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Sherwood?s Minto Project ? High grade copper copper-gold deposit ? Yukon Territory, Canada ? Development underway ? Permitted ? Production by mid mid-2007 ? 40 40-50m lbs Cu plus Au/Ag by by-products ? Parallel exploration program underway ?Discover more high grade resources ?But what kind of deposit is it?

May 1, 2006

By S. V. Ulianov, A. Y. Senchenko, A. A. Shvets, A. V. Aksenov

Development of an efficient technology to process complex ores containing gold and antimony as well as silver is described in the paper. The results from the testwork aimed at the valuables recovery by means of flotation are presented. A process sample of antimonite gold-bearing ore was studied in TOMS institute aiming at development of a technology to process such an ore with generation of antimony concentrate and sulphide gold-containing concentrate. Material composition study indicated that the ore included 5.3% of sulphides: arsenopyrite – 2.4%, pyrite -2.4%, and antimonite – 0.5%. Gold is present as an isomorphic dissemination in arsenopyrite. At sighter testing stage a direct selective flotation flowsheet was chosen to process the ore. Antimonite flotation was activated due to addition of lead nitrate. A single cleaning of a rougher flotation concentrate resulted in antinomy concentrate with 30% Sb content and 71% recovery. Au recovery into antimony concentrate did not exceed 1%. Sb flotation tailings were used to float the remaining sulphides and gold. The resulted sulphide concentrate was characterized by Au content of 20 g/t at about 80% recovery, arsenic content - 10% at ~80% recovery, and sulphur content - 18% at ~81% recovery. The sulphide concentrate can be forwarded to further processing aiming at gold recovery. Given that the concentrate is highly refractory it should be pretreated (bacterial or pressure oxidation, Albion process) prior to cyanidation in order to liberate gold from sulphides. The proposed technology allows one to solve the problem of precious metals recovery from antimonite ores.

Jan 1, 2016

By Q. J. Xu

In blasting sensitive areas, the use of traditional blasting for rock fracture is restricted. Soundless cracking technology has been presented to achieve rock fracture instead of blasting. However, when the diameter of a borehole is larger than 50 mm, it is very dangerous that the soundless cracking agent (SCA) will have a tendency to gush from the borehole, which also leads to cracking failure. In this paper, a new large scale borehole soundless cracking technology is presented, using a new enlarged drill bit and mechanical plugging, which could solve the hole gush problem. Experiments were made to measure the expansive pressure of the SCA working in boreholes of F40 mm and F100 mm. The difference between two sizes of cracking phenomenon was compared and analyzed to show that large scale borehole soundless cracking has larger expansion pressure and faster reaction speed than traditional soundless cracking. Based on the experimental data, finite element analysis was utilized to study the stress concentration and stress distribution between two neighboring large boreholes in several media during the cracking process. Using the data from experiments with finite element numerical simulation, the brittle material fracture condition was analyzed to design the parameters of the borehole mesh. With the theoretical analysis, the technological process and reference parameters of large scale borehole soundless cracking were proposed, including the borehole spacing, burden distance, depth of the borehole and so on. Then a single rock was cracked with the new enlarged drill bit and new plugging, and the results proved the feasibility of the new large scale borehole soundless cracking technology, which achieved the expected goal of improving the cracking ability and reducing the cracking time. This paper presents a new efficient rock cracking method for blasting sensitive areas, and which could apply to mining engineering, demolition engineering, excavation engineering and other engineering applications where there is a demand soundless and non-vibration fracturing of rock.

