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By Don Runge, John T. Zeni

Cuprex Limited is currently developing a small gold mining operation in Central Australia in the Tennant Creek field. In February 1984, the company undertook a feasibility study on the project and operations commenced in August 1984. Ore reserves are located between 230 and 280 metres (755 ft and 919 ft) below surface and ore extraction required the establishment of a shaft network for access, ore hoisting and ventilation. Zeni Drilling Company from West Virginia, U.S.A. was contracted to blind drill two shafts for the project. Blind drilling was selected for various reasons, including timing which related to cost efficiency. The blind drill shaft technique has proved successful in this application and with enthusiastic and innovative support from the mining industry, will prove an efficient and cost effective means of accessing and operating underground mining projects of all sizes in the future.

Jan 1, 1987

One of the critical challenges facing the mining industry ? and not just in the United States ? is the looming labor shortage. A significant percentage of the industry?s professional workforce is, well, getting old, and many will be retiring in the next 10 years or so. This is not a new issue to the industry. It has been discussed at various industry meetings and conferences for many years. How does mining, with its largely negative public image, attract young people to mining schools? And, equally important, who is going to teach them? Mining schools, what?s left of them in the United States, are beginning to lose qualified faculty to retirements, and no one is available to replace them. SME addressed this issue during the keynote session at its annual meeting in February in Denver, CO. This year?s theme was ?Mining: It?s About the People.? Despite a blizzard that blanketed the city on the day most attendees were to have arrived, the meeting still attracted a record 7,202 people. And the accompanying exhibit sold 822 booths, also a record. The U.S. Department of Energy?s National Energy Technology Laboratory contracted with the National Academies? National Research Council to complete a study concerning the availability of skilled workers to meet the energy and mineral security requirements for the United States. The National Research Council, in turn, asked SME to collect and analyze workforce trends in these industries. The result of SME?s analysis is the report ?Emerging Workforce Trends in the U.S. Energy and Minerals Industries.? It is available on the SME website, www.smenet.org. Click on Government Affairs. While the report did not paint a completely dismal picture, there were some disturbing results. It concluded that within 20 years there will not be a sufficient number of skilled professionals to satisfy the labor demand. That said, the report said that most of those positions would likely be filled. However, the U.S. mining will go through a period of time when the workforce will be made up of very young and senior workers.

Jun 1, 2013

By John Kvinsland

"The Block 43 Project is the future home of the Paul Allen Institute for Brain Science located just off the southern shore of Lake Union in Seattle, Wash. The South Lake Union (SLU) district experienced considerable development over the last 10 years and Vulcan, Inc., which is headquartered in Seattle, is at the forefront of this transition. Once a light industrial/residential location, SLU has transformed into a hub of medical technology comprising new residential units and mixed-use buildings. Malcolm Drilling Company, Inc. constructed four shoring projects for Vulcan in this vicinity over the last year, beginning with Vulcan Block 44, which consisted of 42,000 sq ft (3,902 sq m) of soldier pile and tieback wall to support a below-grade parking facility. Block 44 construction began in February 2013 and ended in mid-April. The feature project, Vulcan Block 43, was in planning stages at the time and began construction in late fall 2013.Awarded by GLY Construction of Bellevue, Wash., in September 2013, Block 43 was the most complex of the block projects performed by Malcolm. Block 43 featured dewatering and ground improvement components along with a water-tight secant pile wall. Following the commencement of Block 43, Malcolm also began work on Vulcan Block 52 in December 2013. Block 52 consisted of 43,000 sq ft (3,995 sq m) of conventional shoring in conjunction with dewatering of 8 ft (2.4 m) of excavation located below the water table. The final Vulcan project was Block 45, which started in January 2014 for Turner Construction of Seattle and consisted of 41,000 sq ft (3,809 sq m) of conventional shoring and required dewatering to complete the final 15 ft (4.6 m) of excavation.Scope and Subsurface ConditionsBlock 43 involved a wide variety of drilling applications for the building to be constructed and properly founded. The primary scope of work involved shoring support for an underground parking structure requiring excavation of approximately 82,000 cu 3 yds (62,694 m ) of soil. The cuts for the excavation were up to 43 ft (13.1 m) in depth, and the excavation was bounded by city streets as well as the South Lake Union Light Rail on its perimeter. In order to excavate beneath the water table, an extensive, deep dewatering system was required to drain the upper fill and reduce the impact of the pressurized aquifer located beneath the excavation. In addition, drilled rigid inclusions, along with compaction grouting, were required for foundation support of the future structure."

