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By L S. Shekhawat, M P. Roy, R K. Paswan, P K. Singh, A Joshi

Blasting in the mining industry is being transformed, and can no longer be treated as an art or a practice purely dependent upon experiences of individuals. Examples of key drivers that have demanded consistent and more accurate blast results are initiatives to control pit-wall damage to help mine steeper pit slope angles, to control damage to underground opening operating in close vicinity of the open pit mine. Such situation exists at Rampura Agucha open pit lead zinc mine, which is producing 5.7 Mt/a of ore and has started its underground part, which is slated to produce initially 2–2.4 Mt/a and 4.5 Mt/a in the near future. The open pit mine is currently working at 326 m depth and is designed to reach 421 m deep. It has been planned to operate the underground mine maintaining 50 m parting from the planned ultimate level of the open pit mine.Presently, open pit and underground mines are being operated simultaneously. The present average depth of underground working lies between 370 and 410 m below the surface level. Sometimes explosives up to 95 978 kg are being detonated in a blast round in open pit mine. These blasts are often apprehended as a danger to the safety and stability of underground openings. It was decided to document the impact of open pit blasting in the openings of underground workings, so that preventive measures may be taken for the safety and long-term stability of the underground mine. The impact of 86 open pit blasts has been documented in the underground openings and 258 blast vibration data has been recorded. The vibrations were recorded simultaneously in the roof, side walls and at floor levels. The highest levels of vibrations were recorded in the roof and the lowest levels at the corresponding floor levels. The pillars experienced lower level of vibrations than the roof. Blast designs were optimised at open pit mine to control vibration in view of long-term safety and stability of the underground openings. The vibrations generated due to detonation of explosives with shock tubes and electronic delay detonators have been recorded in underground openings for comparative assessment. Ground vibration recorded at roof, pillar and floor were analysed separately and threshold value of the vibration for the safety of underground workings has been determined based on the rock mass rating of the roof rock.CITATION:Singh, P K, Roy, M P, Paswan, R K, Shekhawat, L S and Joshi, A, 2015. Protection of underground mine structures due to adjoining open pit mine blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 279–288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Fejes A. J

The U.S. Bureau of Mines installed surface and subsurface instruments at a mine site in Colorado to monitor and characterize the overburden response to longwall mining. Instrumentation included a time-domain reflectometry (TDR) cable, a multiple-point borehole extensometer (MPBX), vertical- deformation surface monuments, and in-mine pressure cells for monitoring abutment, pillar, and gob loads with respect to the longwall face position. The purpose of the study was to collect data that could be analyzed to correlate the design of the mine layout to the resulting overburden failure response. Determining the extent of caving and fracturing is important in the and and semiarid Western United States because of the possible consequences to the fragile underground hydrologic systems upon which the land owners and users depend. This study is unique from past investigations because the overburden contains massive sandstone members that impose special conditions on the caving process and pressure redistribution above the longwall panels. This paper presents the results of this correlation study.

Jan 1, 1992

By Khamis Y. Haramy

The U.S. Bureau of Mines installed surface and subsurface instruments at a mine site in Colorado to monitor and characterize the overburden response to longwall mining. Instrumentation included a time-domain reflectometry (TDR) cable, a multiple-point borehole extensometer (MPBX), vertical-deformation surface monuments, and in-mine pressure cells for monitoring abutment, pillar, and gob loads with respect to the longwall face position. The purpose of the study was to collect data that could be analyzed to correlate the design of the mine layout to the resulting overburden failure response. Determining the extent of caving and fracturing is important in the arid and semiarid Western United States because of the possible consequences to the fragile underground hydrologic systems upon which the land owners and users depend. This study is unique from past investigations because the overburden contains massive sandstone members that impose special conditions on the caving process and pressure redistribution above the longwall panels. This paper presents the results of this correlation study.

Jan 1, 1992

The financing of mineral ventures is usually supported by the valuation of a mineral asset, the physical size and composition of which have been determined within quantified limits of accuracy in order that the lending or investment risk can be assessed. The Resource or Ore Reserve estimation is the measurement of that asset and may be the outcome of complicated processes of interpretation and estimation requiring an extensive knowledge and understanding of the general nature of ore occurrences, and of the particular deposit under review. In arriving at an interpretation of the nature and physical distribution of minerals in a deposit, observations may only be available from widely spaced samples and geological knowledge and principles are of prime importance. Consultants may be asked by the lending or investing body to "provide comfort" on the quality of the Resource or Reserve estimations and providing such comfort casts substantial obligations of diligence on the consultant.