Aug 1, 2013

By D. C. Fraser

"Geophysical Engineering and Surveys Limited of the Keevil Mining Group have routinely conducted ground surveys with VLF-EM receivers for the past two years. Both Crone's Radem and Ronka's EM16 have been used.VLF-EM dip-angle data often yield complex patterns which require considerable study for a proper interpretation. A method was developed which allows field operators to transform the noncontourable dip angles into contourable data, producing conductor patterns which are immediately apparent to exploration personnel untrained in VLF-EM interpretation.VLF-EM contoured data generally peak very close to the top of a conductor, thereby allowing drill holes to be spotted accurately. However, the data generally should not be used alone to select drill targets because structures may be sufficiently conductive to yield strong anomalies. Thus, magnetic and/or vertical-loop EM correlations may be considered as necessary criteria for drilling.VLF-EM surveys can replace IP surveys in certain environments. For example, the Restigouche orebody in the Bathurst camp of New Brunswick yielded a VLF-EM anomaly as distinct as that obtained by IP, although the body did not respond to vertical-or horizontal-loop EM. However, the cupriferous breccia pipes of the Triba mine near Batchawana, Ontario yield strong IP anomalies but not VLF-EM anomalies, illustrating that disseminated ore targets should be sought with IP rather than with VLF-EM."

Jan 1, 1971

By B. F. Giyani, D. Rahal

"Stirred media mills have proved to be more energy-efficient than the conventional ball milling for fine grinding applications. The mill performance is governed by a number of operating variables including mill stirrer speed, feed particle size, solids content and slurry rheology. A study was conducted to assess effects of mill speed, media size and density, and slurry density on the Stress Intensity (SI) in a VXPmill and thereby the relationship to mill performance. For the mill speeds tested, it was found that the optimum tip speed is 7 m/s. If the speed is too high (12 m/s) energy losses result due to mechanical friction losses and heat generation. If the speed is too low (3 m/s), the kinetic energy is not sufficient to promote breakage. The size reduction ratio increases with the increase in mill speed and the decrease in solids content especially in the coarse fraction particle sizes. The effect of slurry rheology on mill performance was shown by assessing the effects of increasing solids concentration and decreasing particle size. Rheological effects seemed to interact with mill speed such that the mill was less energy-efficient at higher solids content and at higher mill speeds particularly for grinding to fine particle sizes. There is an opti"

Jan 1, 2017

By Denni Nikols

"Planning for coal beneficiation in the electric utility industry is relatively complex, involving the coordination of experts and specialists in a broad range of fields, as well as compliance with a wide variety of government regulations.This paper examines the role of the planner, reviews possible benefits of coal beneficiation, identifies potential problems and illustrates a typical planning schedule.The steps involved in the planning process are:Step I-Bench- and pilot- washability studyStep 2- Wash plant designStep 3- Power plant and boiler designStep 4-Mine designStep 5-Major environmental and technical problems to address.IntroductionElectrical utilities and coal have a long and intimate relationship . Cleaned coal is becoming an increasingly popular fuel with the utilities for a variety of reasons. Generally, the greatest impetus to burn a cleaned or prepared coal fuel comes from the need to control airborne pollutants.Long-range planning is a standard practice for electric utilities, forecasts of demand must be made well into the future. Since the lead time required to provide new facilities is often as long as 10 years and the cost very high , planning becomes an important task.For a utility that owns and directs the operation of its coal mines, the mine planning or fuel acquisition planning takes on the magnitude of other corporate planning functions. It is from this perspective that a utility would view coal preparation. Except for the interaction of a coal-fi red plant on the actual mine design the planning considerations o f a beneficiating facility for a captive mine or a contract raw coal supply are about the same. Because TransAlta Utilities is currently supplied from captive mines, this discussion will tend to focus in that direction.It is the role of a planner to plan. This is easy to say but it is not always easy to do. Often we are working within a context that resembles the geological time scale. Frequently the objectives are not clearly defined when we begin and ultimately our plans are tested in the waters of government regulations and cost benefit analyses .Planning for beneficiation of Plains coal, or any coal, provides just such a test. The planner's role in this endeavour requires a wide vision. While parts of the process may be amenable to classical methods of project scheduling, the broad range of subjects and interaction of seemingly unrelated tasks is sure to obscure some of the considerations that must be made. Therefore, the planner's chief role is coordinating the work of many experts and specialists toward the final objective.Among the specialists are combustion , geo technical, mining, civil , and mineral processing engineers , geologists, hydrogeologists, soil, and reclamation experts to list a few.When one considers coal beneficiation, the planning part o f that consideration is probably more complex than any other single engineering function. Due to the company's location in the Alberta Plains and the proximity o f the mine to the thermal generating station, this paper will tend to emphasize that situation.Beneficiation may offer some advantages over run-of-mine coal to the power plant opeator. Some of these advantages are: removal of a contaminant, power plant efficiency gains , lower plant capital costs (for new plants), possible lower mining costs."

