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By G. Minhas, M. Pule, Y. Laffitte, M. c. McGurn, T. Tzanetakis, Peacey. J., R. Susilo

Titanium (Ti) metal production from titanium tetrachloride (TiCl4) using magnesium (Mg) as a reducing agent is the well-known Kroll process. A chloride route is used to avoid oxidation of the titanium sponge. The sponge is consolidated into ingots and can then be made into powder by melting and atomizing or by hydriding/dehydriding. Attempts at direct powder production have met with difficulties, including low Ti yield and the formation of very fine particles (particles between 25-100 µm are desired). This paper discusses two methods to produce Ti powder in a molten salt medium using magnesium powder as a starting material instead of a pool of molten magnesium. The first method is a direct reduction of gaseous TiCl4 injected in the melt with the magnesium powder in suspension in the molten salt. The second method is a two stage TiCl4 reduction reaction where recycled Ti was used to form titanium dichloride (TiCl2) in the first stage followed by addition of magnesium powder into molten salt in the second stage. A correlation between Ti yield and processing variables such as TiCl4 to Mg ratio, Mg particle size, TiCl2 concentration in the melt, and reaction temperature was studied. The Ti powder formed was also analyzed for particle size distribution. Despite challenges and difficulties encountered, this paper shows some promising results which could provide guidance to others working on direct Ti powder production.

Jan 1, 2015

By A. J. Pearce

MOST mines have a model of some kind to illustrate either geological structure, mining operation, or some special condition or feature of the property. The type used depends on the particular feature or use for which it is intended. At Dome Mines we have developed an interesting and practical application of the horizontal-type model. This model shows the workings of each level horizon plotted on glass. These glass panes are set in frames which, in turn, rest on drawers equipped with rollers which can be pulled out as desired into a light chamber. The features of this model are its rigid steel construction and that any desired number of level plans can be pulled out, eliminating any other interference from other levels. Figures 1 and 2 are photographs of the model cabinet and show its construction and general features. The cabinet is of steel construction with the following overall dimensions: width, 6 ft. 5 in.; depth, 6 ft. 7 in.; height, 5 ft. 2 in. When not in use it can be completely closed-in, making the cabinet practically dustproof. There are 30 drawers, one for each of the 29 levels and one for the surface. The glass in each drawer is divided into two panes, 36 in. by 36 in., of flatdrawn double-diamond 'lustraglass' with about l/32 in. between adjacent edges. The panes are held rigidly in the frames, which are lined with felt strips, and may be adjusted by set screws, four of which on each drawer are shown in Figures 1 and 2. The level workings, on a scale of 1 inch equals 100 feet, are traced in ivory black Windsor & Newtons artist oil paint. Co-ordinate lines are shown in crimson lake, and main geological contacts are shown in their respective colours. Figure 3 is a photograph looking down on one of the levels. The lighting consists of 14 30-watt fluorescent bulbs, with reflectors, under frosted glass. These lamps are much more satisfactory when operated by 60-cycle rather than 25-cycle and, as we had available nearby a source of direct current, this was used. The electrical unit consists of a rotary converter from d.c. to 60-cycle. This arrangement gives perfect lighting, allowing most colours to be easily distinguished. Figure 1 was photographed using this source of light, Figure 2 using an outside floodlight.

Jan 1, 1945

By J. A. Espinosa-Guillen, J. A. Lopez-Molina, S. García, J. A. Valencia-Quintanar