Jan 1, 1990

By Ben DiFiore, Richard DePew, Nate Long, Adrian Naranjo-Castillo, Chris Petta, Robert Auber

The Walworth Run stream was brick-culverted in the 1800s, converting it to a 16-ft diameter sewer. This Cuyahoga River tributary contributed to the infamous burning river that became the catalyst for USA’s environmental movement. The NEORSD has been working hard to reduce CSOs here, most recently by diverting Walworth Run’s 882 MGD of flow to the new Westerly Tunnel. This had to consider structure age/size, alluvial/glaciolacustrine deposits (requiring several ground support systems, groundwater control), and maintenance of massive flows. This paper examines challenges identified during design that supported the contractor in development of a risk-mitigating plan, culminating to successful implementation.

Dec 1, 2022

By Harold B. Janzen, M. A. Nobles

Campbell and Martin1 described a new exploratory logging tool which was developed as the result of a new concept of the phenomenon that takes place when a porous formation containing mobile hydrocarbons and irreducible interstitial water is invaded by mud filtrate. They postulate that invasion will create a bank of interstitial water between the flushed zone and the undisturbed formation. This postulate was confirmed by Wyllie.' Thus, if R,, is greater than R, and mobile hydrocarbons are present, the resistivity profile with increasing radii from the borehole is high:low:high, as shown in Fig. 1. If mobile hydrocarbons are absent, the bank of interstitial water is indistinguishable from the undisturbed formation and the resistivity profile, when R is greater than R,, is high:low, as shown in Fig. 2. The zone containing the bank of interstitial water and residual oil was named the "low zone". Campbell and Martin conducted extensive electrolytic wedge and resistivity analog model studies to select a logging system that would reflect the presence or absence of the low zone. The system they selected was that of a family of lateral curves. The model studies indicated that the presence of a low zone could be detected in approximately 60 to 70 per cent of the producing sand reservoirs with a family of lateral curves provided that the sonde effectively occupies 90 per cent of the diameter of the hole. These studies were conducted with D, = 5d. The presence or absence of the low zone is best determined by a plot of the apparent resistivity vs spacing as shown in Figs. 3 and 4. A dip or inflection in the profile that repeats at successive depth intervals is considered diagnostic. To reduce the shunting effect of the hole and mud, a sonde of insulating material that is surrounded by a series of flexible rubber bumpers was designed. The bumper efficiency is considered to be the ratio of the bumper diameter to the hole diameter. Field tests conducted by Campbell and Martin on 10 wells with a tool that provided for station readings indicated that dips or inflections could be detected in 19 out of 25 known producing zones. INSTRUMENT DEVELOPMENT Halliburton developed a logging system to simultaneously and continuously record eight lateral curves. The instrumentation is described in the literature.' The original logs made

