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By C. A. Young, H-H. Huang, L. G. Twidwell

Solid particles, especially oxides/hydroxides, develop an electrical charge on their surface when submerged in aqueous solution. Parks was able to relate PZC (point of zero charge) of an oxide to its minimum solubility and isoelectric point. Dzombak has compiled an extensive database for adsorption reactions on ferrihydrite surfaces using the double layer theory. The equilibrium calculational program, STABCAL has been used to extend the considerations of Parks and Stumm. The PZC for many hydroxides, complex oxides, and non-oxides have been investigated and the results are reported in the literature. Removal of arsenic and metals by adsorption on ferrihydrite as the substrate has been computed using ST ABCAL and the computational results are compared to experimental data. Absorbents other than ferrihydrite such as aluminum hydroxide are also discussed.

Jan 1, 2005

By T. Banerjee, Y. Dumais, R. Lemire

"Agnico Eagle LaRonde produces over 300,000 ounces of gold annually, along with silver, zinc and copper by-products. The LaRonde plant consists of a conventional SAG and Ball mill circuit, followed by flotation. Load management is imperative for maintaining stability in grind size and ensuring consistency of the flotation feed. In flotation, the mass pull profiles of the cells and reagent dosage rates need to be managed to maximize recovery, while maintaining product quality. This is achieved by controlling the air, level and reagent addition set-points across the circuit. However, disturbances such as feed size distribution, ore hardness and mineralogy make it challenging to maintain efficient control using traditional control techniques. LaRonde therefore worked to develop a progressive control strategy, targeting stability and optimization. This started with a year-long instrumentation upgrade campaign, focusing on optimizing the performance and reliability of plant-wide instrumentation. The process was then optimized, leveraging AwaRE advanced controllers running in closed loop with PARC modules embedded within the PLC. The installation of 8 PFC cameras in flotation changed the flotation operation from a level and air control based strategy, to one that controls mass pull. This new control philosophy has allowed the plant to effectively manage mill load, improving grind size and providing increased throughput with better flotation performance.INTRODUCTION Background Since 2015, Agnico Eagle LaRonde has been conducting an optimization campaign to maximise the performance of plant assets leveraging instrumentation and control. The grinding and copper flotation circuits were identified as the areas having the greatest opportunities and value proposition for advanced control. A disciplined approach was followed to design and implement a progressive control solution to achieve operational excellence."

Jan 1, 2018

By B. Calver, D. J. M. Farnsworth

"As open-pit operations expanded at Pine Point, hydraulic aquifer evaluation was undertaken to establish the criteria necessary for the design of a feasible dewatering system.The extreme climate of this northern location dictated that the ore zone under extraction be rendered as dry as possible to minimize freezing effects. The design and implementation of such a system necessitated detailed hydraulic evaluation, and the problems that occurred are typical of those inherent in open-pit mining operations in northern areas.The paper describes the problem solution as approached from a mine engineering point of view, with particular reference to the practical aspects of operation and installation. The hydrological analysis used is simple and readily applicable to most open-pit dewatering problems."

Jan 1, 1969

By G. E. Viens, R. A. Campbell, G. N. Banks

A survey of the literature reveals wide differences in the procedures used in making iron ore pellets and in the properties of the pellets obtained. In this paper, the methods of production and the properties of pellets, as reported in the literature, are examined in an effort to determine what correlations exist between them. An attempt is also made to determine the levels of the properties of pellets which are considered acceptable and desirable in modern practice. M UCH has been written regarding the important changes which have been taking place recently in the iron ore industry. As the demand for ore has increased and the supply of direct-shipping ore has dwindled, tl1e problems associated with the utilization of lower grade ores ha\•e been intensely investigated and important advances in both beneficiation and agglomeration techniques have taken place. In particular, there has been a great deal of activity in connection with the pelletizing method of agglomeration. The superiority of pellets over raw ore has been demonstrated in blast furnace tests

