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By George Kellock

Introductory The Alberta Provincial Government has contemplated a revision of the Mines Act for some time past, and it is understood that a definite decision has now been made to do this at the next session of the Legislature. The Operators' and Miners' organizations of the Province have been asked, or at least have been given the opportunity, to submit their views and ideas relative to the proposed changes. The operators have already drafted out a number of changes which they feel would improve the Act from the standpoint of safety and practicability, and this paper has been prepared so that the general membership of the Rocky Mountain Branch of the Institute, which is composed largely of the operating and certificated officials of the mines, might have an opportunity to discuss, criticize, and improve upon the suggested changes which the operators are putting forward.

Jan 1, 1929

By A. R. Farkoosh, J-P. Fortin, M. Pekguleryuz, S. Bagherpour

"Titanium aluminides are structural intermetallics which offer an attractive combination of high temperature strength and light weight. For such properties, these intermetallic alloys have become front-runners in replacing nickel-based superalloys used for several high temperature applications. These alloys are produced from metallic titanium, aluminum and master alloys involving an expensive and difficult process. A low cost alternative to current industrial production method is the new modified aluminothermic process which directly reduces titanium oxide (TiO2) to titanium aluminides. Nevertheless, this process has itself significant challenges in achieving alloys free of oxide inclusions; the close densities of the slag and the titanium aluminides makes slag/molten metal separation a challenging task. Usually, the alloy produced requires a second refining step. In this study, thermodynamic calculations based on CALPHAD method were performed to determine the solidification path and an attempt has been made to develop a criterion to increase the density deference between the slag and the alloy by alloying with appropriate elements. Furthermore, scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques were utilized to examine the microstructure and phase selection of three Ti-Al alloys produced by the aluminothermic reaction, including the as-cast, refined in a controlled atmosphere and inert-gas-refined alloys. The composition range of the alloys studied was restricted to the a2-Ti3Al + ?-TiAl phase field (Ti-30Al) in the binary Ti-Al phase diagram leading to a lamellar structure with different complex intermetallics as shown in Figure 1.INTRODUCTIONTiAl based alloys are promising structural materials for high temperature aerospace and automotive applications. This is due to some attractive properties such as low density, high specific strength, high specific stiffness and high temperature strength retention (Wen-bin, Xue-wen, Hong-fei, & Yong-feng, 2011). These alloys have become leading candidates to replace Ni-based super alloys in gas turbine engines. Replacement of Ni-based super alloy parts with titanium aluminides is expected to reduce the structural weight of high performance gas turbine engines by as much as 20–30% (Kothari, Radhakrishnan, Sudarshan, & Wereley, 2012)."

Jan 1, 2016

By Sabry A. Sabour

Metal price is among the key variables in the open pit optimization and the economic evaluation process. The common approach to handle metal prices in open pit mine planning is to optimize the ultimate pit and the mining schedules using a fixed, flat metal price. In this respect, metal price is assumed to be known with certainty throughout the entire mine life, which in some cases can reach 80 years. Given the volatile nature of metal markets and the metal price cycles, the conventional pit optimization approach may generate sub-optimized mining plans, which results in either extra costs to mining projects or lost revenues, or both. Long-term operational decisions such as future pit expansions, beyond the currently optimized limits, cannot be handled using the pit optimization approach based on flat metal prices. There is a growing interest in the mining industry to model and manage such market uncertainty in the pit optimization as well as the project evaluations in order to maximize the value of mining operations. In this paper, the author will outline a practical approach to optimize the ultimate pit taking into account the volatility and variability of metal markets. The proposed approach uses a combination of the pit optimizer of the commercial MineSight package and a simulation-based economic modeling real options valuation approach employing the least-squares Monte Carlo algorithm. MineSight pit optimizer employs both the floating cone for initial optimization exercise and the standard Lerchs-Grossmann algorithm. In this paper, Lerchs-Grossmann option will be used to generate the pit shells. Real options valuation approach used in this study is based on generating multiple metal price scenarios. Metal price uncertainty is modeled using stochastic metal price models such as the geometric Brownian motion and the mean-reverting process. The mining operational scenarios corresponding to the simulated metal prices are then optimized using the least-square Monte Carlo approach. The objective is to maximize the discounted cash flow value of the project while incorporating the operating flexibility to revise the operating status of the open pit with time as new information becomes available. The focus of this work is on the practicality of the proposed uncertainty-based pit optimization approach and the difference it can make to the technical operational mining decisions. A case study of a hypothetical open pit poly-metallic mine is provided. The deposit contains copper, gold and silver grades. The run of mine ore is sent to the process plant that produces copper concentrate with copper as the main metal and gold and silver as the by-products. Four uncertain variables are considered here include copper, gold, silver prices and foreign exchange rate. Both copper price and exchange rate are modeled using the mean-reverting process while gold and silver prices are modeled using the geometric Brownian motion. The case study is performed using both the conventional flat price pit optimization approach and the proposed uncertainty-based one to compare results.

