Search Documents

NANA Accepts Mining ­ 1974 - Leadership presented mining option to people ­ Community meetings; recognized need for cash economy ­ 1979 - Poll shows consensus in favor of mine development ­ 1980 - Shareholders approve mining; Congress approved land selections

May 1, 2002

By Kevin S. Borthwick

The subject of this paper is a facility wide Distributed Control System (DCS) upgrade being completed at a large copper and molybdenum mine. This paper will discuss the innovative hardware and software technologies employed in the new control system. This paper will also describe the planning process, migration path and simulation techniques used to ensure the success of such a large and complex DCS upgrade.

May 1, 2008

Ion Exchange is finding a greater role in copper processing, and hydrometallurgy in general, both as a technique for removing impurities and as a means of adding value through the recovery of secondary metals. Both the gold and uranium industries use resin adsorption as a primary production technique. While hydrometallurgical processes predominantly rely on solvent extraction as the mainstay of copper recovery there are a number of projects, in particular polymetallic deposits, which are considering the use of resin recovery as an alternative or supplemental production technique. A number of applications have been developed and proven at commercial scale for the removal/control of impurities (iron, antimony and bismuth) from copper electrolytes. These are well documented ion exchange applications. Increasing metal values and scarcity of certain metals are focusing companies to look at secondary metals recovery rather than losing these often highly valuable metals to tails residues. Bleed streams are being seen as valuable opportunities to recover contained metals; iron, copper, nickel, cobalt, bismuth, antimony and rhenium are all metals being targeted for removal or recovery from process solutions, electrolytes and bleed streams. An overview of currently applied techniques as well as some developmental technologies for impurity removal and secondary metals recovery is presented to provide insight into the advantages and flexibility of ion exchange applications in metals processing.

Jan 1, 2007

By K. Oishi

We have developed a 76Cu-3Si-21Zn alloy "ECOBRASS®" containing no lead. When 3% Si is added to a 78Cu-22Zn alloy, kappa and gamma phases participate uniformly in the alpha matrix. When being machined, stress concentrates on these hard phases, namely kappa and gamma, and thereby lowering the required cutting force and yielding segmentalized chips without lubricant. Kappa and gamma phases transform into beta phase under high temperature, which makes it easier to extrude and/or forge the alloy. When 0.08% P and 50 ppm Zr are co-added, the grains of ECOBRASS® castings are refined significantly to become as small as several dozens of micrometers. The grain refinement by the co-addition of P and Zr improves castability, tensile strength and elongation of ECOBRASS® castings. Meanwhile, the lead leachate from an ECOBRASS® water meter, field-tested in pH 6.8 drinking water for one year, was less than 5 ppb without correction. No indication of dezincification corrosion was observed, either. ECOBRASS® is equally suitable for rods, forgings and castings, and makes it possible to produce a complete set of plumbing parts (valves, faucets, etc.) by its own. This way, not only improving recyclability, ECOBRASS® also realizes size and weight reduction due to its good corrosion resistance and high strength.

Jan 1, 2007

By Y. T. John Kwong

Abstract - To exploit an ore deposit without unduly impacting the environment is a challenge that can only be met by the concerted efforts of traditionally independent teams working on a mining project. Not only is detailed geology required of geologists to help mine engineers to develop a mine plan that assures generation of the least possible amount of mine waste, but metallurgists also have to select the most environmentally friendly mineral processing schemes, and communicate with environmental engineers with regard to complications that process chemicals may pose on proper mine waste management. Traditional ore deposit models typically emphasize the geological and mineralogical aspects of ore genesis to facilitate exploration for similar deposits. Recent research has shown that potential environmental liabilities such as acid mine drainage and metal leaching can readily be predicted according to deposit types. The choice of mining methods, mineral processing schemes, and decommissioning options are also largely dictated by the composition and setting of an orebody to be mined. Integrating such related information into traditional ore deposit descriptions would lead to the development of comprehensive environmental ore deposit models. The latter would facilitate communication among staff of the varied components of a mine project and aid with the selection of a combination of methods and strategies that would assure minimum environmental risks and impacts, reduce the overall project cost, and enhance sustainable development.