Jan 1, 1962

By A. Allaire, J. Torrealba-Vargas, R. Welyhorsky

Early testwork was carried out to select the plant process design criteria and flowsheet selection. Additional testwork was carried out during the feasibility study to support the optimization of the plant design criteria. The test results showed that the recovery of gold was not very sensitive to grind size in the range of 75 to 105 microns. An additional result was that the presence of lead nitrate did not improve the kinetics of gold leaching. This conclusion was supported by the low content of sulphides in the ore. It was also found that the presence of lead nitrate increased copper dissolution, producing the potential for an increase of copper reporting to electrowinning, which is detrimental to the overall gold recovery process. The use of oxygen in leaching was investigated to increase leach kinetics. The results of leaching tests to compare using oxygen instead of air indicated that, due to the improved leach time, it was possible to reduce the number of leaching tanks from twenty four (24) to twenty (20).

Jan 1, 2011

By B. Tiryaki, M. Ayhan, O. Z. Hekimoglu

"This paper discusses the aspects of tracking cutters related to the computer-aided design of shearer drums. A comprehensive computer analysis of drum dynamic parameters for multi-tracking tool arrangement is not presently available, as the current computer programs mainly consider the aspects of single tracking. Despite the fact that the single-tracking arrangement is recommended for efficient cutting, some major drum manufacturers have been seen to persistently adhere to multi-tracking, probably due to a lack of information. Further studies in this field are believed to contribute greatly to the current understanding of the computer-aided design of shearer drums.A number of laboratory simulation trials and long-term underground investigations were carried out in detail on tracking cutter arrangement, and an equation required for a computer program was derived. The results obtained from computer assessment of dynamic parameters for drums with multi-tracking arrangement were found to be in accordance with those of the underground trials, indicating the validity of the equations. The procedure adopted for the computer appraisal of the shearer drums designed with a multi-tracking concept, as described in this study, is therefore recommended to be considered in the currently employed computer programs."

Jan 1, 2003

By Michael Samis

The real option valuation method is often presented as an alternative to the conventional discounted cash flow (DCF) approach because it is able to recognize additional project value due to the presence of management flexibility. However, these two valuation methods can be separated on a more fundamental level by their differences in risk discounting. Real option valuation applies the risk-adjustment to the source of uncertainty in the cash flow while the DCF method adjusts for risk at the aggregate level of net cash flow. This seemingly small difference is the reason why the real option method is able to differentiate between projects according to each project?s unique risk characteristics while the conventional DCF approach cannot. This paper provides an overview of the real options and DCF valuation frameworks and discusses the differences in risk discounting that exist between the two methods. Using grade-school mathematics, this paper clearly demonstrates how, with real options, a unique project risk discount can be calculated which is directly linked to the project?s unique risk profile. It also highlights why the DCF method fails in this regard and shows why a call to ?increase the Risk-Adjusted Discount Rate? is an incomplete solution at best. Finally, a heap-leach project and satellite reserve development project are valued with both techniques and the difference in investment conclusions is explained in terms of the risk-discounting concepts discussed here.

May 1, 2003

By B. R. Johnston, K. D. Streeter

"ABSTRACTCoal Mountain Operations is the newest of Fording Coal’s operations although it is the oldest in terms of its historical production. In October, 1994, Fording purchased the former Corbin Creek/Byron Creek Mine. The mine is located in southeastern British Columbia, approximately 150 air kilometers from Calgary, Alberta. It was first developed in 1905 and has gone through a variety of owners in its 90-year history.This paper will deal with the remobilization strategy and the mining plans for the operation which are being implemented to make this operation competitive in the world export coal market. IntroductionIn October 1994, following a due diligence process, Fording Coal Limited purchased Coal Mountain Operations from Corbin Creek Resources, an employee group which had previously owned the mine. The purchase awarded Fording Coal Limited with 100% of the assets, and control of all the coal leases at Coal Mountain.The mine is located in southeastern British Columbia, southeast of Sparwood at the hamlet of Corbin, (Fig. 1).Rehiring of laid-off employees started in November 1994, with mining activities also recommencing in November. The coal preparation plant was restarted in December with one shift, went to two shifts in January 1995, and had four-shift, full-time operation in April 1996."