By Rollin E. Hook, Attwell M. Adair

The response of CrzO3 and C~304 to various heat treatments was studied in are-melted iodide chromizim over the temperature range 1000" to 1750°C. These oxides, which are present as impurity phases in this material, were identified by X-ray diffraction teclzniques which were supplemented by optical metallop-aphy. As a function of increasing temperature, Crs04 is first observable in samples annealed at 1300°C and coexists with Cr2O3 (the low-temperature oxide) over a temperature range exceeding 200°C. As the temperature decreases, Cr3O4 dissolves with the concomitant precipttation of Cr2Y2. Both oxides precipitate predominantly at pain boundaries. The reactions which occur are involved with at least ternary equilibria, possibly due to iron which is present as an impurity in arc-melted iodide chromium. HILTY, Forgeng, and Folkman' reported in their investigation of the Fe-Cr-0 system that Cr3O4 (with about 8 pct Fe substituted for chromium) is a primary phase found in alloys with 9 or more pct Cr. They reported that this phase is stable only at high temperatures and that below the liquidus Cr3O4 is disproportionated into Cr2O3 and chromium-rich metal for both Fe-Cr-O alloys and in oxygen saturated pure chromium. Further, they proposed that CrsO4 forms by a peritectic reaction between Cr2O3 and the liquid. On the other hand, Hook, Garrett, and Adair2 found in their investigation of impurity phases formed in "pure" chromium (material consolidated from iodide chromium crystals) that Cr3O4 forms intergranularly and is stable as low as 1500°C which is 375OC below the melting point of chromium. The purpose of the research described herein is to determine the temperature range of stability of Cr3O4, and to show the nature of its decomposition. This further investigation indicates that Cr3O4 undoubtedly occurs in this material as low as 1300°C. The chromium studied was consolidated and fabricated from iodide chromium crystals (ICr-5) and contained Fe r 135 ppm, Si = 20 to 100 ppm, and 0 = 35 to 137 ppm. A complete chemical analysis is given elsewhere.' Annealing was conducted in 1 atm of purified helium and all samples were rapidly cooled (-200°C per sec) by withdrawing them from the furnace hot zone under a high flow rate of helium. The details of the electrolytic-etching technique and electrolytic-digestion techniques for preparation of insoluble residues for X-ray examination are given elsewhere also.' EXPERIMENTAL RESULTS The Starting Material. The as-swaged rod (final swaging done at 900°C) had a wrought grain structure and contained a dispersion of CrzO3 inclusions of maximum particle size of about 2 or 3 p, Fig. 1. The microstructure also contained a dispersed

Jan 1, 1964

By Howard Drullard

To OBTAIN the best results from hammer drills, close attention must be paid to two factors in drill maintenance, which are of equal importance; one is lubrication, the other is the shank. With the exception of stoping drills, most modern rock drills require both oil and grease. The oil ports are in the lubricator, on or behind the hammer cylinder; the grease port for the lubrication of the 'chuck sleeve and rotating mechanism is on the chuck end. Ordinary machine oil is not, adapted to rock drills; a heavier more gelatinous oil such as castor machine oil or liquid-grease should be used. The lubricators should be filled-once for every 12 or 14 ft. (3.5 to 4m.), of hole drilled. Grease-guns should be used to fill the port in the chuck end once a shift; a medium ( No. 3) grease is well adapted to this purpose. Hard grease must not be put into- the lubricators, as it will not flow through that part. Contrary to the popular belief, oiling a machine once or twice a shift does not provide sufficient lubrication; the drills should be oiled once for every 12 or 14 ft. of, hole drilled. The rotating handle of a stoping drill -is an oil reservoir and is provided with a port for oiling. The rotating handle is packed with wicking, or similar material, which causes the oil to feed slowly from the handle to the other parts of the machine. Stoping drills require oil at. least twice a shift; lighter oils than castor, such as Arctic Ammonia may be used.

Jan 8, 1920

By Vincent Thorne

On January 2, 1992, the R. Zoppo Company of Stoughton, Massachusetts started drilling and blasting operations on U.S. Army Corps of Engineers Project Number: DACW33-91-B-0072 to widen and deepen the Portsmouth Harbor and Piscataqua River Navigation Channel.

Jan 1, 1993

By F. L. Toy, C. E. Sims

I. A. Sirel—I would like to ask Mr. Sims what would the preferred hot metal analysis be as far as manganese and silicon are concerned if you used specially made iron for this process instead of basic iron. C. E. Sims (authors' reply)—A preferred composition would contain somewhat less silicon than the basic pig iron used in these experiments. High silicon requires a large lime addition. Lime must be added in sufficient quantity to neutralize the silica formed and to leave an excess for dephosphorization. Manganese presents almost no problem in operation. It is almost completely oxidized and, in burning, develops considerable heat. The evidence indicates, however, that, in continuous commercial operation, there will be an excess of heat produced, and the bath will need to be cooled in some manner as by the addition of scrap or by utilizing the energy for the direct reduction of ore. There do not seem to be any serious limitations on composition of pig iron. One heat was made with an iron containing 2.27 pct silicon and the phosphorus finished at 0.007 pct. In another, the iron contained 0.45 pct phosphorus which was lowered to 0.019 pct. This indicates considerable leeway in composition. D. R. Loughrey—We are all very much interested in the recent discovery of very large deposits of iron ore both in Labrador and in Venezuela. I would like to ask Mr. Sims if the iron ore at either or both of these places is such that it would lend itself to the manufacture of iron suitable for use in the turbohearth. C. E. Sims-—According to my information, those ores are not essentially different from ores now used in this country for making basic pig. They should, therefore, be adaptable to this process. D. I. Brown—You have spoken about the leeway, or spread in analysis of the various irons you can use in the vessel. I would like to have you tell us, if you can, about the different kinds of steels which can be made in such a vessel. The turbohearth process, or it might more aptly be called pneumatic openhearth, is a little different from that used in most Bessemer shops and in the one in which I worked. If we had a blow in the air over 10 min, the boss was in the pulpit in a hurry