Aug 1, 2013

By E. Thune, F. Stålesen, E. O. Stensholt, O. M. Dotterud, E. E. Henriksen, P. O. Ramsdal

"The development and commercial operation of the Falconbridge chlorine leach process have been described in papers in 1985 and 1987. Since this time, various process improvements have been implemented and the capacity of the Kristiansand refinery has been increased to 85 000 t/y Ni, 40 0000 t/y Cu and 4500 t/y Co. The focus has been on continuous improvements in productivity, the use of energy and other costs. Several environmental issues have also been eliminated or reduced since 1987. IntroductionThe first nickel refining operation in Kristiansand, Norway, started in 1910 based upon raw materials from Norwegian mines. In 1929, Falconbridge Nickel mines purchased the refinery to acquire information and the patent rights to the Hybinette refining process that was practised at the small Kristiansand refinery. Falconbridge ownership has now, for more than 70 years, provided a strong base regarding raw material supply, financial resources and technical support for further expansions and major technical improvements at the refinery.The main concepts of the new chlorine leach process were developed in the laboratories from 1966 to 1969 and the process was piloted from 1970 to 1972. The main stages in the commercial plant were started in the 1975 to 1981 period. After 1981, there have been a number of process modifications, plant expansions and improvements to operating practices. The developments up to 1988 have been described in previous publications (Stensholt et al., 1986, 1988).This paper presents an overview of the process and how it is practised at Falconbridge Nikkelverk AS (FNA) today and describes some of the main changes that have been implemented since 1988. During this time, the nickel capacity has been expanded from 54 000 t/y to 85 000 t/y and the cobalt capacity from 2000 t/y to 4500 t/y. The paper describes how these expansions were achieved together with continuous improvements in operating efficiency and also gives an overview of the main environmental concerns at the refinery."

Jan 1, 2001

By D. Gaboury

Most hydrothermal gold deposits contain quartz with fluid inclusions that record composition and temperature of the mineralizing event. Quartz has strong chemical and mechanical resistances to weathering and abrasion. Hence, quartz fragments occurring on weathered surfaces or in till cover have the potential to be used for gold exploration as far as we know what is the signification of the volatile content of the fluid inclusions for gold mineralization. In this perspective, fluid inclusions were analyzed in pure quartz by solid-probe mass spectrometry from gold deposits hosted in the Archean Abitibi (Canada) and Paleoproterozoic Birimian (Western Africa) belts. This approach provides the relative abundance of volatiles from families of fluid inclusions decrepitating at specific temperatures (Td). Fluids in gold deposits are aqueous-dominated with CO2 and minor H2S in accordance with their fundamental role as gold-ligands (H2S) and for pH-buffering (CO2) of the gold-bisulfide solubility. However, there is no correlation between CO2 and H2S contents of fluid inclusions with the gold grade of the samples. This suggests that trapped fluids represent a marginal portion of the fluid history recorded by the veins. However, in barren quartz veins away from known mineralization CO2 or H2S are commonly absent. Wide ranges in H2O Td from 250 to 450°C and CO2-H2O Td offsets are common, indicating phase separation. The content of other volatiles seems to be more dependent on the geological setting. Helium content may suggest proximity to a crustal-rooted fault, a critical parameter for gold mineralization. Methane and especially C2H6 appear to be indicative of fluid buffering by organic-rich material such as graphitic-shale. These rocks may provide an important primary gold reservoir from sedimentary metal-rich pyrite. Nitrogen-bearing fluids may be related to a magmatic component but can also be derived from organic-rich sedimentary rocks. For gold exploration, quartz containing CO2- H2S-bearing fluid inclusions and having H2O-CO2-Td offsets within 250 - 450°C has strong vectoring potential.