Jan 1, 1997

By G. L. Palmer

"Abstract- ln 1986, anomalous sampling results for heavy minerals were obtained at various sites in Namaqualand on the west coast of the Cape Province. Drilling in 1987 at Graauwduinen penetrated up to 35 meters of heavy mineral-bearing Tertiary sands which extend several kilometers inland from the coast. The heavy mineral suite includes ilmenite, rutile, leucoxene, zircon and monazite, along with garnet, pyroxene and amphibole. Three deposits are recognized, two of which comprise the resource to be mined by Namakwa Sands Limited, a recently formed Anglo American Corporation subsidiary company.Mineable reserves in excess of 500 million tonnes have been delineated, sufficient to sustain mining for over 35 years at projected production rates. During the feasibility study, on-site investigations included test mining at various sites to assess mineability and to provide material for metallurgical testing in a pilot plant located at the site. Ilmenite produced at the mine will be smelted at a new facility to be built at Saldanha Bay . Saleable products comprise titania-rich slag, pig iron, zircon and rutile.During the exploration phase, company environmental guidelines were established and monitored. The feasibility study incorporated a Class 1 Environmental Impact Report, the contents of which were made public following the principles of the Integrated Environmental Management legislation."

Jan 1, 1994

By Malcolm Scoble, Nick Vagenas, Greg Baiden

Recent advances in underground communications technology have demonstrated the feasibility of teleoperation and automation in underground metal mines. One major challenge lies in the automation of underground mobile machines from surface, with the potential to reduce significantly the need for human involvement in underground operations. This paper reviews the evolution of underground metal mining automation, principally related to the development of teleoperation and automation of mobile mining machines. Examples of prototype systems are given and the associated benefits that have been observed are reviewed.

Jan 1, 1997

By R W. Drybrough

The program to increase production at Sherritt Gordon's Lynn Lake property, which began in 1956, included increasing the rope speed and the horsepower of the ore hoist at the "A" shaft. Because of the limited power sup-ply from the two 7,000-hp. hydroelectric plants, and the ? 3,600 hp. predicted for the combined hoisting requirements of the three production shafts, it was considered desirable to lessen the impact of this type of load on the relatively small power system by equipping all future hoisting arrangements with Ward Leonard direct-current drives. The manually operated 8-by 4-ft. hoist at the "A" shaft had a rope speed of 1000 f.p.m., and was driven by a 385-hp., 380-r.p.m. wound rotor motor with liquid rheostat control. This A.C. drive was replaced by a semi-automatic Ward Leonard direct-current drive with a 515-hp., 566-r.p.m., shunt wound motor, providing a rope speed of 1,500 f.p.m. During several months preceding the con-version, all possible preparations were carried out to keep the changeover period to a minimum, and this resulted in a total shutdown time of twelve days. The capability of the "A" Shaft hoist was increased from 109 tons per hour to 134 tons per hour, and both mechanical and electrical maintenance were reduced considerably. The total cost of the conversion amounted to $130,000. The hoistmen who had been required for the manual A.C. drive were transferred to the new Farley shaft, and the reduction in operating labour costs of the "A" Shaft hoist

Jan 1, 1965

By Deborah A. McCombe

"There are a number of important dates that must be disclosed when a Qualified Person (QP) is preparing a technical report for securities purposes. The dates are discussed in NI43-101 and the Form of the Technical Report, NI43-101F1. •,Effective date of the technical report •,Possible revision date of the report •,Effective date of mineral resources and mineral reserves •,Date of the personal inspection (site visit) •,Signature date of the date report (execution date) •,Date of the certificate of the QP •,Date of the consent of the QP The effective date of the report is basically the cut-off date for the information that is included in the technical report. The effective date should be close to the signature date. If there is too long a period between these dates, the QP runs the risk of new material information becoming available and then the technical report would no longer be current. The effective date is disclosed on the title page of the report and on the signature page. If a technical report needs to be revised to correct problems or disclosure deficiencies identified by the regulators, the QP will normally need to include a revision date on the title page of the report to distinguish the revised version from the original version. In these circumstances, the regulators will request that the original date of the report remain on the title page and the revised date will be below it. When a technical report must be revised, the QP must resign and date the signature page of the report and provide a new certificate and consent."