Jan 1, 2014

Block caving is the lowest cost underground mining method but it has relatively high risks and a high up-front capital and development cost. It has application to large, often lower-grade orebodies where high production rates can provide good returns on the investment. However, it has a range of technical risks that are peculiar to block caving and the usual financial, political and environmental risks that may be exacerbated by the long lead-in times associated with the development of a block cave operation. With initial development costs that may be $100 M to $1000 M when the building of a treatment plant is also required, it is obviously important to minimise and manage the risks. In a greenfield project, commitment to a substantial proportion of the capital expenditure may be required to gain access to the deposit, and the decision to proceed at this stage would be based very largely on interpretations of drill hole data. In established mines the data may be supplemented by geological mapping and past experience, etc. The quality of this data is critical and yet it is frequently degraded through poor techniques and avoidable omissions. The final decision to proceed would be assessed on projected commodity prices, mining capital and operating costs, dilution and run of mine ore grades. The latter will vary over the life of the project and these can be estimated with drawdown or draw control modelling techniques. In this modelling, there are further risks in the assumed modelling parameters or that the modelling technique may not be applicable or appropriate. The paper addresses the most critical technical and operational risk areas and provides some practical precautions that can be taken to reduce these and improve the reliability of the geological and geotechnical models.

Jan 1, 2000

By David D. Rabb

Under the auspices of the Atomic Energy Commission, the Lawrence Radiation Laboratory of the University of California analyzed an experiment to provide information as to whether the chimney of broken rock produced by a deeply buried nuclear explosive could be "drawn" by conventional techniques. Since many low-grade disseminated ore-bodies occur in a granite media, the experiment took place in a granodiorite-quartz monzonite intrusive porphyry in the Nevada Test Site as a follow-up to the Department of Defense's Hardhat detonation in February 1962. For emplacement of the nuclear device, a 12 ¼ - in. pilot hole was reamed to a diameter of 44 in. and a depth of 950 ft in one pass using a Hughes multiple-cluster rotary bit. It was then cased to 36 in. ID. The center of the explosive device was located 938.85 ft below the collar. The yield of the device was predicted to be 5 kilotons, or an equivalent of 5000 tons of TNT; the yield was later confirmed by chemical means to be 5.4 kilotons.

Jan 3, 1964

By G. Rong, W. Du

Stability of some potential unstable blocks in the left bank slope of Baihetan hydropower station is evaluated in this paper using the three-dimensional (3D) limit equilibrium method. The Baihetan hydropower station is in the downstream of Jinshajiang River, China. The geological condition in the river valley is complex, and many large discontinuities are detected in the slope of the two banks. As a result, much attention should be paid to the stability of the slope in the feasibility study stage. Because the left bank slope is an oblique consequent one, we mainly focus on the slope stability analysis in the left bank. Comprehensive geological exploration is conducted in the studied area and the detected discontinuities are well researched. By building a 3D geological model of the left bank slope, three potential unstable blocks which are close to the dam site are detected. An irregular wedge analysis method is then used to calculate safety factors of the three blocks under three conditions, which are natural condition, rainfall condition, and seismic condition, respectively. It is found that the safety factors of the block 1# and the block 2# are quite low when compared to the suggested values. Extra care must be exercised when excavating the slope near the block 1# and the block 2#. A preliminary reinforcement is also suggested.

Jan 1, 2015

By Ankit Jha, Javad Sattarvand, Aaron Young

Blockchain technology is one of the prominent disruptive technologies that are being implemented in several disciplines. The application of blockchains in the mining and mineral industry can provide utility to several processes especially when the industry is undertaking digital transformation. The governing principles of blockchain technology are applicable in undertaking transformation in several processes within the mining industry. This study investigates the applications of blockchain technology within the realms of the mining industry and identifies key areas of implementation. A systematic review of publications on academic platforms relating to blockchain technology in the mining industry did not retrieve a considerable number of articles. Consequently, a thorough review of white papers and articles authored by individuals on use cases within the mining industry is compiled and presented in this review article. This review article identifies all the potential areas within the mining industry where blockchains could provide value and improve processes through their implementation. The broad area of implementation of blockchains includes supply chain, traceability in spares parts, contract management, regulatory compliance and cybersecurity.