"The design and implementation of grouting treatments in rock masses are procedures that require continuous adjustment of parameters and criteria to optimize the results. In this proposal we describe a set of tools that enhance decision-making for this type of jobs particularly in dam projects. The methodology is focused on hydrogeological zoning of the site and its constant update combining engineer’s experience with artificial intelligence techniques to integrate the site knowledge; as well as the evaluation of grouting results for different scrutiny scales, with special attention on the relationship between water absorption and grout consumption. INTRODUCTIONSeveral methodologies for design, implementation and evaluation for grouting rock masses have been developed for the solution of specific problems and tested in diverse geological conditions. Each of these methodologies is focused on results evaluation for different scrutiny scales (Table 1) and is employed to assist decision-making before or during the grouting process.Some methods define specifications for grouting each stage of the borehole, making theoretical, semi empirical or experience-based considerations to define basic parameters as maximum pressure, maximum volume, grouting time, flow rate, etc. Ultimately each approach aim to optimize the injection process, adjusting volumes or the grouting time required to obtain satisfactory results, reducing risk of creating new flow paths or unnecessary grout travels, and enhancing the mixture properties to achieve adequate penetrability and long-term behaviour. Some of these criteria have been widely used in dam projects, for example the concept of Grouting Based on Facts to define the maximum pressure and volume (Ewert, 1997), the GIN method (Lombardi & Deere, 1993; El Tani, 2012), or the North American standards based on Apparent Lugeon measures (Naudts, 1995; Bruce 2011); on the other hand, there are relatively new criteria that have shown good results for dam grouting as the Aperture Control Method (Bonin et al., 2012; Carter et al., 2012) or the Real Time Grouting Control Method (Stille et al., 2012)."

Jan 1, 2015

By B. T. Lu

The corrosion and wear properties of a series of chrome white iron (CWI) castings were study using electrochemical and low-stress sliding abrasion tests. The results confirm that the corrosion resistance of these materials is largely dependant on the quantity of chromium in the matrix, while the wear resistance is mainly controlled by the volume fraction of chromium carbides. A pseudo-wear/corrosion map is developed to identify alloy compositions that may be suited for erosion/corrosion conditions.

Jan 1, 2005

By Chris McBean

Due diligence mistakes ? lost opportunity ? High profile write-downs and cost overruns ? Result ? tight market for financing ? Implications for due diligence ? need to get it right ? maybe only one chance ? Where should focus be?

May 1, 2013

By T. P. Johnson, A. Vathavooran

"Conventional mining operations can produce a wide range of wastes containing gold and other precious metals but which are less suitable for processing by traditional methods. There are also types of ore that do not fit easily into a traditional processing flowsheet, e.g. because the refractory nature of their minerology or the combination of valuable metals is less suitable for traditional processes. Nevertheless, these potential sources of valuable metals remain unexploited resources that have attracted growing interest in the metals and mining industries over recent years. The challenge is therefore to develop and use alternative processing methods that have the flexibility of operation to cope with a wide variety of material types and tonnages, whilst providing high recoveries for valuable metals. Tetronics’ DC plasma smelting technology achieves industry-leading recovery rates for precious metals from a wide range of input materials and initial precious metal concentrations, whilst generating an inert slag-based material as a by-product (even when starting from a hazardous waste input material), approved within the EU for use in construction applications. This paper describes how this technology can be used as a key part of an overall process for the recovery of precious metals from these interesting materials.INTRODUCTION The extraction of gold from its ores by various forms of cyanide leaching has been practised by the mining industry for over a century (Minerals Council of Australia, 2005) and it remains the primary extraction method in a wide range of mining operations. The ability of cyanide to extract gold efficiently and quickly from lower grade ores without extensive additional processing, coupled with well-known methods to recycle the cyanide for re-use within the process mean it is often both the most economically preferable and environmentally acceptable method for recovering gold. As a result, 88% of all gold produced from mines in the USA in 2014 was recovered via leaching of open heaps or dumps (UGGS, 2016). Nevertheless, there are occasions where certain combinations of mineralogy and other circumstances reduce the effectiveness of cyanidation techniques, so that ever more elaborate additional processing steps are required, with inevitable increases in operating costs (Swash, 1988). In these circumstances, which are likely to be more common in future as ore qualities diminish, other methods of extraction may offer better alternatives. Whilst much less commonly used for Au extraction at present, pyrometallurgical methods are amongst the longest-established of these alternative approaches and merit serious consideration in such cases."