Jan 1, 2003

By Yongbao Zhu

The Ag2O-mediated reactions of cycloaurated compounds with a general formula Au(L)Cl2 (L = bi-dentate C?N ligand) with thiosalicylic acid, N-acetyl cysteine or 1,2-benzenedithiol in DMF proceeds via ligand substitution of the Au?Cl bonds to afford the S-O and S?S adducts all in good yields. The reactivity of the dichloro, S-O and S-S adducts towards thiols were examined by reacting with cysteine in an aqueous medium, revealing that all of Au-Cl, Au-O and Au-N are labile for thiol displacement. The measurement of the inhibitive activities of these compounds against human cathepsins B and K showed that the dichloro and S-O adducts are effective inhibitors with IC50 values ranging from 0.1 to 2.6 -M, and that the S-S adducts are inactive.

Oct 1, 2003

By Anna Maria Venezia

Bimetallic Au-Pd catalysts supported on amorphous silica-alumina (ASA) with vary amount of alumina (0, 8, 14, 28 and 100%) were prepared by the simultaneous reduction of palladium and gold precursors by ethanol in the presence of the polyvinylpyrrolidone (PVP). X-ray diffraction and X-ray photoelectron spectroscopy analyses indicated formation of alloyed Au-Pd particles. Ammonia temperature programmed desorption measurements were performed to monitor the acid strength and the amount of acid sites on the catalysts after their reduction with 10%H2/Ar at 573 K for 1h. The effect of the support acidity on the catalytic activity was investigated in the simultaneous hydrogenation (HYD) of toluene (T) and naphthalene (NP) in the presence of dibenzothiophene (DBT). Coke formation was also determined. Under the selected conditions (P = 5.0 MPa, T = 523 K, WHSV = 41.2 h-1), all the catalysts were resistant to poisoning with 113 ppm of S (as DBT). The hydrogenation activity of toluene and the HDS activity of DBT were found to correlate with the concentration of the medium strength acid sites. The enhancement of the HYD activity and the S- tolerance was related to modifications of the electronic properties of the metal atom upon interaction with the Brönsted acid sites and upon intermetallic interaction.

Oct 1, 2003

By S. G. Coultis

Turner Valley is in the foothills of the Rocky mountains, at an altitude of 4,000 feet, and is 42 miles south west of Calgary. The present producing area is 8 miles long by 1 1/2 miles wide, while drilling is being carried on over an area of 10 miles by 2 miles . There are 32 wells producing, 26 wells drilling, and 17 wells shut down, making a total of 75 wells, which range in depth from 2,160 feet to 5,900 feet, varying according toa the well location on the anticline centre wells being shallower than those located on the flank. The first indication of possible production in this field was a gas seepage on the banks of Sheep river, in what is now the Royalite plant yard (Figure 1). Geologically, this seepage proved to be located on an anticline running through the valley in a southwesterly direction. The Calgary Petroleum Products Company was formed in 1912, and under the direction of Mr. A. W. Dingman, President, and associates, the first well was drilled. Production was obtained in this well. Gas was found in several horizons from 884 feet to 3,960 feet, and oil at 1,557, 2,718 and 3,839 feet. In May, 1914, oil was struck at a depth of 3,839 feet, this being a light straw-coloured oil of 60 gravity, which was blown spraying from the well accompanied by three to four million feet of gas. The latter contained some 200 grains of hydrogen sulphide per 100 cu. ft., giving it the disagreeable odour so well known in Turner Valley gas. This strike caused considerable excitement and started the famous 1914 boom, when some 400 oil companies were formed. The well referred to produced from two to five barrels of 60 gravity oil per day, and 4,000,000 cu. ft. of gas. The oil was used in the crude form in cars and trucks.