Mar 1, 2024

By A. Belleau, F. Lavoie

"Quebec Iron Ore Limited (QIO), a subsidiary of Champion Iron Limited (Champion), secured assets in early 2016 from the previous Bloom Lake operations in the heart of the Labrador Trough region of Northern Quebec, Canada. A plan was developed to bring the Bloom Lake facility back in operation once the iron ore market conditions improved. The project restart involved several aggressive moves to change operational effectiveness, one of which was the utilization of the existing Phase 1 Plant with an upgraded process flowsheet and equipment. The production target was 7.4 million tonnes per annum of 66% iron ore concentrate with an approximate 10% increase in iron ore recovery. The Phase 1 upgraded flowsheet was initially based on review of historical Phase 1 data and pilot testing data undertaken during the original Phase 1 operation and was finalized once additional metallurgical test work and process modeling was carried out by Mineral Technologies in late 2016. The final upgraded flowsheet is comprised of rougher spirals, rougher middling scavenging spirals, and an up-current classifier (UCC) with overflow scavenging spiral stage. A portion of the gravity circuit tailings treated by a series of wet high intensity magnetic separators (WHIMS) to boost overall iron recovery. This paper will describe the efforts taken to test and design the Bloom Lake Phase 1 upgraded flowsheet and report on the plant performance since commissioning in first quarter of 2018.SITE HISTORY The Bloom Lake iron mine property is located approximately 13 km north of Fermont, Quebec, and 10 km north of the Mont Wright iron ore mining complex, property of ArcelorMittal Mines Canada. The Bloom Lake mine facilities include a 32 km railway to efficiently transport the high-quality iron concentrate to a loading port located in Sept-Iles, Quebec. The Bloom Lake property was first explored in 1951 and went through multiple minor exploration campaigns by different companies up until 1998. A major exploration program was conducted by Quebec Cartier Mining (QCM) in 1998. This program included line cutting, surveying, diamond drilling, geological mapping, mini-bulk sampling, bench-scale preliminary metallurgical test work and preparation of a “mineral resource” estimate."

Jan 1, 2019

By S Nowosad, A Binder, O Langefeld, M Bothe-Fiekert, F Apollo

The mining industry faces complex and urgent challenges driven by an increasing demand for raw materials, and a socially demanding globalised world. The extraction of primary raw materials is today more important than ever as one of the cornerstones towards a sustainable future since the increasing demand for the raw materials required for the energy transition. In the last three years, leading countries as USA, China, Canada, Australia, and the European Union (EU) have developed and adopted strategies to enhance domestic extraction capabilities, diversifying sources, fostering innovation in recycling, and promoting international collaboration related to critical raw materials. On 2022, the Inflation Reduction Act was signed into law in the USA, in June 2023, the Australian Critical Minerals Strategy 2023–2030 was published and in March 2024, the Council of the EU adopted the European Critical Raw Materials Act. On the other hand, raw materials extraction is facing higher environmental and safety standards and regulations, as well as scrutiny from the broader public. Regrettable environmental accidents as tailing dam failures or acid mine drainage occurrences have led to a general distrust of mining activities leaving mining companies with the dual imperative of increasing output while implementing sustainability, decarbonisation, and circularity as a core value in their production processes. This challenging environment offers the opportunity to enhance ‘blue mining’ (BM) as a sustainable holistic approach that integrates the principles needed to plan sustainable, reliable, and responsible mines for today’s and future generations by implementing the principles of circular economy (CE). This requires a fundamental shift from the traditional linear economy approach to a sustainable, circular economy strategy. At its essence, BM encapsulates four crucial aspects – energy, ergonomics, water, and circularity and integrates these four aspects into integrative mine planning, defining clear goals and objectives from the ‘blueprint’ of a mine towards a beneficial post-mining activity. Its implementation can lead to maximisation of resources beyond the life of the extractive mine and sustainable use of materials by integrating the principles of circular economy and multiuse mine, see Figure 1. These concepts complement and recognise the need to minimise environmental and social impacts while advancing economic development. Finally, this contribution explains the requirements and challenges of moving from linear to dynamic planning approaches under the BM concept. This way, BM stands as an approach that can contribute to the mining industry receiving necessary approvals and support from society leading to a long-term transformation of the industry’s image.