Jan 1, 1951

By D. W. Akins

The case history of a combination gas and water flood instituted early in the life of a field is described. It was recognized from the beginning that recovery would be low, under normal production methods, from the several separate, thin beds of porous limestone which had such poor native permeability that the wells would not produce without acidizing. It is thought that the combination flood gives excellent recovery efficiencies for this type of reservoir. The chief function of the gas flood now is to maintain bottom hole pressure in that part of the reservoir which will not be affected by the water injection program until later. Present estimates are that ultimate recovery will be approximately double the recovery expected under the original solution gas drive mechanism. Wide (80-acre) spacing has enhanced the economics of the over-all field program by the elimination of more than $5,000,000 worth of unnecessary wells. INTRODUCTION The Haynesville Pettit Field was discovered in November, 1941, with the completion of T. L. James Co.'s Callie Akin No. 1, located in the W 1/2 of the NE 1/4 Section 27-23N-8W, Claiborne Parish, La., at an approximate depth of 5,300 ft. The center of the field is about two miles north and a mile west of the town of Haynesville, La. A total of 189 producing wells have been drilled on 14,500 acres. An additional nine dry holes were drilled. The Louisiana-Arkansas state line divides the field so that 34 wells are in Arkansas and 155 are in Louisiana. Governmental sections are divided equally to contain eight production units making 80-acre spacing where the sections are regular. Along the state line in Louisiana there is an irregular tier of sections, each of which contains approximately 456 acres. When divided equally into eight production units the spacing is 57 acres per well for these three and a fraction productive sections. All Haynesville Pettit wells are identified by their section number followed by their position in the section as determined by numbering the production units counterclockwise beginning in the upper right corner of the section. All of the producing wells in the field except two are unit-ized and operated by the Haynesville Operators Committee. These two wells are located in the extreme northern part of the field in Arkansas. Efforts to bring them into the Unit are being continued. The Pettit operators organized the Haynesville Operators Committee and the field became a unit operation May 1: 1944. GEOLOGY The Pettit is Lower Cretaceous in age and is defined as the uppermost porosity in the Sligo formation. The unitized area known as the Haynesville Pettit Field is composed of two separate zones of porosity approximately 40 ft apart and without connection between the two, except in wells. These zones are known as the Upper Pettit and the Lower Pettit. The Upper Pettit is separated into two sections throughout most of its area by a relatively thin but quite impervious shale streak. These are called the "A" and "B" sections of the Upper Pettit. All of these lenticular zones are composed of coquina limestone and a small percentage of normal oolites. The large