Jan 1, 1929

By Glen A. White

The level of impact and mitigating measures that are forecast in an environmental assessment (EA) for a new, or significantly modified, metallurgical processing facility or mine are taking on increasing importance during the subsequent life of the facility. The basic premise is that one is authorized to operate within the envelope defined by the approved EA. Operations inevitably change as they develop and mature, and at some point, one is faced with the prospect of re-doing the original EA work. This can lead to significant development delays. Cameco Corporation (Cameco) has played a major role in developing the northern Saskatchewan uranium mining industry over the past decade. Through the EA process, the company has developed ideas on what works well in generating approvals that give the operator some future flexibility. Early introduction of concepts for potentially different mining and processing methods, as well as contingency plans if things do not work out exactly as predicted in the original EA, can make subsequent regulatory approval for change a more efficient process. One must also preserve the principles of open consultation upon which the EA process was originally based. As such, involvement and support from local communities and other stakeholders is required to ensure the long-term success of the EA process.

May 1, 2004

The Silvermines area of north County Tipperary in Ireland has experienced mining activity for over a thousand years, with lead, zinc, copper, barite and sulphur being extracted from a series of Carboniferous limestones. The last mine to operate in the area was closed in 1993. A legacy of contamination and derelict surface structures remain. Following the death of cattle in the vicinity in 1999, a governmental Inter-Agency Group was established to conduct an investigation. The ?Silvermines Rehabilitation Project? resulted, and included a proposal for the development of a Mine Waste Management Facility (MWMF) to act as a repository for waste materials from problematic sites across the area. The nature of the setting supported an effective solution from both a cost and performance perspective; and with limited maintenance requirements. Locating the MWMF where most wastes were identified would help minimise handling and relocation of materials. This position coincided with an area of artesian groundwater pressures. The resulting MWMF design consisted of a perimeter engineered embankment with the crest elevation designed to just exceed the groundwater piezometric surface. The base would remain unlined and groundwater permitted to rise up into and saturate the contained in-situ tailings deposits and imported mine wastes. The proposed system thus benefited from the ?wet cover? approach to minimising further oxidation of wastes and metal leaching, but without the usual accompanying outward hydraulic gradient and leachate management issues. A sub cap drainage layer with downstream outlet was incorporated to prevent any possibility of hydraulic rupture following an unexpected rise in groundwater heads. Leakage rates from the MWMF were deemed to essentially be driven by surface infiltration rates alone (characteristic of a ?dry cover? approach), with the proposed composite capping system simulated to perform at an infiltration rate of less than 1 mm per year. A toe drain was incorporated with the perimeter containment system, and this collection together with diverted neighbouring drainage was directed under gravity to a dedicated Passive Treatment System (PTS). Overall, effluent water quality from the PTS has been predicted to reflect an annual mass metals removal in the order of 95% below baseline.

Aug 1, 2013

By Peter A. Adcock, Rob Fraser

Interest in monitoring nucleation overpotential in electrometallurgical processes dates back some 40 years or more. Conversely, remarkable progress has been made in recent years on describing in detail the processes involved in the formation of thin films by electrodeposition. The newer body of work underscores a need for greater clarity in speaking about the role of nucleation and in the acquisition and interpretation of nucleation overpotential measurements – the aim of this paper. In electrometallurgy, it is generally desirable to form deposits that remain smooth, compact, and relatively fine-grained while the deposit grows to a thickness on the order of 5-10 mm, about 100 times thicker than technological thin films. Hence, we distinguish two kinds of nucleation that can result in formation of new grains:- (1) initial nucleation (onto the substrate surface) of islands that coalesce into growing deposit, and (2) ongoing nucleation of new grains on the deposit surface long after the substrate has been covered and ceases to have a direct influence. Nucleation overpotential of the first type should be measured on an electrode surface truly representative of a real industrial substrate. The second type requires judicious choice of electrode material – an “ideal foreign substrate”. In general neither the industrial substrate nor native metal to be deposited is suitable for measurement of the second type of nucleation overpotential, because of interference by other processes. For the future, clear terminology is needed to distinguish these two types of nucleation potential. The second is the one for which the type of plot dubbed by Moats and Derrick as an “Adcock plot” and by us as a “Kerby-Adcock plot” was first conceived and correlated with relatively thick zinc electrodeposits. The data of Moats and Derrick showing trends for copper electrodeposition on stainless steel and on copper electrodes are interpreted within this framework.