Sep 1, 2024

By Angela Binder, Mareike Schubert, Yichen Jiang, Sandra Nowosad, Oliver Langefeld

GermanyINTRODUCTIONThe mining industry is currently characterized by various factors such as environmental impact, resource scarcity, social responsibility and geopolitical uncertainty. The production of minerals required to meet the demand for renewable energy is expected to increase by 500 % by 2050, particularly for critical minerals such as graphite, lithium and cobalt 1. Easily accessible deposits are often depleted, meaning that deeper and more complex deposits need to be developed. Furthermore, investors’ value systems have shifted towards more sustainable practices. Alternative approaches to solving this problem are therefore currently being developed, such as the Modular Mining Systems concept for scalable and adaptable mining projects 2. Many mining companies have also taken important steps to become more sustainable, implementing measures such as proactive closure strategies, restoration programs and the development of renewable energy projects. In the European Union, laws such as the Critical Raw Materials Act and the Net Zero Industry Act support the mining industry 3,4. They see it as important for the energy transition and promote more sustainable ways of working in the industry Particularly negative environmental impacts such as land degradation, scarcity of local water resources, water pollution and greenhouse gas emissions are ingrained in society’s memory. Despite these efforts, the public image has not yet changed. To change this perception, the industry must strive to better communicate its sustainable practices and the steps it is taking towards a more responsible and sustainable future, promote transparency and build trust.Digitalization, automation and electrification are driving the digital transformation in mining. However, their implementation can lead to higher capital expenditure, limiting their adoption across the industry. Furthermore, implementing new technologies can be a daunting task for any organization. Change management comes into play when introducing such disruptive technologies. It involves preparing an organization for change, potential resistance and establishing effective communication. This helps to ensure that the implementation is successful and the benefits of the new technology are maximized. Digital transformation requires well-trained, young mining, electrical, mechatronic and software engineers with a deep understanding of information systems. Unfortunately, the industry faces the enormous challenge of attracting this younger generation, who have little interest in the extraction of raw materials. The need for action is compounded by an aging active workforce heading into retirement and the forecast of increasing demand for critical minerals.In this challenging environment, the concept of Blue Mining with its constant further developments represents a promising approach. This implies a shift from a linear to a sustainably oriented circular economy. For the mining industry, this specifically means the introduction of innovative technologies, the increased recovery of materials from waste and the consistent questioning and application of circular principles along the entire life cycle of a mine. Such a change can not only reduce the environmental impact, but also contribute to economic resilience and increased social acceptance of mining.

Feb 1, 2025

By Jeff Hopple

"Bluestone Dam in Hinton, W.Va., along the New River, is owned and operated by the U.S. Army Corps of Engineers (USACE). Completed in 1949, the dam is 165 ft (50 m) tall, 2,048 ft (624 m) wide, and encompasses a water shed that is 4,600 sq mi (11,914 sq km). The Bluestone Dam Safety Assurance (DSA) Program began in 2001, and is a multiple-phase construction project to upgrade the capacity and stability of the structure to meet the probable maximum flood event. Installing 216 high capacity rock anchors was a major feature of the work.The USACE selected Brayman Construction Corporation to perform Phase 2B of the construction modifications to the Bluestone Dam. Brayman was responsible for installing the high capacity rock anchors, which range in size from 3 to 61 strands and have a design load up to 2,145 kips (9,541 kN). Drill holes range in size from 6.5 to 15 in (16.5 to 38 cm), and required full length corrosion protection. Of the 216 anchors, 57 were installed on top of the dam to resist overturning and the remaining 159 were installed on the face of the dam at a 45-degree angle to resist sliding.To gain access to the face of the dam anchor locations, the project required dirt benches, excavations with temporary shoring, and steel platforms. To access anchors on the east and west abutment faces, the team excavated over 10,000 cu yds (7,645 cu m) of material. Support of these excavations included the design and installation of three soil nail walls with over 145 nails and 3,500 sq ft (325 sq m) of shotcrete. The project also called for a 780 ft (237 m) long steel platform to gain access to the spillway anchors. The Stratus Group designed the platform to support two 85 ton (80 tonne) crawler cranes and as many as five drill rigs that were the equivalent to a design load of 3.5 ton per sq ft (335 kN per sq m). Once the final platform design was approved, fabrication of roughly 3 million lbs (1,360 tonnes) of structural steel began. Brayman’s in-house fabrication shop, in conjunction with Dura-Bond Industries and Advantage Steel, collaborated to fabricate and install the platform in less than five months. Flexibility in the platform design allowed for sections of the platform to be lowered as much as 16 ft (4.9 m) to provide access to anchors at lower elevations along the spillway face. In addition to the main spillway platform, Stratus Group, Brayman, Dura-Bond and Advantage designed, fabricated and installed six other unique platforms to facilitate anchor construction on various areas of the dam."