Jan 1, 2003

By U. Troncoso

Mantoverde is a heap leach-SX-EW operation that was commissioned in December 1995 at a production rate of 42,130 ton of copper per year and 5.4 million ton of ore per year. Copper production has been steadily increased to reach 62,000 ton in 2005. The forecast copper production for 2006 is 60,300 ton for an ore treatment rate of 9.5 million ton. A first dump leach operation was started in 1999 at a production rate of 1,922 ton of copper. A second dump leach operation was started in early 2002 at a production rate of 2,805 ton of copper. Dump leach production will be increased over time to as much as 24,000 ton of copper. Several improvements in the heap leach process have been implemented to cope with the higher ore throughput and copper production. However, the solvent extraction plant has remained unchanged which has resulted in a lower availability of raffinate solution and, as a consequence, in longer leach cycles. Different studies have been undertaken in order to optimize the solution management system at Mantoverde, including column test work aimed to reduce the leach cycle and solvent extraction plant modifications aimed to increase the raffinate solution availability. The test work program and the economical evaluations carried out, as well as the conclusions and recommendations obtained, are discussed in this paper.

Jan 1, 2007

By Z. -G. Ren, J. -S. Qian, Y. -G. Yang

The waste slags from chemical and metallurgical plants contain approximately wt 1% water soluble Cr6+. This hexavalent chromium is very harmful to human health, and the treatment of the slags has concerned metallurgists for many years. A sintering method was developed to treat the waste slag. In this process, sinter was made from a mixture of the waste slag containing hexavalent chromium, iron concentrate and coke breezes. During sintering, hexavalent chromium was reduced to trivalent chromium. The latter is known as a non-harmful material and can be used as chromium resource for the production of ferrochromium or chromium-containing cast iron. After sintering the hexavalent chromium in the sinter could be reduced to less than 0.0008%. It was found that the waste slag with fine particles was favourable to the Cr6+ removal. An increase of carbon content in the sintering mixture could increase the rate of Cr6+ removal and the strength of the sinter produced. The rate of Cr6+ removal increased with increasing basicity of the sintering materials with basicity less than B=1.8, above which it decreased with increasing basicity. Blast furnace was found to operate smoothly when using the sinter made from the waste slag containing chromium. However the productivity of sintering machine was slightly low compared to the sintering operation using ordinary raw materials.

Jan 1, 2004

By P. A. Riveros

Antimony is commonly found in copper electrolytes and can contaminate the cathode deposit. Several methods, such as ion exchange, solvent extraction and precipitation, have been developed to remove antimony from copper electrolytes. However, past research has been carried out almost exclusively with Sb(III), whereas the presence and behavior of Sb(V) in the electrorefining circuit have been largely ignored. In this study, the behavior of Sb(V) species was monitored and compared to that of Sb(III) species, using specially developed analytical and SEM-EDS techniques. Significant differences in the behavior of the two species were noted. Although the solubility of Sb(III) increases with temperature in synthetic copper electrolytes, the solubility of Sb(V) appears to be constant over the range from 30 to 80°C. Whereas Sb(III) forms several crystalline oxy-sulphate compounds, Sb(V) appears to remain as an amorphous oxide. Both Sb(III) and Sb(V) are extracted by aminophosphonic resins, and Sb(III) is readily eluted by HC1 or complexing agents. By contrast, concentrated HC1 elutes Sb(V) inefficiently and complexing agents, such as EDTA and tartaric acid, do not elute Sb(V) to any significant extent. This observation implies that in industrial practice, unless special measures are taken, Sb(V) will accumulate on the resin, eventually impeding the ion exchange process.

Jan 1, 2007

By Tetsuya Yumoto, Toshikazu Shiratori

Information on the elements contained in E-Waste is important from the viewpoint of recycling. We analyzed several components of waste electrical and electronic equipment (WEEE) collected from citizens. The distributions of the minor metals in WEEE were determined with elemental mapping and chemical analyses. The annual change in elemental composition was investigated by analyzing equipment manufactured in different years. The information will be of use for separation techniques required for future advanced recycling.

Jan 1, 2011

By M. Rigaud, N. Zhou, K. Sankaranarayanane, X. Zhou

The effect of amount and type of dispersants on the rheological behaviour of bauxite-based low-cement castables has been studied in detail. The rheological properties: flow resistance and torque viscosity, as measured by a rheometer, are found to be strongly influenced by the amount and type of dispersants. In the present investigation, a mix containing sodium hexametaphosphate, at an optimal level, is observed to be theologically superior at the given experimental conditions.

Jan 1, 2004

By Anthony P. Makuch

Dynatec Corporation is an integrated mining services company, providing mine development, operations management, engineering, drilling and metallurgical services to the North American mining industry. Dynatec was the contract operator of the Ken Snyder Mine in Midas, Nevada from start of production in January 1999 to September 2001. This paper summarizes Dynatec?s experience and approach to the use of longhole stoping methods for mining to widths of 1.3 to 2 metres in a steeply dipping narrow vein orebody.