Jan 1, 2017

By K. C. Corin, Z. G. Song, J. G. Wiese

In the present investigation flotation was used as a diagnostic to understand the effects of changes to the media during the grinding stage. The observations from flotation for different media are discussed in terms of particle size distribution, water recovery, solid recovery and valuable mineral recovery. The chemical parameters; pH, redox potential (Eh) and dissolved oxygen (DO) levels were measured. A Base Metal Sulphide (BMS) ore was ground under media of different shapes and compositions to determine the effect of different rod/ball material on the flotation performance of the ore. For a given grind (D80 = 75 µm), media shape had no effect on flotation performance of a BMS ore. Different grinding media had significant effect on slurry chemical properties and flotation performance. Mild steel rods (RMMS) produced the highest solids recovery, nickel and pyrrhotite (Po) recovery, with the highest ethylenediaminetetraacetic acid (EDTA) extractable iron and the lowest DO level. Chrome steel balls and stainless steel rods produced the lowest metal recovery, EDTA extractable iron and the highest DO level. A complementary study was conducted to investigate the effect of using different grinding media compositions, viz, ceramic, forged steel, 15% chrome steel, stainless steel and a mixture of stainless steel and 15% chrome steel (50:50) balls were investigated using a Platinum Group Mineral (PGM), UG2 ore. Grinding products of five different media produced the same solids and water recovery, but the grades and recoveries of Platinum Group Elements (PGE) and chromite were different. Grinding products of ceramic media showed the best flotation performance, with the highest PGE recovery and the lowest Cr2O3 recovery. While grinding products of stainless steel balls (SS) produced the lowest PGE recovery and highest Cr2O3 grade and recovery in the concentrates.

Jan 1, 2016

By Walter I. Nelson

THE geology of the Copper Mountain mine has been ably described by Dr. Victor Dolmage in Memoir 171 of the Geological Survey. Reference is invited to that paper for a more extended description of the geology of the ore deposits than will be given here. The important orebodies of the mine occur in fragmencal volcanic rocks, parallel with and adjacent to the gabbro of the Copper Mountain stock. In the mine area, the contact strikes N.45°W. and dips either vertical or steeply co the southwest. For a distance of 500 feet or more from the contact, the fragmental rocks have been intensely metamorphosed both dynamically and hydrothermally. The dynamic effects are reflected in the foliation and fracturing parallel with the contact, which occurs throughout the mine, and the volcanic rocks within this foliated zone are, in places, highly schistose. Superimposed upon thi.s structure is a system of fine, straight, parallel frac-tures that strike nearly normal to the foliation (and contact) and dip between 65° and 75° to the north; it is with this last-described fracture system that the ore minerals are structurally associated. The fractures are mineralized with bornite and, to a considerably less extent, with chalcopyrite and some pyrite. A notable characteristic is the extreme fineness of the fractures; even in high-grade ore they are rarely larger than pencil lines. The tenor of the ore, therefore, varies directly with the fracture spacing. Replacemcnr of the host-rock between two or more fractures, varying in degree from finely disseminated sulphides to masses of nearly solid bornite up to 18 inches wide and 2 to 3 feet long, is not uncommon in the higher-grade portions of the orebodies. Two structural types of orebody are recognized in local nomenclature: the 'contact' orebodies, so-called because they occur along the contact; and 'outlying' orebodics, which are enclosed in the volcanics. The former arc tabular or lenticular bodies elongated along the strike and dip of the contact. The 'outlying' orebodies are coniform, chimney-like masses roughly elliptical in plan; with depth, their roots plunge at steep angles toward the contact. All of the orebodies are cut by a number of light-coloured granophyre and felsite porphyry dykes. These dykes-the so-called 'mine' dykes -enter the mine area from the north, curve gently southeasterly across the orebodies, and then cross the contact into the gabbro at the south end of the mine. All the dykes dip vertical to steeply east.

Jan 1, 1941

By K Morrison

Different individuals have calculated the boundary stresses around elliptical openings in an infinite elastic medium for various conditions of loading. With caution, such calculations are useful in indicating stress trends in mining. This paper illustrates an application to caving operations and suggests that abnormal field stress would have an adverse effect. Introduction GELDART and Udd (1), applying elastic theory, confirmed, and set out graphically, the stress distributions on the surface of elliptical openings with axis ratios varying from 1.0 (a circle) to infinity (a crack). The loading conditions varied from uniaxial to hydrostatic, and inclinations for the opening, with respect to the stress axis, varied from 0° to 90°. As most mine openings can be generalized into this elliptical conception, the usefulness of the presentation lies in the fact that given reasonable estimates for the stress ratio, the axis ratio, and its inclination, then the trend in stress concentrations as an opening develops can be readily approximated.

