively. The dual-product flowsheet was successfully industrialized in 2010. In order to further improve the quality of PC, gravity separation was introduced into the flowsheet. The numerical simulation and tests were performed to evaluate the beneficiation and classification performance of hydrocyclone as it treated the rough PC. It was shown that the underflow of hydrocyclone could addressed the S grade of 47%, and the finer size overflow could also be enriched to PC with S grade of 47% by flotation, due to the contained pyrite with well liberation. That is to say, with the ingenious addition of hydrocyclone to treat the rough PC, single PC with S grade of 47% could be achieved. The new flotation-gravity separation flowsheet was commissioned to produce the high quality PC at the end of 2013. The averaged S grade is 47.20% at recovery of 82.26% in 2014. The two steps flowsheet improvement maximizes the enterprise benefits and leads to simple utilization of Fe in pyrite in downstream industry."

Jan 1, 2016