Jan 1, 1951

By D. W. Akins

The case history of a combination gas and water flood instituted early in the life of a field is described. It was recognized from the beginning that recovery would be low, under normal production methods, from the several separate, thin beds of porous limestone which had such poor native permeability that the wells would not produce without acidizing. It is thought that the combination flood gives excellent recovery efficiencies for this type of reservoir. The chief function of the gas flood now is to maintain bottom hole pressure in that part of the reservoir which will not be affected by the water injection program until later. Present estimates are that ultimate recovery will be approximately double the recovery expected under the original solution gas drive mechanism. Wide (80-acre) spacing has enhanced the economics of the over-all field program by the elimination of more than $5,000,000 worth of unnecessary wells. INTRODUCTION The Haynesville Pettit Field was discovered in November, 1941, with the completion of T. L. James Co.'s Callie Akin No. 1, located in the W 1/2 of the NE 1/4 Section 27-23N-8W, Claiborne Parish, La., at an approximate depth of 5,300 ft. The center of the field is about two miles north and a mile west of the town of Haynesville, La. A total of 189 producing wells have been drilled on 14,500 acres. An additional nine dry holes were drilled. The Louisiana-Arkansas state line divides the field so that 34 wells are in Arkansas and 155 are in Louisiana. Governmental sections are divided equally to contain eight production units making 80-acre spacing where the sections are regular. Along the state line in Louisiana there is an irregular tier of sections, each of which contains approximately 456 acres. When divided equally into eight production units the spacing is 57 acres per well for these three and a fraction productive sections. All Haynesville Pettit wells are identified by their section number followed by their position in the section as determined by numbering the production units counterclockwise beginning in the upper right corner of the section. All of the producing wells in the field except two are unit-ized and operated by the Haynesville Operators Committee. These two wells are located in the extreme northern part of the field in Arkansas. Efforts to bring them into the Unit are being continued. The Pettit operators organized the Haynesville Operators Committee and the field became a unit operation May 1: 1944. GEOLOGY The Pettit is Lower Cretaceous in age and is defined as the uppermost porosity in the Sligo formation. The unitized area known as the Haynesville Pettit Field is composed of two separate zones of porosity approximately 40 ft apart and without connection between the two, except in wells. These zones are known as the Upper Pettit and the Lower Pettit. The Upper Pettit is separated into two sections throughout most of its area by a relatively thin but quite impervious shale streak. These are called the "A" and "B" sections of the Upper Pettit. All of these lenticular zones are composed of coquina limestone and a small percentage of normal oolites. The large

Jan 1, 1951

By F. H. Wilson, E. W. Palmer

G. L. Bailey (British Non-Ferrous Metals Research Association, London, England)—I was glad to see this further work on the structure and properties of the Cu-Ni-Fe alloys of low nickel content in which we have been so interested in the United Kingdom since before the war." The authors' data on the variation in solubility of iron in both 5 and 10 pct Ni alloys with temperature is based on more detailed observations than we have made but is generally in line with our own work. The difficulty in these matters is in the identification of the structures obtained. The precipitation of the second phase which we presume to be the a' solid solution, richer in nickel and iron, from the a solution with which it is in equilibrium occurs in such a fine state of division that its resolution by ordinary micro-graphic methods is impossible in the early stages. We have published some electron micrographs which illustrate the effects observed more clearly but we agree with the authors when they say that dark staining characteristics when the alloys are subjected to sea-water corrosion are more sensitive in detecting the presence of the a' phase than is the microscope. After taking this point into consideration, however, I confess to some difficulty in understanding Fig. 4. I can only assume that the precipitates visible at such a low magnification as 150 diam in these relatively coarse forms are produced from iron-rich areas of the initial solid solution due to inadequate homogenization. If this is so I find it difficult to accept the authors' contention that such local variations in iron concentration as are capable of giving the heavy precipitates shown in Fig. 4 do not in fact materially affect the solvus surfaces of their equilibrium diagrams. I share the authors' enthusiasm about the resistance to corrosion of these alloys by seawater but I am not fully in agreement with them on the vexing question of the best iron content for these alloys. In Fig. 3 of ref. 8, we give many results showing that the resistance of these alloys to impingement attack in the Jet Test increases as the iron content rises to 2 pct. With higher iron contents pitting at shielded areas is likely to occur. Admittedly the addition of 0.75 pct Fe produces a large improvement in corrosion resistance compared with a pure 90/10 Cu-Ni alloy, but the further improvement on raising the iron to 2 pct is substantial. We recommend from 1.5 to 2 pct Fe as the desirable range from the point of view of corrosion resistance. While it is true that British practice generally uses a hard tube, the corrosion resistance of the 10 pct Ni alloys has in our work been little affected by the structural condition. Although the annealed alloys blacken in seawater, this effect seems to be superficial and not to be accompanied by any real decrease in

Jan 1, 1953

Reducing Fusion: The impure or low grade uranium concentrate is mixed with a formulated flux of sodium carbonate, salt, and sawdust or fuel oil and heated, while being stirred, to about 950°C. This reduces the uranium to the black, water insoluble uranium dioxide and with the exception of nonamphoteric metals forms water soluble sodium salts of the vanadium, alumina, silica, phosphates, and other constituents of the cake. The cooled melt is then water leached, leaving a residue of black insoluble uranium dioxide. "Green Sludge" Digestion and Liquor Purification: The green sludge is redissolved in acid, and by selective precipitation involving pH adjustments and a final neutralization