Jan 1, 2014

Safety is the No. 1 concern of any drill contractor or mine operator. Everyone in the industry knows a safe site helps stabilize operational costs and enables higher productivity. When it comes to exploration drilling, research has proven a majority of injuries are caused by the mishandling of coring rods. A driller helper will typically handle up to 50 rods per shift or up to 15,000 rods per year. With an annual 340 t (750,000 lb) in rods managed by hand, the risk of serious injury is extremely high. Because of this, the top request from the exploration industry is diamond rod handling. The Boart Longyear 4200 surface exploration drill, slated for release in 2009, will give the industry a hand-free, operationally safe rig.. Developed through the collaboration of its global drilling services and products divisions and targeted at the 1,200-m (3,900-ft) NQ market, the upcoming Boart Longyear 4200 surface exploration drill features the safest and most flexible rod management sys-tem in its class. The rig includes the industry?s first, truly hands-free rod handling system. This increases operator safety on the jobsite. In addition to the rod handler, the rig also features many new innovations that boost productivity and rig efficiency while minimizing the risk of downtime due to component failure or operator error. Boart Longyear has also included an intelligent PC-based operating system designed to allow complete drilling control as well as diagnostics reporting for the rig.

Jan 1, 2009

Using mines in Canada, Boart Longyear, a leading provider of drilling services and products, has put its Stage 3 Coring Bit to the test and each time the bit has passed the test with great success. After more than a year in the field at a major mine operation in Sudbury, Canada, the Stage3 coring bit broke life records to become recognized as the most productive design in the industry. In addition to the proven advantage seen in regular bit life increases of as much as 300 percent in some cases, the design is quickly being recognized for its cost-saving operational impact. In Sudbury, the mine operation realized actual cash savings of more than C$45,000 within an eight-month period by making the switch to Stage3 bits. For years, the Sudbury Basin team has relied on the Alpha Extended Crown bit with the Express Waterway geometry option, ordering approximately 500 units per year. This 07 COM ECEX configuration performed well in medium-hard, non-abrasive to ultra-hard, non-abrasive formations with an average bit life of 150 m (490 ft). While satisfied with the performance of the Alpha Ex-tended Crown, the team agreed to put the new Alpha Stage3 to the test. Boart Longyear?s field engineers supplied five drill sites with Alpha Stage3 bits in a 07 COM configuration. After thoroughly testing the Stage3, the results were clear. Even with the well-known performance and versatility offered by the previously preferred configuration, the Stage3 set a new standard of bit performance. The new bit maintained its cutting edge for up to three times longer than the Alpha Extended Crown, a significant performance increase when compared to the 07 COM ECEX.

Jan 1, 2009

By T. Hollingsworth

The Boddington Gold Mine, located near Perth in Western Australia, has recently completed the construction of a new process plant. An overland conveyor system was installed to convey the ore from the primary crusher to the process plant. This paper will discuss the overland conveyor?s mechanical design including dynamic analysis and the selection of primary mechanical and electrical components.

Jan 1, 2010

By Daniel Augusto Godinho de Carvalho

At thyssenkruppCSA, a positive heat balance at BOF process is faced, mainly because of low utilization of scrap and plant design. A singular logistic concept for hot metal transport between blast furnace and steel plant was established to optimize transportation and energy balance. Up to 80 kg of iron ore pellets/t steel is necessary for 340t BOF heat balance. In order to accomplish this challenge a stable blowing process, intensive operational development have been successfully executed: slopping rate reduction of 80% achieved without changing the blowing time. This paper describes steps and results of this development.

Oct 30, 2017

By Daniel Carvalho, Marcos Viana, Leonardo Demuner, Herbert Castro

Intensive process and technology improvements related to the BOF converter — the key process to increase steel plant productivity and stability — have been performed at Ternium Brazil. This paper details the road map for process developments and investments in equipment technology, as well as the results achieved. The main topics of this development are the process control and optimization systems, slag forming model, oxygen blowing pattern, end-of-blow point control and slag carryover control. The outcomes of this development are improvements in the reblow rate, end-of-blow oxidation, direct tapping, slag carryover, slopping ratio, metallic yield and lining life.