Jan 1, 2011

By L. Chunpongtong

The Athabasca oil sands mineable resource is located in northeastern Alberta, Canada. In oil sands mining, the ore zone is regulated to have a minimum mining thickness of 3 m and a cutoff grade of 7 wt.%. The current algorithm that is widely used to flag ore zones and waste zones tends to overestimate oil reserves and causes low-grade ore to be processed. This paper presents the development of a more complex algorithm that is more representative of the actual oil found during operations and that can prevent low-grade ore from being sent for processing.

Jan 1, 2014

By C. Jewell, G. H. Rupay

"67 - 2:15-3:00Regeneration of Hydrochloric Acid from Waste Pickle Liquor Using a Fluidized Bed Reactor System. G. H. RUPAY and C. JEWELL, Dominion Foundries and Steel Ltd., Hamilton, Ont.The disposal of acidic waste liquors from pickling processes has always been a problem for the steel industry. With increased awareness toward environmental control and the problems acidic wastes create, processes utilizing recovery and regeneration of the waste acids are becoming more popular. This paper describes the Keramchemie/Lurgi process for regenerating hydrochloric acid from waste pickle liquor using a fluidized bed reactor system. The process parameters are outlined, together with a brief description of the equipment. This is followed by a discussion of the operating problems and concludes with economic data."

Jan 1, 2000

By Michael McClintock, Bern Klein

"The high pressure grinding roll (HPGR) is a relatively new comminution technology that is gaining popularity for providing energy efficient solution to hard rock mining operations. A significant barrier to increased adoption of HPGRs is the present requirement for large amounts (excess of 2 tonnes) of sample for pilot testing, which may not be possible for most early stage projects. Three methodologies have been developed at NBK Institute of Mining Engineering at the University of British Columbia that may be used for sizing design optimization of HPGR circuits. All three methodologies use a MTS pistonpress to simulate HPGR comminution. These tests are capable of providing information regarding energy consumption, energy breakage relationship, reduction ratio, and product size distributions. In a period of slow economic development, these methodologies are critical to allow the industry to cost effectively understand the operational benefits of HPGR implementation. This paper examines previous test work done at UBC, as well as the development of an HPGR and piston press database for use in sizing and budgeting of HPGR circuits.INTRODUCTIONCurrently, the mining industry faces several challenges due to falling commodity prices and escalating costs. This has applied pressure for operations and projects to reduce costs and improve project economics. In addition engineering and metallurgical budgets have shrunk as companies try to conserve cash. Improvements and optimization of milling and comminution circuits is one area project economics may be significantly improved. By considering alternative comminution technologies such as the high pressure grinding roll (HPGR), energy operating costs may be greatly lowered. Many have begun to implement HPGR crushing as an alternative to semi-autogenous grinding (SAG) mills, including KGHM and, Sierra Gorda, and Freeport Mc-MoRan’s Cerro Verde operation. However, implementing new technology for companies with little or no HPGR experience may not be practical. An operator must consider both feasibility and economics of a circuit. Currently, consideration of the HPGR requires expensive pilot scale testing for which large sample sizes are needed. In addition, few laboratories are equipped for running pilot scale HPGR test programs. Furthermore, the results of pilot HPGR testing are dependent on the quality of the sample, which cannot represent variations across a deposit. In contrast, ball mills and SAG mills can be sized using the Bond Mill Work Indexes that require a small amount of sample which enable a number of different geological blocks to be tested to allow engineers to have a complete understanding of how the comminution circuit will perform for the life of mine."