Jan 1, 1964

By A. Vervoort, A. Govaerts

Geostatistical concepts are often difficult for students to understand, even those with a strong mathematical background. One of the main problems is the link between the variation of the parameter value in space or time and the calculated experimental semivariogram. Another challenge is differentiating between directional and omnidirectional semivariograms and their interpretation. For these reasons, interactive tools were developed based on the free public domain software R. The use of these interactive tools is limited to educational situations only (i.e., to visualize basic concepts). The interactive modules can be accessed at www.bwk.kuleuven.be/geostatistics.

Jan 1, 2014

By K. M. Mayhew, G. D. Barr, T. M. McCoy, C. T. Knilans

"Teck Resources Limited (“Teck”) has developed and extensively tested on a continuous basis the CESL Technology hydrometallurgical process for treating copper and nickel sulphide concentrates, including bulk copper-nickel concentrates. Copper, nickel and cobalt are leached efficiently into solution, utilizing CESL process conditions. Total precious metals including gold, silver, platinum and palladium are recovered from the residue stream via sulphur flotation. This paper describes the CESL Technology testwork on a bulk copper-nickel concentrate derived from Twin Metals Minnesota?s (TMM) deposits within the Duluth complex and evaluates the economic benefits (increased cash flow, increased revenue certainty) and investment criteria (capital cost, payback and cash flow) of incorporating CESL Technology into the staged development of TMM?s deposits.INTRODUCTION Mineral Processing and the Role of Hydromet in the Duluth Complex The Duluth Complex in northern Minnesota, United States (US), represents one of the largest undeveloped accumulations of copper, nickel, gold, and platinum group metals (PGMs) in the world, ranking second in copper and PMs and third in accumulation of nickel. The figure below identifies some of the larger known deposits within the Complex (see Figure 1). Copper, nickel, PM and PGM mineralization within the Duluth Complex is hosted by mafic to ultramafic intrusive rocks that are part of the overall intrusive complex.One of the mineral processing challenges of Cu-Ni-PM-PGM deposits in this Complex is the complicated, polymetallic nature of the mineralization1: copper occurs primarily as chalcopyrite and cubanite with minor occurrence of talnakhite; nickel occurs as pentlandite and refractory nickel oxide/silicates; iron sulphides are present as both pyrrhotite and troilite; and PMs/PGMs occur in both the sulphide matrix as well as discrete minerals. An additional challenge for the Duluth Complex is the ratio between copper and nickel; in most of the identified deposits, copper grade is three to four times greater than the nickel grade, which precludes the production of a simple bulk concentrate due to the lack of a traditional smelting market for a bulk concentrate of this character."

Jan 1, 2017

By G. P. Gu, B. Fang, R. W. Revie, M. Elboujdaini

Stress-corrosion cracking (SCC) tests were conducted in the near-neutral pH standard solution, NS4, and in an actual soil solution, using four-point bending at high a stress ratio and low frequency conditions very similar to those of operational pipelines. Pitting incubation appeared first and then pitting initiated and grew in both solutions although there were many more pits on the specimen tested in soil purged with 5% CO2 + 95% N2 than in the specimen tested in NS4 solution purged with the same gas. These observations show that samples in soil solution are more susceptible to pitting than those in NS4 solution. When the pit reached a critical size, the increased stress concentration around the pits, resulted in the transition to a crack.