Jan 1, 1984

By A. Warczok, T. A. Utigard

"Slags from smelting of copper concentrates contains from 1 to 15% of copper. Copper is present in the form of copper or copper matte inclusions of size from 2 to 1000 micro, and as dissolved cuprous oxide. Removal of the copper requires the slag reduction, primarily reduction of magnetite and co-reduction of cuprous oxide. Thus, the kinetics of the slag reduction play an important role in copper recovery. Instantaneously, at the contact of carbon and a slag the gaseous film is formed. The magnetite and cuprous oxide reduction is going through a gaseous film, separating the slag and carbon of a coke or electrodes. The thickness of a gaseous film grows to a critical value and gas bubbles, containing CO and CO2, are created and rise up in the slag. Results of measurements of kinetic of the slag reduction with graphite showed high value of activation energy, close to the value of activation energy of Boudouard reaction. Strong temperature dependence of the reaction rate points out the thermal instability of the reacting system. It was found that the slowest process in the reduction stages determines the loop of CO and CO2 transfer and magnetite diffusion to the slag/gas film boundary. Strongly endothermic Boudouard reaction seems to cause thermal instability on the reaction surface. So, heat transfer to the reaction surface is very important. Due to low thermal conductivity of a slag the convection dominates in the heat transfer. So, any slag stirring accelerates the rate of reduction and coalescence of metallic copper or copper matte inclusions."

Jan 1, 2015

By Rajiv Kalra

This paper reviews the following aspects of the world?s largest manufactured Grinding Mill?s in terms of diameter and power, along with the world?s biggest shop assembly and trial run of the mills delivered to Sino Iron Magnetite Project in Australia. 1. An overview of the basic flow sheet of the Sino Iron (Magnetite) Project located in Australia 2. An overview of in-house designed CITIC Heavy Industries 12.2 m (40ft) F x 11 m(36ft) LG ? 28MW AG mills including FEA and major components 3. In-house manufacturing at CITIC-HIC work in Luoyang China of all major components for 6 off Ø12.2 m(40ft) AG mills and 6 off Ø7.9 m(26ft) x 13.6 m(44.6ft) LG-2 x 7.8 MW Ball Mills 4. Major aspects of design and preparation of the biggest shop trial run of Ø7.9 m(26ft) x 13.6 m(44.6ft) LG Ball Mill witnessed by international EPCM?s and clients in July 2009. 5. Major aspects of one piece assembly of 1300 tonne rotating element of the Ø12.2 m(40ft) x 11 m(36ft) LG AG Mill and Ø7.9 m F (26) x 13.6 m(44.6ft) LG Ball Mill at the port of the export China and transport to Australian Port and then to site. 6. An insight to unique installation methods used for Ø12.2 m(40ft) and Ø7.9 m(26ft) rotating element lifting on the mill foundation in one piece assemblies. 7. CITIC Heavy Industries present capability for in house design and manufacture of Grinding Mills up to Ø13.7 m (45 ft) with 35 MW Gearless drives and Ø12.2 m(40ft) with 2 x 10 MW Geared Mill drives