Jan 1, 2016

By M. S. Diederichs, G. Walton

"Developments in understanding the brittle fracture of rock over the past two decades ultimately led to the acceptance of a cohesion-weakening-friction-strengthening model as an appropriate strategy for the modelling of spalling using a continuum approach. This strength model has been used to replicate observed failure depths and geometries for a number of case studies in the literature, most notably the AECL Underground Research Laboratory in Manitoba. One thing which these case studies typically ignore, however, is the influence of rock dilatancy on the evolution of brittle failure. Physically, this phenomenon is the volumetric expansion of the rock due to fracture opening; numerically, this phenomenon is captured by the flow rule, which is often characterized by the dilation angle, ?. Accurately modelling rock dilatancy in conjunction with strength evolution is necessary both to predict the magnitude and distribution of ground displacements, as well as the exact depth and shape of the fracturing zone. Both of these factors can have significant implications for support design. This paper is focussed on presenting some of the recent developments in this field in the context of a number of numerical modelling case studies. Initially, a new model for the dilatancy of brittle rock is presented, as well as some representative data and model parameters for different rock types. Next, several case studies of highly stressed tunnels and shafts are presented. The results of continuum numerical models are presented to demonstrate the ability of the back analyses to match observed in-situ measurements and obtained. The predictive capabilities of the material model are also highlighted for cases where sufficient “a priori” information (such as laboratory compression testing data) are available. The issues of model nonuniqueness and strain-localization/bifurcation are also addressed."

Jan 1, 2015

By F. Sorenson, P. A. Castellarini, F. Garbarino, M. N. Garcia

"Recently, significant efforts to improve productivity from the tight intervals of the Mulichinco Formation within the Sierra Chata Field in the Neuquén Basin have been ongoing. Because conventional high quality reservoirs were being developed in this field, a proper reservoir understanding and completion approach was applied. After developing these high permeability reservoirs, the operator began evaluating the tight intervals and new areas within the field, but a completely different approach was necessary to achieve motivating production improvement.An extensive study to help enhance reservoir understanding and identify key factors controlling productivity of these tight intervals (which tend to be in the range of 5 µD) has been ongoing. Some of the issues discussed in this study are 1) petrophysical review, 2) rock properties calibration, 3) geomechanics understanding, 4) faulting and micro faulting/lineaments description, 5) stimulation and completions review and, 6) understanding key production drivers.As in many other tight reservoir projects, a considerable area of the reservoir must be effectively stimulated during the hydraulic fracturing process to achieve economic productivity. Two critical issues hinder these objectives. First, the low permeability in addition to a pore pressure close to or even lower than hydrostatic are critical characteristics when attempting to flow back the well and clean up fractures. Second, very high horizontal stress anisotropy resulting from a strike slip stress regime promotes the generation of simple planar bi-wing fractures. It is well-known that this fracture geometry will contact much less reservoir area compared to more complex fractures, as the operator would normally intend to create at very low permeability reservoirs.This paper discusses these issues and how they were addressed. A pilot drilling and completion program was initiated during 2012 to validate this study. Key factors include well location relative to formation unconformities, their orientation relative to the far field principal stresses, hydraulic fractures generated, and overall completion design."

Jan 1, 2015

By D. Verhulst

The Altair process digests ilmenite concentrate in high-chloride HC1 solution, with complete dissolution of titanium and iron. The Fe(III) ions are reduced to the ferrous form, and the solution is cooled to produce crystalline ferrous chloride. Titanium is transferred by solvent extraction into a purified, concentrated Ti stream, which is spray-hydrolyzed to produce TiO2 hydrate. The hydrate is further calcined with additives to generate a high-quality pigment. All the chloride streams are recycled. In the original flowsheet, the iron chloride is pyrohydrolyzed by spray roasting to regenerate 18% HCl, which is subsequently converted to HC1 gas and water by pressure-swing distillation. A modified flowsheet includes an alternative to iron chloride spray roasting, producing more concentrated HCl and decreasing the amount of solution to be distilled. Improvements in digestion, solvent extraction and final pigment production are also introduced. A 100 t/y pilot plant is being built and will test the new concepts and confirm the overall water, acid and impurity balances of the process.

Jan 1, 2006

By T. H. Peters

The historical development of this program, dating from the construction of Nickel Park at Copper Cliff in 1917 to the various current projects carried out in the Ontario Division's program, is reviewed. Practices used to grow vegetation on stressed areas, the beneficial aspect of the improved aesthetic appearance of company properties from the point of view of public relations and the improved approach to the workplace by the employee are discussed. The revegetation of the tailings area and its gradual transformation into a Wildlife Management Area is reviewed.