Jan 1, 2005

By E. Ghali, N. Sorour, G. Houlachi

"The binary Fe53Mo47 and ternary Fe54Mo30P16 coatings have been electrodeposited from citrate-based electrolyte on mild steel (MS) substrates. The electrodeposition has been conducted for 6 hours at 20 mA cm-2 and 30°C. The electrochemical tests were carried out in chlorate solutions containing 300 g L-1 NaCl and 4 g L-1 K2Cr2O7 at pH 6.4 and 80°C. A number of surface characterization techniques such as SEM-EDS, XRD and EMP were used to study the microstructure of the alloys. The electrocatalytic activity of these coatings was investigated using steady-state polarization and galvanostatic technique. This study revealed that the Fe-Mo-P coating could be considered as a promising cathode material for the hydrogen evolution reaction (HER). The results showed an important decrease of hydrogen overpotential for Fe-Mo-P alloy as compared to that of Fe-Mo and especially MS which is a traditional cathode in chlorate industry. The HER overpotential for Fe54Mo30P16 at current density of 250 mA cm-2 was decreased by 30% in comparison to that of MS (1029 mV), and by 16.5% to that of Fe53Mo47 coating (857 mV).INTRODUCTIONSodium chlorate is used for manufacturing of several daily consumption products. This chemical is mainly employed for the production of chlorine dioxide (ClO2) that is a bleaching agent used in the pulp and paper industry. The ClO2 is also consumed for generation of perchlorates, chlorites and other chlorates, as an herbicide and in uranium processing (Cornell, 2002). Sodium chlorate is produced industrially via following overall formula in un-divided electrochemical cell (Nylén & Cornell, 2009):"

Jan 1, 2016

By R. J. A. Fricker

IT is the purpose of this essay to give a reasonably complete description of shaft sinking under a rock pentice in a small Northern Ontario gold property. Hallnor is in many ways an exceptional mine, but the sinking operations here described are but typical examples of the excellent practice for which Canadian mines and mining engineers are justly famous the world over. The worth of the subject lies, therefore, nor in its originality, but in its soundness; not in the spectacular, but in the economical and safe. Attention is particularly drawn to the excellent safety record and to the exceptionally low overall sinking cost. INTRODUCTION Prior to April, 1939, the Hallnor No. 1 shaft had been sunk vertically to a depth of 997 feet below the surface. It is a three-compartment shaft, 19 ft. 10 in. by 7ft. 7 in. outside the timbers (see Figure 1).

Jan 1, 1941

By Kyle Paulsen

The Cameco Key Lake mill began processing U-bearing waste rock from the McArthur River mine in 2000. This ore often contains elevated levels of calcium (>4% by mass), resulting in less than favourable conditions in parts of the Key Lake mill, yet still contains U3O8 at a concentration of about 0.3%. To recover the U3O8 and reject as much calcium as possible, modifications were made to the grinding circuit in late 2007 to include a gravity concentrator. The concentrator allows this mineralized waste to be processed separate from the regular blend material, rejecting calcium and concentrating U3O8, thus improving the operating conditions in areas such as SX. This will be presented in greater detail along with results and further work.

Aug 1, 2010

By F. A. Auld

"During the period 1958-1980 seven deep shafts were sunk from the surface in the UK. From 1977 until 1989 sixteen deep shafts were sunk in the UK, all concrete lined. Subsequently from 1989 up to the present day no deep shafts have been sunk in the UK, a period of 30 years. Developments in the design and construction of deep shaft linings in the UK therefore were predominantly carried out throughout the period 1977–1989. This knowledge is recorded in several published papers by the author over that period which will be referred to in the paper. INTRODUCTION The paper includes a review of past precedent for the design of deep shaft concrete linings in the UK and sets out the principles for future designs, including the design load to be adopted and Factors of Safety (SFs) to be used in the design. Hydrostatic pressure increases with depth from the surface and therefore the concrete lining must increase in thickness and strength throughout its depth to resist the pressure. High strength concrete mixes were developed to enable economic linings to reach greater depths and these will be detailed. The ground conditions to sink through in the UK consist of predominantly competent (self-standing when excavated) rock, which can be water bearing, and hence a hydrostatic pressure resisting lining is required. The paper describes the construction measures needed to produce a dry shaft by way of pour length, joint detail, backwall grouting and joint sealing details. PAST PRECEDENT FOR UK DEEP SHAFT SINKING AND LINING Seven deep shafts were sunk from the surface in the UK from 1957–1977 over a 20-year period (Auld, 1987). These are listed in Table 1. Three shafts were for British Coal, two were for Cleveland Potash Ltd and two were for the Central Electricity Generating Board. The British Coal shafts were 5.486 m and 7.315 m internal diameter to depths of 550 m and 780 m, respectively. At 5.5 m internal diameter and a depth of 1150 m, the two Boulby Mine shafts for Cleveland Potash Ltd are currently the deepest shafts in the UK. The two Central Electricity Generating Board shafts of 5 m and 10 m internal diameter, to depths of 255 m and 440 m, respectively, were ventilation shafts for a pumped storage scheme. Six of the shafts were sunk by Thyssen (GB) Ltd and one by Cementation Mining Ltd."