Jan 1, 2012

By E. Godin, M. Rigaud, S. C. Panigrahy, I. Malinsky

"RésuméDes boulettes de concentres d'hématite spéculaire à basse silice ont été produites en substituant la bentonite par de la tourbe, adéquatement traitée, additionnée d'une faible quantile de soude caustique durant le boulettage. La réductibilité de telles boulettes et leur gonflement pendant la réduction ont été évacues, en utilisant quatre mélanges gazeux différents, formes de H2 - CO - N2.L'influence du pouvoir réducteur du gaz utilise, sur le gonflement des boulettes, à été mis en évidence. Quelles que soient ces conditions réductrices, les propriétés mesurées sur les boulettes liées a la tourbe sont comparables aux propriétés obtenues avec des boulettes traditionnelles liées à la bentonite.ABSTRACTAdditions of peat moss and small quantities of NaOH during balling of low silica specular hematite concentrates have eliminated the need to use bentonite as a binder. The reducibility and swelling of such pellets have been evaluated using four different gas mixtures, consisting of H2 - CO -N2. The influence of the reducing power of the gases, on the swelling behaviour of pellets has been documented. Under the different reducing conditions, this new type of pellets exhibit properties similar to the ones obtained using bentonite."

Jan 1, 1987

By H. A. Hamza

An experimental study of the settling characteristics of a washery effluent originating as tailings from a froth flotation circuit was undertaken by using a systematic approach to select the most appropriate flocculant(s) under predetermined conditions. Selection and evaluation procedures which greatly reduce the effort required to select flocculants are described. The results show that, although different flocculants display superiority at different ranges of dosage. Separan MG 700 (Dow) is the most suitable on absolute economic grounds. Flocculant evaluation is based on a Cost Performance Index (CPI) which expresses the cost of flocculant (¢/ton) required to produce a unit settling rate (in./hr). From experiments carried out with a number of flocculant aid and flocculant combinations, it was concluded that the use of flocculant aids can be economically justified only if the settling rates required are higher than those obtainable at the optimum flocculant dosage. Otherwise, the value of the flocculant aid appears to be limited largely to the reduction of supernatant turbidity.

Jan 1, 1979

By N. Schmalbein, L. von Ketelhodt, L. Kotelo

"The mining industry continues to remain challenged. Lower commodity prices, increasing labor costs and more importantly diminishing reserves are amongst some of the primary factors contributing to the difficulties faced. Ore sorting technologies have demonstrated their potential to improve the downstream beneficiation performance. The general processing route sees all primary crushed material milled for liberation and then processed in accordance with characteristics of the gold therein, i.e.: refractory golds would require direct leaching or oxidation whilst free gold would follow the conventional cyanidation process, after gravity concentration. Ore dilution increases the associated operating costs within each stage of this process. The opportunity to process the same throughput at a higher grade can only be achieved through pre-concentration. Sensor based sorting has been examined on numerous occasions by various gold producers. Test work carried out on different bulk low grade gold ores has shown the successful applicability of ore sorting to remove waste, whilst maintaining high recovery rates of gold. The results of a combined XRT/Laser sensor sorter have shown grade improvements of over 300% from feed grades of 0,25g/t to 1,15g/t at gold recoveries of 66% and waste ejection rates of 85%. This paper presents some of the results from the work undertaken by STEINERT with respect to gold sulphide ore sorting and presents a modelled financial scenario, which can enable a company to target and reclaim low grade ores.INTRODUCTION The mining and minerals processing industry presents with many different challenges including, volatile commodity prices, increasing labor costs and more importantly diminishing reserves. Conventional processing routes will continue to play a crucial role in the beneficiation process, however innovative methods of reducing operating costs and optimizing on the overall circuit performance is where technologies such as sensor based sorting come into the fore. Sensor based sorting as a dry mechanical process not only reduces water consumption by eliminating unnecessary waste but also reduces the requirements for reagents in the downstream processes. Sensor based sorting under dry conditions presents a highly efficient alternative to wet pre-concentration methods such as dense medium separation (DMS)."