Jun 1, 1956

By L P. Trout, D G. Reid

PanAust Limited (PanAust) has successfully constructed and commissioned two mining operations in Lao PDR over the past decade and undertaken major studies for three new mine developments. The management of potentially acid generating mine waste and tailings in close proximity of local communities sensitive to water discharge quality have been recurring themes that have confronted PanAust’s project study, development and operational teams. Further compounding challenges, such as the effects of intense annual tropical monsoonal conditions, staging of embankment raises and regular lifting of spillway structures, integrating mine waste and tailings management into production plans and ensuring the long term stability of structures, have been addressed by implementing leading practice management solutions.A recognition of the criticality of managing the substantial business risks associated with these crucial activities led to the early establishment of a governance structure to ensure that the highest standards are embraced for planning and execution. Importantly, these are guided and monitored by a panel of highly experienced and qualified international specialists reporting directly to PanAust’s Managing Director – the Tailings Independent Review Panel. The stewardship process has been effective in identifying potential shortcomings in management systems and has led to enhanced executive commitment to risk informed designs, assurance and overall process rigour.CITATION:Trout, L P and Reid, D G, 2018. PanAust Limited’s approach to mine waste and tailings stewardship, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 135–155 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By G. E. McElroy

[During the period July, 1923, to April, 1924, we made a large number of careful determinations of the resistance to the passage of air in selected sections of airways in the metal mines of Butte, Mont. The experiments were conducted with the cooperation of the Anaconda Copper Mining Co., Frank D. Cannon, mining engineer of that company, and Fred P. Gaethke, mining engineer of the bureau, assisted in carrying out this work. This paper summarizes the, main group of data obtained in the form of a table, of friction factors, or coefficients of friction that is, values of K in the generally accented formula or air flow of [P = KSV or H = KSV2 ] where, in units customary to mining practice;]

Jan 1, 1925

By V. T. McLemore

The Steeple Rock district in New Mexico is a major epithermal gold-silver district that exhibits district zoning. Five types of ore deposits occur within the district: •base-metal veins (with gold and silver) form the center of the district and occur along the Carlisle fault, •gold-silver veins along northwest-trending faults and outward from the base-metal veins, •copper-silver veins along the margins of the district, •fluorite veins along the margins of the district, and •manganese veins along the margins of the district. Areas of older acid-sulfate alteration occur throughout the district and also exhibit the following zoning: massive silica/chert zone (inner), silicified zone and clay zone (outer). This alteration overlies regional alkali-chloride (propylitic to argillic to sericitic) alteration. Synthesis of available data suggests the acid-sulfate alteration is related to a shallow, but older, epithermal hot-springs system. Subsequently, younger epithermal veins formed along faults.