Jan 1, 2019

By Z. Z. Öztürk, N. Sarica, A. H. Üçisik, C. Bindal

"Titanium oxide films were fabricated on commercially pure titanium surfaces via anodization procedure. Anodization parameters, anodization time and voltage were altered, whereas temperature and chemical composition of anodization bath were kept constant. The main idea in this study is to obtain rough titanium-oxide surfaces. The type and feature of titanium oxide formed were observed via SEM and EDX analyses. What was revealed from SEM and EDX analyses were combined with Ti-O phase diagram in order to make judgment on the type of phases obtained, e.g. solid solution and/or compounds. Studies on the different regions of each sample showed that surfaces consist of different titanium oxide compounds with various O/Ti ratios in nano level and solid solutions varying in terms of chemistry on the same sample. Thus together rough surfaces and inhomogeneous distribution of "titanium oxides" were obtained. It was also found that when anodization time and voltage were increased, more granular surface with higher O/Ti atomic ratio was obtained."

Jan 1, 2015

By Z. Abbasloo, A. Masoomi, L. Ebrahimi, A. Mortazavi, A. Keshavarz

"Investigation and 3D analysis of Heap no. 2 of Meydook copper complex was the subject of this study. In this project all geological and geotechnical investigations conducted in the mine were evaluated aiming at determination of Heap no. 2 design parameters. The main objective of the project was to evaluate the potential for construction of Heap. No. 2 on a waste dump built in a valley in the north side of the pit.Considering the space limitation for dump location this was a viable alternative to reduce the costs associated with heap no. 2 construction. Moreover, it allowed for a significant reduction in overall mining costs. Considering the project condition, a 3D analysis of heap major structures including; valley rock foundation, waste dump, and low grade ore was carried out. Five sets of analyses were conducted and the displacement and stress fields were calculated within the heap no. 2 components. In all analyses conducted the subsident profile was determined for the valley base rock and heap foundation (waste dump). Moreover, the shear interaction between heap and waste dump was evaluated at the heap interface. The analyses results showed that the maximum settlement at the heap base is about 4-5 cm and the waste dump provides a safe and reliable base for heap construction. Moreover, the analysis results showed that the selected %5 grade for the heap interface is good and does not pose any risk in terms of heap Interface shear displacements. A sensitivity analysis of heap mechanical parameters was also conducted. The obtained results show that if the friction angle of heap material is reduced below 25 degree due to acid spraying process, the heap walls become unstable and the heap geometry must be redesigned."

Jan 1, 2015

By D. A. Beattie

Talc is a commonly encountered gangue mineral in metal sulfide flotation. Talc is naturally hydrophobic, resulting in high recoveries if polymeric depressants are not used to specifically reject this MgO containing mineral. We have studied the adsorption of a selection of polymers onto talc using a variety of techniques. Adsorption isotherms have been determined using ex situ depletion techniques and in situ ATR-FTIR spectroscopy has been used to determine adsorption kinetics. Adsorbed layer thicknesses have been determined for the polymers on cleaved talc surfaces using the AFM. The effect of the adsorbed polymer layer on the properties of the talc surface has been quantified through contact angle measurements and single mineral flotation tests. Distinct correlations are observed between the adsorbed layer properties and the flotation performance of the polymers. These observations are discussed with reference to the bubble-particle attachment process and the molecular structure of the polymers.

Jan 1, 2006

By J. R. Fisher

"Uranium may be leached to some extent in situ from the Blind River conglomerate uranium ores by using the products of bacterial activity from the bacterium Thio-bacillus ferrooxidans his paper describes some of the laboratory techniques used to investigate the characteristics of the bacteria, and to utilize their properties in uranium leaching. The application of some of the laboratory results underground at the Milliken mine of Rio Algom Mines Limited are de-scribed, along with the method of uranium recovery from the mine waters."

Jan 1, 1966