Jan 1, 2017

By Hyung Sup Choi

The preparation of high-purity zirconyl compounds was studied in order to develop an economical process for obtaining pure zirconium via the caustic fritting of zircon sand. The direct dissolution of caustic frits with concentrated hydrochloric or nitric acid at 80c. followed by the addition of a small amount of acidified gelatin, gave high-purity zirconyl chloride or nitrate. The addition of a small amount of gelatin caused a mutual flocculation between colloidal silica and gelatin. The precipitation of this silica floc markedly lowered the content of silica in the product. The silica content of the compounds (or solution) so produced, generally less than 100 ppm., was sufficiently low for tributyl phosphate extraction for nitrate solutions. It was found that the degree of purification de-pends not only on the procedures employed but also on the nature of the frit itself. Silica was more effectively eliminated from the fritted product produced at higher temperatures, and less silica was present in the com-pound prepared from the frit produced in a shorter heating time. In order to ascertain the nature of the

Jan 1, 1965

By Andre Vien, D. H. Hendriks, D. Willet, B. C. Flintoff

"For many years the training of mill operators was an informal process which involved senior operators training junior operators on an as-needed basis. Recognizing the needs and benefits of better training some companies, and even some provinces through legislation, have moved to ensure that a formalized training program exists in the plants. These programs tend to focus on basic safety and operations. Much remains to be done. With the more rapid incorporation of new processing and information technologies, and the goal to keep labour costs to a minimum by doing more with less, operator training has become a critical issue. This paper briefly examines the evolution of training programs, provides some measure of their effectiveness, and explores some recent developments which could have a very significant impact on the industry.PreambleOne can draw an analogy between operator training and the mechanical support of production equipment. When we buy a piece of process equipment it is critical that the mechanical installation be done properly to ensure that the device will operate at peak performance on start-up. Once the equipment is running, some form of preventive maintenance is required to ensure continued efficient operation. The operators and the equipment are both elements of the processing system, yet the former do not seem to get the same ""start-up"" or ""operating"" support. Are they not seen as critical to efficient operation? Why is this so? What impact does it have? How can we improve?These are all very logical and important questions, although the answers are not nearly so obvious. In the mineral processing industry, progress in operator training over the past thirty years has been limited and quite variable. To address the perceived need for a more coherent and consistent approach, some provinces have moved to incorporate basic training requirements in their legislation. Some plants have gone a few steps further by building integrated training programs into their operating culture. One conclusion which can be easily reached is that there are no standards, and that the range of training activity is great. In other words, a flotation operator is not a flotation operator is not a flotation operator. Their knowledge and skills are very much a function of training and experience, which are clearly corporate and site specific."

Jan 1, 1994

By S. M. J. Mirazimi, F. Rashchi

Recovery of vanadium from LD (Linz-Donawits) converter slag was evaluated by means of microbial leaching. Vanadium leaching was performed in two stages. In the first stage, the bacteria were grown in a culture medium and in the second stage; vanadium containing slag was added to the metabolites produced by bacteria. Bioleaching was performed using heterotrophic bacteria Pseudomonas Putída. Control tests without bacteria inoculation were also performed and the results were compared with bioleaching outcomes. Optimal conditions for the bioleaching of vanadium containing slag were determined.