Jan 1, 2016

By W. R. Hargrave

"Mining OperationsOre will be mined by open pit techniques. Because of the high grade of the deposit and the low strip ratio, mining rates are small relative to most other open pit operations.The ore deposit is located in the valley of the main fork of Red Dog Creek. The bulk of the deposit is located on the southwestern flank of the creek, but mineralization does traverse the creek in both the north and east directions.Erosion has exposed the orebody in a number of locations, and has resulted in oxidation of the mineralization closer to the surface. Although much of this oxide material is very high grade, it leaches readily and, at least in the initial phases of the operation, will be stockpiled and not treated in the concentrator.During construction, 2.3 million mt. (2.5 million st.) of overburden and waste will be stripped from the orebody to expose ore for initial operations. Competent non-mineralized waste will be used to build roads and waste dumps, but the bulk of material removed consists of oxide or ice-rich soils and weathered rock which is not suitable for construction.The annual ore mining rate will be 1.9 million mt. (21. million st.). The strip ratio will start off at 1.2 to 1, falling to 1.0 to 1 by year 5 and ultimately to 0.8 to 1.Bench heights are set at 7.6 m (25 ft). Pit slopes will vary depending on the material present in the wall. The slope, through competent waste and the sulphide package, was set at 45 degrees. This is flattened to 26 degrees (i.e. 2: 1) through overburden and Upper Kivalina shales. The Kivalina Shales are an ice-rich shale whose carbonate matrix has been leached out and which exhibits little or no strength as it thaws. In addition, a 100 ft containment berm will be left in the wall below overburden and Kivalina."

Jan 1, 1989

By R. Viljoen, K. Manns

"The mining industry instinctively follows rule-of-thumb design velocities often based on very simplistic theoretical “economic velocity” optimization calculations to determine airway sizes. Although these are important building blocks in ventilation planning it should be recognized that mines are far more complex and various, often opposing factors, are at play. Therefore, it is important that each ventilation situation be analyzed on a case-by-case basis to determine the best-fit solution for an operation. The ventilation design process should not necessarily be constrained by theoretical optimal economic velocities that become rules-of-thumb. In some cases, this could lead to unrealistic infrastructure requirements and exorbitant capital expenditure. This type of design often lacks corporate support leading to a scenario where no ventilation upgrades are implemented. Economic velocities typically consider the cost of power, development costs and operational risk. These typical rules-of-thumb work reasonably well as a starting off point when considering feasibility of greenfield projects. For established mines that are looking at expansion these rules may not be appropriate due to capital expenditure constraints or geotechnical ground conditions. The theoretical optimum should be reviewed in the case of an established mine where existing infrastructure could perhaps be maximized. For example, the geotechnical risk of large diameter raises at depth may require multiple small diameter raise to maintain the theoretical economic velocity. If a mine has a life of less than 5 years, then the cost of power is an insignificant proportion of the total owning cost. For these mines, operating the ventilation raises at an increased velocity to avoid a complicated and expensive capital upgrade might be the more appropriate option, even though it opposes the traditional rules-of-thumb. Mines which are capital constrained may be better off accepting a higher operating cost for the interim or settle for minor infrastructure upgrades rather than run the risk of the entire ventilation upgrade not being approved at all. This paper explores a number of examples derived from case studies undertaken by the authors for several deep mechanized mining projects in Australasia. The examples explore conditions under which higher than the economic norm would be applicable."

Jan 1, 2019