Jan 1, 1978

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 J. P. Messervey

THE story of the efforts made by the Department of Mines of Nova Scotia in the search for and investigation of mineral resources for the Canadian war effort began in the spring of 1937. During the past five years, however, heavy enlistments in the Active Service Forces by employees of the mining industry of the Province caused a recession in the production of coal, salt, and other essential minerals required to keep industry rolling on a wartime basis. A marked increase was shown during the period in prospecting for 'strategic' minerals, not only by individuals but also by some of the foremost mining companies. The Provincial Government offered encouragement in this field of endeavour by the enactment of legislation whereby the prospector was enabled to secure the maximum area of ground in a prospecting license at a minimum of cost. The labour requirements on the ground staked, however, remained unchanged. The Nova Scotia Department of Mines continued active investigation of minerals vital to the war effort. These included fluorspar, barytes, diatomite, limestone, and coal. Fundamental knowledge concerning the geology and mode of occurrence of these minerals was accumulated and extensive diamond drilling was carried out on the promising occurrences. Work in these fields is being continued.

Jan 1, 1945

By C. H. Stockwell

"The Precambrian rocks of southeastern Manitoba contain a great variety of mineral deposits, including gold, chromium, copper, nickel, lithium, tin, beryllium, tungsten, and molybdenum. Although considerable interest has been shown from time to time in each of these types of deposit, production to date has been almost entirely in gold. This has had a value of about $26,000,000 and has been derived chiefly from the San Antonio mine, with lesser amounts from the Central Manitoba, Gunnar, Beresford Lake, Ogama-Rockland, Diana, and other properties.Most of the deposits lie within volcanic and sedimentary rocks or within basic intrusions cutting these rocks. These favourable rocks occur in several areas, which have been given local names and are separated from one another by large bodies of granite (Fig. 1).In general, the several areas are characterized by different types of mineralization. Thus, the Rice Lake-Beresford Lake area contains numerous gold deposits and has yielded almost all the gold production to date; the Maskwa River, Euclid Lake, and Oiseau River areas are, on the whole, characterized by deposits of chromium, copper, nickel, lithium, tin, and beryllium; and in the West Hawk Lake area there are deposits of gold, tungsten, molybdenum, and lithium.As might be expected in a district containing such a variety of mineral deposits, the structural conditions controlling their deposition also vary greatly. It is, accordingly, convenient to discuss the structural geology and mineral deposits of each of the more important areas separately."

Jan 1, 1954

By A. Romero

"Most underground mines require heating or cooling systems to meet health and safety standards in the working areas. In regions where daily or seasonal fluctuations of environmental conditions exist, these systems tend to be over-sized and operate at low average load factors, which increase both investment and operating costs. One possible approach to reduce the temperature variations of the fresh air supplied to the mine, and so reducing the investment in large heating or cooling systems, is to use rock as a thermal regenerator or thermal storage system. Packed rock beds act as thermal inertial units, damping the atmospheric temperature oscillations to provide a more constant fresh air temperature. However, although regenerators exist in some mines, and packed bed rocks have been studied in detail in solar thermal power applications, there is a lack of tools to design new and sufficiently large storage systems of this kind. This work fills the existing gap by presenting a methodology to design and evaluate the impact on the ventilation systems of these regenerators. The method is validated using existing rock bed systems found in the literature and illustrates possible designs for small and large size regenerators in both hot and cold climates.1 INTRODUCTION “ It is quite amazing how often answers to extremely complicated problems can be obtained in this way, by using greatly simplified models of the real situation for the purpose of calculation.” Whiller, A. in private communication to J. S. Stachulak (1989). Motivation Most underground mines located in regions with extreme climatic conditions require the thermal pre-treatment of the fresh ventilation airflows, whether for heating or cooling. Heating commonly is needed in sites with sub-zero temperatures and is usually effected by direct or indirect burning of natural gas or propane. Alternatively, cooling is required in areas with hot temperatures, or in mines with high underground thermal loads where the fresh air at ambient temperature cannot provide enough refrigeration. Thus, when the ambient air conditions cannot provide by itself enough thermal power to ensure safe underground working conditions, a heating or cooling plant is required, which involves a considerable equipment and operation cost."