Oct 1, 2001

By H. A. Wentworth

The Central Manitoba mining district, as spoken of in Manitoba, refers to that portion of the country lying between lake Winnipeg on the west and the Ontario boundary on the east, and from a few miles north of the Wanipigow (or Hole) river on the north, to a few miles south of the Bird river. It embraces two known mineralized belts; the gold area in the north, extending from the shores of lake Winnipeg almost to the Ontario boundary (in a slightly southeasterly direction) a zone some eight or ten miles wide and perhaps forty miles long, lying (for the most part) north, and parallel to, the Manigotagan river; and the Bird river copper and coppernickel deposits, an area not yet clearly defined, but in general lying immediately north of, and roughly parallel to, the Bird river. To the south of the Bird river is a somewhat differently mineralized area, numerous pegmatite dykes being found, with minerals typically associated with such rocks. More specifically, the known gold deposits are largely segregated in the above belt; (1) around English brook; (2) along the north shore of Wanipigow lake; the Rice lake area (about midway of the belt); and the Long Lake-Bulldog lake area, at the eastern end of the belt. Not all the known gold occurences are found in these segregations, but the density of claim staking in these areas is perhaps an indication of the greater number of prospects found in them to date.

Jan 1, 1925

By J. C. Glandus, N. Tessier-Doyen, M. Huger

The Young's modulus of bi-phased model materials (vitreous matrix containing spherical alumina inclusions) have been determined by two complementary approaches: experimental and analytical. If the matrix and inclusions exhibit close coefficients of thermal expansion, the experimental results lie in the vicinity of the lower bound of the Hashin & Shtrikman's model. If there is a dilatometric disagreement between the components, untypical behaviors, similar to those obtained for a family of industrial refractory materials, were observed when the temperature varies.

Jan 1, 2004

By Mahmoud Shakeri1

Various types of thin-walled structures have been frequently used as energy absorbers to mitigate the adverse effects of impact and hence protect the vehicle structure under consideration when subjected to different loading conditions. Compression tubular structures that buckle in a progressive manner, can be used to advantage, providing inexpensive and versatile, but nevertheless weight and stroke efficient energy absorbers. In this paper quasi-static nonlinear finite element simulations are performed to study the effects of number of corners of the cross-section, wall thickness, plastic hardening rate of material, foam-filler and load angle on deformation mode and mean crushing force of tube. Crush strength increases as the number of corners of the cross-section increases, though it almost saturates for the number of corners beyond 11. Higher plastic hardening rate stabilizes the collapse pattern. Foam-filled tubes seem to have higher critical load angles in oblique loading and display a more stable and gradual decrease in mean load over the transition region. Substantial decrease in the initial peak load and dynamic load at any a given deflection was observed as the load angle increases. The investigation of bitubal arrangements and Multi-cell tubes reveals that these may be preferable to monotubal specimens due to the presence of the inner profiles. In addition, a comparison is conducted between the numerical and experimental results of the mean forces of some special angle elements. Good agreement is obtained.

Oct 1, 2011

By Patrick R. Stephenson

The Australasian Code for Reporting of Mineral Resources and Ore Reserves (the ?JORC Code?) has been operating successfully for 14 years, and has an ancestry dating back over 30 years. Together with complementary developments in stock exchange listing rules, the Code has brought about substantially improved standards of public reporting by Australasian mining and exploration companies. The Code is regarded as a world leader in its field, and has been used as a basis for the development of resource/reserve reporting standards in other countries. The reasons for its success are varied, foremost amongst them being its adoption in full by the Australian and New Zealand Stock Exchanges, and the ability and willingness of mining industry organisations to bring Competent Persons to account when necessary. The latest revision of the JORC Code was undertaken in 2002/03, based in part on releases of upgraded reporting standards in Canada, United Kingdom/Western Europe and South Africa, and the 2003 edition is expected to be released mid-year. Two of the more significant changes are: the introduction of a requirement for a Competent Person to be responsible for the documentation upon which Exploration Results are reported; and inclusion in the definition of a Competent Person of a reference to ?Recognised Overseas Professional Organisations?, being overseas professional organisations to which Competent Persons may belong for the purpose of preparing documentation for the submission of reports to the Australian Stock Exchange.