Jan 1, 1996

By L. A. Cisternas, R. I. Jeldres, C. Cruz, P. A. Robles

"Previous studies have shown that the floatability of chalcopyrite in seawater at highly alkaline conditions is significantly affected by the presence of clays. The reason is that the species of calcium and magnesium present in seawater under those conditions may act as a bridge between the surfaces of clay and chalcopyrite, generating massive aggregates that then depress. In this context, the objective of this work is to analyze the impact of pretreated seawater with low amount of calcium and magnesium ions on the recovery of a sulphide copper mineral with high kaolinite content as clay. The seawater pre-treatment is done by the addition of sodium hydroxide in a high carbon dioxide environment. The chemical reactions realized under these conditions lead to the formation and precipitation of calcium and magnesium species that are subsequently removed by vacuum filtration. The pre-treated seawater is then used in flotation tests at pH 11 for copper sulphide, where the mineral is synthetically prepared by mixtures of chalcopyrite, kaolinite, and quartz. When comparing the flotation results for different types of water, including seawater and pre-treated seawater, a significant effect is observed: as the seawater hardness decreases, which comprises the calcium and magnesium ions, the recovery of chalcopyrite is increased. However, the effect is markedly enhanced in the presence of kaolinite. Therefore, the results indicate that sodium hydroxide and carbon dioxide are able to remove different species of calcium and magnesium from seawater and could improve the chalcopyrite recovery with high kaolinite content. INTRODUCTIONIn many cases, mineral deposits are found in arid areas with little access to water resources. Water is a fundamental element to carry out the unit operations that achieved the separation of valuable minerals (especially in concentration operations). Seawater has acquired an interesting role in recent years (Cisternas and Moreno, 2014); in fact, it seems to be one of the few viable options to ensure the sustainability of the mining industry in arid zones. At present, there are numerous experiences of industries that use or have used this resource, either by submitting the seawater to a desalination treatment by reverse osmosis or by applying it directly, without desalting. The latter case may involve significant economic benefits (for example, by avoiding the investment of building a desalination plant) and in some cases some operational benefits. A positive aspect is that in general terms the foaming in the saline medium is much more efficient compared to fresh water (Quinn et al., 2014; Castro et al., 2010). Some reports show that the foaming doses required to achieve a certain quality of bubbles are remarkably reduced, reaching exceptional cases such as Xstrata's Raglan concentrator, where it did not even include foaming to carry out the operation. This fact is quite promising, considering that some researchers have stated that controlling the quality of bubbles and foam could float minerals through coarse particles. This would lead to multiple benefits, such as energy savings by avoiding excessive grinding and a lower presence of fine ore that causes major problems in water recovery operations by gravitation (such as thickening) and in tailings management. However, seawater also causes significant challenges in multiple operations (Jeldres et al., 2017, 2016; Castro et al., 2010), as for example in minerals with high clay content (Uribe et al., 2017). In fresh water, the presence of clays minerals in ores is already a major problem in the flotation stages since the operation becomes difficult to be controlled, and operators are commonly forced to increase the consumption of reagents because the collectors are deposited on the clays' surfaces reducing froth stability (Farrokhpay and Bradshaw, 2012). Sometimes the use of rheology-modifying reagents should also be incorporated since the pulps become more visc"

Jan 1, 2018

By E. L. Montgomery

Salar basins in the Andean Highlands of Northern Chile contain ground-water resources which could be used to satisfy requirements for the mineral industry in the region. Salars occur in arid zones; average precipitation is about 200 millimeters per year at altitudes of about 4,000 meters, and average annual evaporation is two meters or more. The salar basins are hydrogeologic sinks where water flows from recharge areas at the margins of the basins to discharge areas at the salt encrusted salar at the lowest point of the basin floor. Groundwater circulation occurs principally in the alluvial and fractured bedrock aquifers. Results of pumping tests for exploration and production water wells indicate a range in maximum sustained pumping yield of 62 to 126 liters per second, and where abundantly fractured, ignimbrite comprises the most prolific aquifer. Chemical quality of groundwater is good. Long-term pumping from properly located production wells in the salar basins would result in lowering of groundwater levels and salvage of water in areas where groundwater is lost via evaporation.

Jan 1, 1986

By D Laurence

Significant developments in future mining systems, technology and best practices are emerging that are driven by issues relating to human resources, competitiveness, environmental and social responsibility, within the dynamics of globalisation. It is proposed that the definition of the role and attributes of the mining engineer in the mine life cycle needs to be viewed more holistically in the face of increasingly more diverse and complex responsibilities. These developments are motivating the need to consider a fresh approach to mining education and training at all levels for industry. A growing diversity and complexity of professional responsibilities is extending the mining engineerÆs broadly based skill set and reinforcing the need to play a central role within increasingly interdisciplinary teams. On the other hand, the imminent new technologies that will transform the mining process are prompting the assumption that more focused and specialised skill sets will be needed. A way forward is suggested that would first define a blueprint for the future mine, as an attempt to characterise the systems architecture, processes and organisation of the next generation mine. This can be the basis for assessing the nature of the workforce and distribution of responsibilities, from which can be inferred the skills and training requirements. In the context of the mining engineer, the paper explores how understanding such future requirements will enable more proactive development of a strategy for educational development. The paper then concludes by considering issues and lessons learned from some recent mining educational development initiatives underway in Australia and Canada that are shaping significant change.

Jan 1, 2008