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By L. Bratek, K. Jaworek, M. Czaplicka

Methods for arsenic compound removal from aqueous solutions include processes such as: coagulation, adsorption, membrane techniques, electrochemical and biotechnology techniques. Advanced oxidation using both UV radiation and strong oxidizing agents such as ozone and hydrogen peroxide may also decompose these compounds. It is known that effluents from metallurgical processes contain inorganic arsenic compounds in addition to the organic compounds such as: dimethylarsinic acid and phenylarsonic acid. This paper presents the conditions that lead to the formation of deposits containing mainly arsenic, such as pH, the wavelength of the radiation and the type of oxidant, for this type of effluent.

Jan 1, 2014

By Robert B. Parsons

"While it might seem like heresy to suggest that ""taxation"" can be a source of financing, never the less some generous tax rules can considerably enhance the tax savings pertaining to a particular expenditure or project. A basic tax knowledge, and careful tax planning, can optimize government participation in a project. INTRODUCTIONIn trying to identify sources of financing for a project, ""government"" as a source of funding is normally thought of in terms of government grants, loan guarantees, interest rate buy downs, property tax waivers, hydro subsidies, and so on. Generally, such concessions are somewhat difficult to obtain, especially in the current period of apparent fiscal restraint. One source of government funding which should not be overlooked is the income tax regime, and, at the provincial level, the various provincial mining tax regimes.While the taxpayer would not normally view a tax system as a potential source of government financing, nevertheless various federal and provincial rules applicable to the mining industry can offer attractive tax deductions - and tax savings - with respect to particular expenditures. In fact, it is not unusual for a civil servant to refer to a tax deduction as a tax ""subsidy"". For example, in the right circumstances, the cost of a smelter expansion in New Brunswick would cost the operator only 31 cents on the dollar, with the federal and provincial governments paying for the other 69 cents by foregoing tax revenues (Table I). In a sense, such tax savings could be compared to a government grant equal to 69% of project costs. Of course, not every project expenditure will generate that degree of government funding. The fact of the matter is that the percentages of tax savings attached to different expenditures cover a wide range, depending on a complex mix of factors. The point to understand is that the tax rules can offer some valuable savings, even after tax reform, and that a basic knowledge of the tax rules can yield some fruitful rewards."

Jan 1, 1989

"The Val d'Or Division now comprises the Lucien C. Beliveau Mine and Concentrator (formerly the Pascalis, described below) and the Chimo Mine. Cambior acquired an initial 50% interest in the Chimo Mine in May 1989 and the remaining 50% in April 1990. Cambior's share of 1989 production was 2121 ounces; the company expects to net 23 750 ounces from Chimo in 1990. Pascalis MineUPDATERenamed the Lucien C. Beliveau Mine at its official inauguration in September 1989, the mine is exceeding forecasts, producing over 11 500 ounces of gold in the first half of 1990. Cambior expects 1990 production to total 34 000 ounces.IntroductionThe Pascalis Mine is located 16 miles east o f Val d'Or, Quebec, and is accessible by a three mile gravel road off highway 117 (Fig. I).The property is wholly owned by Cambior.The Pascalis gold deposit consists o f a sub-vertical diorite dyke 1000 ft long by 30 ft wide containing quartz and tourmaline veins with inclusions of pyrite and native gold . Three vein systems ca n be seen in the deposit , the most important being tensile veins oriented at a right angle to the direction of the dyke and inclined at 40 degrees. These overlapping veins vary in thickness from 4 in. to 40 in. and occur at intervals of six to ten ft. The deposit is, therefore, very difficult to evaluate; a complete evaluation would require drifts over the whole width of the dyke combined with relatively short drill holes (Fig . 2)."

Jan 1, 1990

By B. Voyzelle

The deterioration of highway and bridge infrastructure has received considerable attention in recent years because of the billions of dollars needed for repair and rehabilitation. A major factor contributing to this problem is the corrosion of steel reinforcement. Reinforcing steels with good corrosion resistance and relatively low price are therefore essential for maintenance, cost reduction and service-life extension of the steel-reinforced structures. This article describes the development of low-alloying steels that offers good corrosion resistance with reasonably low cost. Topics include steel microstructures, mechanical properties, corrosion performance, industrial applications and economic aspects.