Jan 1, 2011

By B. A. Kjarsgaard, C. J. Mwenifumbo

"Abstract - Natural gamma-ray measurements were made in the GSC Smeaton drillhole as part of the borehole geophysical classification of kimberlite pipe 169. In addition, forty samples of Cretaceous sediments (shales, siltstones, and sandstones) and thirty-five kimberlite samples, selected from the drill core, were analyzed for major and trace elements. These elements included potassium (K), uranium (U), and thorium (Th), which are the main naturally-occurring radioactive elements.Different phases of the kimberlite, and the Cretaceous sediments which show variations in the gamma-ray activity, can be easily delineated on the gamma-ray logs. The gamma-ray logs indicate that the radioactivity in the kimberlite derives mainly from Th, and, to a lesser extent, U. Most of the kimberlite units are enriched in Th and U relative to the Cretaceous sediments, and these radioelements are mainly hosted by accessory apatite and perovskite, and minor zircon. Potassium concentrations are low in the kimberlite. The higher K concentration in the sediments clearly distinguishes the Cretaceous sediments from the kimberlite.The U/K and Th/K ratios show important and distinct differences between the two major types of volcaniclastic kimberlite. Kimberlite lapillistones have higher U/K and Th/K ratios than the olivine crystal tuffs. Furthermore, standardized U/K and Th/K geophysical logs can be used to separate marine reworked olivine shoreface sands from other shallow marine sediments that contain kimberlitic detritus. The identification of different phases and/or stratigraphic facies of kimberlite on the basis of radioelement distributions means that gamma-ray spectrometry can assist exploration, particularly in regard to diamond grade distribution."

Jan 1, 1999

By Cheryl Devine, Radhakrishnan Mahadevan, Vladimiros G. Papangelakis, Srinath Garg

The microbial-mediated recovery of valuable metals locked in mining wastes presents an economical alternative to conventional hydrometallurgical processes. The present study investigated the bioleaching response of a low-grade nickeliferous pyrrhotite tailings (0.6 wt% Ni) and an upgraded pyrrhotite tailings (1 wt% Ni) produced by Vale Base Metals in the Sudbury Basin of Ontario, with the ultimate aim of maximizing Ni recovery. The initial part of the study focused on the bacterial adaptive evolution protocol, by repeatedly sub-culturing an indigenous culture from an acid mine drainage site on 2% (w/v) pyrrhotite tailings. The results showed that the extent of Ni dissolution is positively correlated with microbial activity. Microbial profiling revealed A. ferroxidans to be the dominant member of the microbial consortium. The enriched culture was used for optimizing the growth medium by varying the concentration of essential growth nutrients. Finally, an aerated biotic and abiotic leach of a 10% (w/v) upgraded pyrrhotite tailings with and without pH control, showed a higher recovery of Ni in the pH controlled experiments. These results demonstrate that a high concentration of the oxidant Fe3+ in solution promotes the dissolution of Ni. Furthermore, the sulphide conversion into So was found to be higher in the pH controlled experiments (32%), relative to the experiment without pH control (10%).

Jan 1, 2015

By Loui Geoffroy, Philippe Gaultier, Martin Piotte, Claude Coache, André Drouin

"Automatic driving at high speed of an underground truck was tested at Brunswick mine in September 1995. Modifications to the truck included: a remote interface to control actuators, front and back video cameras to follow a roof mounted optical guide and proportional hydraulic controls on the steering.The mathematical model of the hydraulic system was adjusted using least square regression. The steering data, used in calculating the regression parameters, were acquired from the moving truck. The automatic steering control used three measured variables: lateral deviation, angular deviation and steering angle. Lateral deviations are obtained using the cameras, which are in continuous view of the guide, while steering angles are acquired from an extensiometer placed at the articulation point of the vehicle. Gain scheduling was used to compensate for vehicle speed and available hydraulic flow. Non-linear characteristics of the modeled hydraulic system were offset using open loop compensation.Speeds up to 23 km/h in forward direction and 13 km/h in reverse were achieved deviaduring continuous testing along one of the mine’s production drifts. Proportional steering was essential in achieving high speeds, as it enabled more precise positioning of the vehicle’s steering direction while reducing the abuses on cylinder and cylinder pins via diminished oscillations about the optical guide at high speeds."