Jan 1, 2019

By G. Marchand, R. H. Hay, E. C. Pearson

"AbstractA polishing .technique is described together with two anodic etching methods for aluminum and its alloys. Some of the optical and structural characteristics of the film formed by •these etching methods are discussed and it is shown to what degree these properties of the film are related to the crystallographic orientation of the metallic substrate. Applications to the study of recrystallization and twinning phenomena and to the study of plastic deformation, banding, and texture estimation are discussed. Micrographs are shown .to illustrate the manner in which the technique is particularly well suited to the study of such phenomena.IntroductionThe physical metallurgist is constantly faced with the problem of polishing and etching of metallic sections. Mechanical polishing is tedious, time consuming, and not applicable whenever a surface entirely free from plastic deformation is required. Etchants are generally required to reveal the grain structure in order to determine its size, shape, and regularity, or to bring up constituents. In the case of aluminum, the .most common etchant to reveal grains is a mixture of three acids: HC1, HN03, and HF. This etchant is fairly satisfactory on certain alloys and for certain metallurgical conditions but in general fails to give a good definition of the grain on castings, on highly alloyed products, and whenever the grain is smaller than 100 microns in diameter. Besides size and shape, a grain, or crystal, has an orientation and may be endowed with several types of imperfections."

Jan 1, 1952

By Joseph F. Daniels

In recent considerations of the utilization and beneficiation of coal, the chemise and the chemical engineer have been occupying the centre of the stage with their presentation of the picture of new fuel forms. The stage hands and supernumeraries of the cast, the miners and the consumers who carry the brunt of the present-day burdens, are apt to be forgotten in the glorious settings and the climaxes. With no thought of disparaging or of minimizing the efforts of our fellow scientists, let us remember that economic considerations as well as technical difficulties will limit these chemical applications, which must develop and move slowly before reaching the stage of industrial application at some later day. In the meantime, the coal-mining industry must live on hard faces rather than rosy dreams. In these brief notes it is my purpose to call attention to some of the physical advances in the utilization and beneficiation of coal which have been of interest to the industry in the State of Washington.

Jan 1, 1928

By W. McCombe, G. Remple, L. Nightingale-Mercer

The McClean Lake Mill is located approximately 850 kilometres north of Saskatoon, Saskatchewan, Canada, and is operated by Orano Canada Inc. (Orano). The mill was designed to process high grade uranium ores, and a multi-year expansion was completed in 2014 to increase its production capacity to 24 Mlbs U3O8 per annum. The mill also underwent various upgrades to allow it to safely transition from processing low grade ores to high grade ores from the nearby Cigar Lake Mine. During the metallurgical test work on the Cigar Lake ores, it was identified that some ore zones of the deposit have a propensity to generate hydrogen gas during acid leaching. Hydrogen is a volatile and explosive gas, which poses obvious safety concerns in the leaching circuit. Uranium processing is further complicated by the fact that an oxidant in the form of oxygen gas or hydrogen peroxide is required to regenerate iron in the leach, which further increases the risk posed by hydrogen gas. During 2013 Orano and its consultant Hatch designed and engineered several novel upgrades to the leaching circuit to mitigate the risk of hydrogen gas evolution in the process. Best in class technology was utilized in addition to control and operating strategy changes to ensure the leaching circuit could be safely operated with ores that evolve hydrogen gas. This paper reviews the design concepts and modifications implemented on this unique and challenging project, and also provides an update on the operational reality of hydrogen in the circuit gained through five years of operational experience with hydrogen evolving ores.

Jan 1, 2020

By G. R. Webber, L. M. Azzaria

"The wide interest in the application of the geochemistry of mercury to mineral exploration is leading to the continued development of a variety of analytical methods for the determination of nanogram quantities of this element. The various methods have different degrees of reliability, sophistication and portability. In this investigation, two simple portable instruments were used in geochemical prospecting surveys -an ultra-violet absorption instrument and a similar one modified with gold for the removal of interfering substances. The results show the application of the method to the determination of mercury in soils of different organic content, and in rocks, sulphides and air."

Jan 1, 1969