Jan 1, 2005

By S. Nakamura, M. Takaoka, Y. Mizuno, T. Kusakabe

"Mercury is produced as a byproduct from gold mines and, historically, has been transferred to recyclers and used for various industrial processes and products. However, under the Minamata Convention on Mercury, adopted in 2013,the intentional use of mercury in processes or products will be minimized in the world. Surplus elemental mercury should be treated as a hazardous waste and consequently, should be converted to a more stable chemical form for long-term storage or permanent disposal. A stabilization method has been developed to react mercury and sulfur using a planetary ball mill. The planetary ball mill can produce high-energy conditions and enable samples to react within a short period of time. A series of tests has been conducted to confirm that mercury sulfide can be produced using a bench scale machine with 2400 mL pot. Under a suitable experimental condition with 25 mm ball diameter, 30%of ball filling rate and 1.05 of molar ratio of S/Hg, a powdered mercury sulfide product was successfully obtained in 60 minutes. The leach ability and atmospheric emission from the product was extremely low. This stabilization method would contribute to an environmentally sound mercury management strategy for the gold industry.INTRODUCTIONDue to its unique physical and chemical properties, mercury has numerous applications, including in industry and medicine. However, mercury and its compounds are highly toxic. For example, in Japan, methyl mercury in waste water caused Minamata disease in the 1950s, which affected large numbers of people (Minamata Disease Municipal Museum, 2001). In recent years, environmental pollution caused by emissions and releases of mercury into the atmosphere, waterbody and land by various emission sources such as coal fire plants, artisanal and small-scale gold mining (ASGM), non-ferrous metal industries, waste incinerations etc. has also become a significant problem. To protect human health and the environment from anthropogenic emissions and releases of mercury and its compounds, the Minamata Convention on Mercury was adopted in 2013(UNEP, 2013)Because ground gold ore typically contains mercury at 0 to 100 ppm, mercury is often produced as a byproduct from gold mines (UNEP, 2016). In gold mining operations, mercury can be released from the ore by roasting or by leaching in cyanide solutions and recovery onto activated carbon. According to Yanget al. (2016), 85.1%of mercury in a concentrate was vaporized during a roasting process. Both processes finally discharge elemental mercury as a byproduct. In the USA, more than 100 ton of mercury was discharged from large-scale and industrial gold mining (Miller, 2004)."

Jan 1, 2017

By H. Lachmund, R. Bruckhaus

At Dillinger Hüttenwerke/Germany steel production of grades for linepipe applications especially for sour service has a long tradition. The BOF process after replacement of the vessels is optimized by a newly developed lime addition model and variations in lance tip geometry. Equipped with three state-of-the-art VOD tank degassers metallurgical requirements of lowest contents of e. g. sulphur, nitrogen and hydrogen can be achieved. Three continuous casting machines of vertical bending type with solid core even improve already high levels of cleanliness. The vertical part corresponds to the metallurgical length of 12 to 15 m and therefore assures a maximum of cleanliness after solidification before bending. Slab thickness up to 400 mm can be produced with model controlled dynamic soft reduction. The accurate alignments of the casters assure minimized segregation and microporosity. Surface and internal cracks can be avoided by special cooling, bending and straightening strategies.

Jan 1, 2005

By Derek H. C. Wilton

"The Nain Province (NP) of northern Labrador is a >600 km long by =100 km wide Archean craton that has undergone relatively little mineral exploration until economically signifcant concentrations of orthomagmatic nickel sulphide were discovered by Diamond Fields Resources (DFR) at Voisey’s Bay. Due to the great time span between crust formation andfnal intrusive activity (ca. 3.9 Ga to 1.27 Ga),there were, however, numerous metallogenic events within the NP.The NP was intruded by the ca. 1.3 Ga to1.2 Ga Nain Plutonic Suite (NPS) composite anorthosite-granite complex. The NPS dividesthe NP into the southern Hopedale Block (90 km by 150 km) and the northern SaglekBlock (375 km long by =50 km wide). These two blocks appear to represent two distinct Archean cratonic nuclei, each with its own distinct metallogenic history. The NPS is a coalesced assemblage of composite intrusions which include anorthosite, troctolite, norite, gabbro and granite.The Hopedale Block contains the Hunt River and Florence Lake greenstone belts, and the Weekes Amphibolite which represents remnantsf the older Hunt River greenstone belt. Geologically, these belts have some potential to host komatiitic Kambalda-style nickel, volcanogenic massive sulphide (VMS) and meso -thermal lode gold mineralization. The unconformity between Paleoproterozoic cover sequences and the trondhjemite-tonalite-granodiorite (TTG)suite which engulfed the greenstones was the locus for lead-zinc-bearing quartz-carbonate veins. Minor fracture-hosted uraninite showings are also present in the TTG.The Saglek Block is a high-grade gneissterrane with deformed Archean supracrustal sequences but no greenstone belts. Within the gneiss are variably-sized enclaves that range in composition from anorthositic to ultramafic; some of these latter xenoliths contain abun-dant fuchsite. There are also three small anorthositic to ultramafic meta-igneous complexes present in the gneiss near Okak Bay.Some Archean meta sedimentary and maficgneiss supracrustal sequences contain iron-oxide and sulphide members. The sulphide-bearing Tasiuyak parag neiss defines the cra-tonic suture between the NP and Churchill(Rae) Province. Along the cratonic suture between the NP and Churchill Province from Ramah Bay north are remnants of the Archean(or Paleoproterozoic) Hutton Anortho site Suite. Ultramafc layers within the suite contain chromite and elevated Ni values.Three ca. 2.0 Ga supracrustal sequenceswere deposited in small fault-bounded basins within the NP. The Snyder Group contains pyrrhotitiferous massive sulphide horizons. TheMugford Group contains SEDEX-like massive sulphide blocks in a debris fow and ultramafic sills with unusual PGE concentrations; alaskitic granite cutting basement gneiss to the group contains stockwork-like pyritiferous quartz veins. The Ramah Group contains numerous MVT-style zinc-lead sulphide occurrences.The Reid Brook Intrusion of the NPS contains enormous and high-grade nickel-copper-cobalt massive sulphide bodies at the Voisey’s Bay deposit. Exploration in the northern portions of the NPS in 1995 has indicated the presence of other potentially economic nickel sulphide horizons."