Jan 1, 1997

By A. Bhowmik

Uranium Refining is the process in which undesirable neutron absorbing elements such as Boron (B), Gadolinium (Gd), Cadmium (Cd), Europium (Eu), Samarium (Sm) and other heavy metals (Fe, Ni, Co, Ca, Mg etc.) are removed to make it nuclear pure. At present, Uranium refining is carried out by solvent extraction process by using organic based solvent e, g. TBP diluted with Kerosene. The above process generates lot of nitrate bearing liquid waste and degraded organic. In order to eliminate use of hazardous organic and ammonia for Uranium refining altogether, a new process has been developed. In the new process, Yellow Cake is dissolved in nitric acid and uranium peroxide hydrate is precipitated selectively from the solution leaving all the impurities in the solution by using commercial grade hydrogen peroxide at a pre-defined pH, U conc., temperature and stoichiometric quantity of hydrogen peroxide under mild agitation. The precipitate is filtered and washed with DM water to obtain nuclear pure product meeting purity standard as per ASTM C ? 753-99.The product is spray dried and calcined to obtain uranium oxide. The process eliminates use of organic, flammable, toxic chemicals, consumes less quantity of nitric acid and uses environfriendly chemical hydrogen peroxide. The process is simple and can be integrated in the mill. A patent application is entering national phase in several countries including CANADA and abstract/full paper is available in WIPO publication no: WO/2009/013759.

Aug 1, 2010

By R. D. Brown

"Finance Minister Donald Macdonald's budget of May 25, 1976 featured a restructuring of the anti-inflation profit controls and a grab bag of tax changes, some of direct interest to the mining industry. All Canadian taxpayers now will be permitted to write off immediately 100% of mineral and oil and gas exploration expenses included after• May 25, 1976 and before July 1 1979. The cost of acquitting Canadian resource property after May 6, 197.4 from a federal or provincial government will now clearly be included in Canadian development expense, and provincial drilling and exploration incentives received after May 25, 1976 will not reduce exploration and development expense for federal income tax purposes. Under tough new anti-inflation profit controls, all controlled businesses, except distributions, will essentially have one uniform set of rules for• determining allowable profit margins; this allowable margin will be determined by product line or by over-all net margin and will be 85% of the higher of the margin obtained in the five years preceding October• 13, 1975 or the one year preceding May 1, 1976. The basic capital cost allowance system is to continue, but many rates will be revised. The ability to offset losses created through claiming capital cost allowances on leased equipment, etc. against other income will be ended with respect to transactions entered into a/te1• budget night. Miscellaneous other tax changes will raise the low rate base for Canadian-controlled private corporations to $750,000 increase retitement plan contribution limits and reduce the rate of branch tax imposed on branches of corporations resident in a country with which Canada has a comprehensive tax treaty to equal the withholding tax rate on dividends under that treaty."

Jan 1, 1976

By J. N. De La Vergne, J. S. Redpath

"The authors make recommendations that they believe will improve the efficiency of a mining company's use of a mining contractor's services. The recommendations are in the form of specific ""DO"" or ""DO NOT"" instructions, giving explanations and covering the contracting process from the end of the feasibility study to the end of the job. IntroductionThis paper is an attempt by the authors to set out some of the things which they feel an owner should consider to achieve maximum effectiveness from mining contractors. It is based on our experience as contractors as well as our experience as consultants to owners. Should this paper create the impression that we feel all the responsibility lies with the owner, this is neither our intention nor our belief.Before the Tendering Process BeginsUse Defined EstimatesIn Feasibility Study DO NOT estimate your cost or schedule by telephoning contractors and asking them for ballpark figures. The only kind of estimate that is worth anything is the one that is clearly defined on paper and bears the signature of the author. This type of time or cost estimate takes time to prepare. In general, the estimate will be worth what you pay for it.Ensure Adequate FinancingDO NOT ask contractors to tender on a project unless the funds have been approved for it. Remember that, depending on the size of the job, it will cost the contractor from $5,000 to $50,000 to prepare his tender. When financing is not assured, a single contractor should be approached regarding a detailed estimate and he should be paid for it. Contractors should not be expected to finance speculative mining ventures."

Jan 1, 1980