Oct 1, 2019

By Ted Nye

This paper describes a number of aspects of the design and construction of a driven tunnel which forms part of the Boggo Road Busway project. The driven tunnel is 430m long with an excavated width of 15m and a full tunnel excavation height of 8m. The first section of driven tunnel was excavated under the heritage listed Boggo Road Jail for a length of 120m. The main jail buildings and perimeter walls were built in 1908 and are of brick construction. Ground cover over the tunnel beneath the jail site varied from 5.5m to 8m and as a consequence the predicted settlement values and their potential to cause damage to the buildings were critical to determining and obtaining approval for the selected tunnel alignment. The geology along the driven tunnel alignment was very variable, providing mixed face tunneling conditions and ranging from surface residual soils to high strength rock at depth. The maximum ground cover above the driven tunnel is 20m.

By Andrea Koschinsky

Numerous hydrothermal vents occur along the Earth?s oceanic spreading axes documenting the reaction of seawater with hot magmatic rocks. The circulation of seawater through the oceanic crust, the interaction with hot rocks in the crust, and the subsequent discharge of hot metal- and gas-rich fluids into the ocean have significant implications for the cycling of material and energy on Earth. Until recently, hydrothermal activity was unknown from the Mid-Atlantic Ridge (MAR) south of the Equator where the MAR is offset by about 1000 km at the St. Paul?s and Romanche fracture zones. During a British cruise in February/March 2005, the first active hydrothermal vent field was discovered on the southern MAR at 5°S. During our follow-up cruise M64/1 in April 2005, the first samples from this vent field were recovered with the ROV QUEST (Univ. Bremen) and analyzed onboard. The high-temperature vent field is situated in a water depth of 2990 m along a line of collapse pits within a large basaltic sheet flow. A diffuse, low-temperature field occurs in a jumbled sheet flow few hundred meters to the east with warm water streaming out of cavities between lava blocks. Here we show for the first time that boiling fluids of ~400°C are emanating from sulfide-bearing vents at a depth of about 3000 m at a slow-spreading Mid-Atlantic Ridge segment. Although this segment is composed of thick basaltic crust, these fluids are dominated by hydrogen relative to methane. Whereas the active chimneys consist of pyrrhotite, chalcopyrite, and isocubanite, the mineral association hematite-magnetite-pyrite occurs in the inactive chimneys suggesting that the fluids became more reducing in present times. The high hydrogen contents and the high temperature of the fluids as well as the change to more reducing conditions are most likely related to a young volcanic eruption event some 300 m east of the hydrothermal field. The presence of hematite and magnetite may indicate that the upflow zone or even the reaction zone at 5°S used to be more oxidized then at other MOR sites, where the hydrothermal fluids are commonly buffered by the pyrite-pyrrhotite-magnetite (PPM) buffer. Consequently, high iron contents and high hydrogen/methane ratios occur in high temperature fluids from basaltic host rocks rather than being restricted to ultramafic host rocks. Faunal communities at the South Atlantic vents largely resemble those from the North Atlantic vents implying that the large Equatorial fracture zones do not inhibit or obstruct faunal exchange along the Mid-Atlantic Ridge.

Jan 1, 2005

By Harry Siewert, Tom Milner, Jack Stickney

"LocationThe Gibraltar mine is located in central British Columbia (NTS 93B/9W), 362 km north of Vancouver. Access is provided by 20 km of paved road from McLeese Lake, which lies 45 km north of Williams Lake on Highway 97. Latitude and longitude of the mine are 52° 30' and 122° 16', respectively.The total area of the McLeese Lake site is approximately 1700 ha (4200 acres). This includes the orebodies, dumps, surface drainage collection system, plant site, roads and tailings ponds.Brief Description of OperationOre is mined by open pit methods and is concentrated using conventional crushing, grinding and flotation processes. Copper and molybdenum flotation occurs at an average rate of 40 000 tons per day. Tailing is discharged to an impoundment area and the water recycled as process water. Additional copper is extracted from the waste dumps using sulphuric acid as a leach solution followed by solvent extraction and electrowinning.HistoryExploration by Gibraltar began in 1964, continuing until late 1970, at which time it was announced that the property would go into production. Construction started in early 1971, with initial production in March 1972. Target capacity of 30 000 tons per day was achieved by the end of March and is currently at 40 000 tons per day.Ore reserves as of January 1, 1998 were 184 384 000 tons grading 0.31% Cu and 0.010% MoS2."

Jan 1, 2000

By Björn Lindquist

Boliden has developed a number of specialised technologies for smelter gas handling and effluent treatment. These technologies will be described. Special attention will be given to the high-pressure venturi, Editube wet electrostatic precipitator, mercury removal processes, and two-stage effluent treatment.

Jan 1, 2002