May 1, 2003

By D. Lemieux

A gold bearing pyrite concentrate was treated at the pilot scale for the extraction of gold. Mineralogical analysis of the concentrate identified gold to be mainly present in the form of a solid solution in pyrite. This gold distribution resulted in a poor extraction yield of 55% by direct cyanidation. A piloting campaign including an oxidative pre-treatment by roasting in a fluid bed was followed by treatment with halogens for gold extraction has led to a gold extraction yield of 96.5%. Sulphur removal during the oxidation was very efficient at >99.5% and gold extraction by the halogens was completed within a 1 hour contact time. The piloting was performed on a 300 kg sample and uses a diluted solution of hypohalites as the oxidizing agent for gold extraction. Sulphuric acid was injected in the reactor during the halogens treatment to lower pH to 2. The diluted solution of hypohalites (1-3%) was generated by electrolysis during the piloting campaign in a membrane-less electrolysis cell. The extracted gold was recovered over activated carbon in column and the gold depleted brine was treated for impurities removal and recycled for further gold extraction. With the recycling of water and brine, the regeneration of hypohalites and with a barren solid that is inert and stable, the Nichromet Extraction technology is a green process where the protection of the environment does not preclude profitability.

Aug 1, 2013

By A. A. Sirkeci, M. Tarkan, N. Acarkan, O. Kangal, G. Bulut

This investigation deals with the evaluation of the tailings of the Kirka Borax Plants. In this respect boron in the tailings was recovered and the utilization of the clayish fraction was investigated. There are five tailings ponds in Kirka four of which are used for the tailings of the borax concentrator and the remaining one is used for the tailings of the sodium penta-borax plant. Experiments were conducted with samples taken from ponds containing coarse fraction and fine fraction. Coarse fraction of Borax Concentrator were screened through a set of sieves. The fraction above 1 mm was removed with 41.5% recovery and 33.3% B203 content. Scrubbing was applied above 0.1 mm and products containing 32 to 34% B203 were obtained with recoveries around 35%. The tailings of sodium penta borax plant was also screened and it was found that 15% of boron reported to +1 mm size fraction with 35% B203 content. Sample containing fine tailings was treated by cycloning. The cyclone overflow was found to be below 6µm and it was separated to be used in the subsequent tests. The usage of cyclone overflow in paper, ceramics, glass, pigment and drilling industries was investigated. Since this fraction is mainly composed of carbonate minerals rather than clay minerals it was suggested that it may be used for construction and moulding purposes. Furthermore, the B203 content of the cyclone overflow was reduced to 2.4%.

Jan 1, 2004

By M. Olper

Commercial copper plants utilising current best technology are tending towards ever increasing scale, the concentrate requirements of which cannot be serviced by a single mine. In such cases, raw materials are often sourced from different mines, which are often far away from the production plant and usually with very different ore compositions. These plants tend to use the traditional thermal processing steps of smelting, converting to blister, anode refining and casting to produce copper anodes that are then refined in a sulphate electrorefining operation. These thermal steps are in some cases troublesome and require the recycling of considerable quantities of material. A new process was developed taking advantage of the latest developments of the first thermal step of the classic loop, the smelting of copper concentrate to high grade matte or white metal using the well known AUSMELT Top Submerged Lancing Technology. The white metal and/or high grade matte product is converted directly to copper cathode and elemental sulphur using the ECUPREX technology. This approach provides an alternative to the traditional thermal steps of conversion to blister, thermal refining and anode casting, which, especially at small scale, can be expensive and problematic in terms of technical and environmental concerns. At first evaluation, this new process can be operated at low capacities, thereby, changing the traditional approach to copper production. Instead of taking the concentrate to the copper production plant, the copper production plant is taken close to the mine with some significant economic and technical advantages.

Jan 1, 2007

By Christopher McElman

Real-time mine management solutions have evolved over time from closed, proprietary solutions, to a "system of systems" that may include a wide variety of off-the-shelf components and technologies. Modular Mining Systems has embraced open standards for their NextGen products to bridge the technology gaps between these systems. However, the remaining logical gaps must be overcome, in order to achieve truly seamless integration between discrete systems. When dealing with volatile real-time management problems, the effectiveness of business process modeling and middle-ware can break down. Scientific principles of military command and control applied to mining domain help to achieve better alignment and reach the highest level of integration. The combination of open standards and off-the-shelf hardware and software with a deliberately structured command-and-control approach provides a clear evolutionary path from ad-hoc connected systems towards real-time management of a seamlessly integrated digital mine.

Oct 1, 2009

By G. L. Spence

Prevention of cuprous and cupric oxide formation on stored ETP copper rod is a major concern for copper rod and wire producers. During normal storage periods copper oxide layers can increase from less then 100 A to more then 1000 A exceeding ASTM specifications and discoloring the rod surface. Various types of corrosion inhibitors are tested and compared in effectiveness for prevention of copper oxide formation on stored copper rod. Aromatic triazole compounds are also compared to a non-azole containing compound.

Jan 1, 2007