Jan 1, 1996

By W. H. Miller

Introduction In this paper we have endeavoured to present a general description of the electrical applications underground at Copper Mountain, including types of equipment used, problems encountered, and methods by which they were overcome. No attempt has been made to outline in detail the wiring of various circuits. Until recent years, the main use of electrical energy underground at Copper Mountain consisted of direct current for locomotives, trolley systems, .and signal and communication circuits. The prohibitive cost of equipment and distribution systems prevented any extensive use of a.c. beyond that commonly used for essential lighting purposes. However, in 1943 the shortage of manpower and the increased cost of labour and supplies necessitated a general mechanization programme.

Jan 1, 1951

By H. Bouzahzah

Sulfidic tailings, subjected to atmospheric water and oxygen action, can generate acid mine drainage (AMD); which is the most important environmental problem facing the mining industry. AMD generating potential can be assessed by the static tests which consist of a screening method where the neutralization potential (NP) and the acid-generating potential (AP) of a given rock sample are determined. The AP and NP are determined separately in the different static test existing procedures which can be divided into two distinct classes: chemical and the mineralogical methods. For some chemical method, the AP is calculated on the basis of total sulfide sulfur content in the sample which may overestimate its AP if significant quantities of non-sulfide sulfur species are present (e.g. organic S in coals, some sulfate as gypsum, barite, etc.). However, the mineralogical method evaluates the AP by the sum of the individual sulfides participation on acid generation based on their concentration within the sample and can be more accurate than the chemical method. For AP calculation, the Paktunc (1999a) mineralogical static test takes into consideration all sulfide minerals occurring in the sample. However, it does not take into account the rates of acidity production of these sulfides submitted to weathering conditions. So, the present study focusses on the modification of Paktunc AP calculation by considering the acidity production rates of these minerals. To reach this objective, five base-metal sulfides (pyrite as reference, chalcopyrite, sphalerite, arsenopyrite, galena), diluted within quartz (25?75 wt.%) simulating mill tailings were subjected to a kinetic test to evaluate their AP. The results show that all the studied sulfides minerals generate acidity at different rates, so the Paktunc?s equation for AP calculation has been adapted accordingly.

Aug 1, 2013

By Floyd B. Bowen

Pumping methods are used, almost exclusively, to transport materials in the mining, beneficiation and chemical processing of phosphate rock in the Florida phosphate pebble field. Matrix pumping systems capable of pumping 15,000 g.p.m., transporting 15,000 long tons (dry) per hour, are now in use. They utilize 16-by 48 Yz -in. pumps, driven by 1.250-h.p. motors, discharging into pipelines 20 inches .in diameter .and sometimes several miles in length. As an average, it is necessary to pump 3 tons of matrix to the beneficiation plants, and to dispose of 2 tons of sand tailings and clay as waste, in order to produce 1 ton of shipping-grade rock. The washers and flotation plants, where the clay and phosphate and silica particles are separated, require the movement of large volumes of slurries with densities ranging from 2-3 per cent to 45 per cent solids, by weight. Extensive waste disposal systems require the pumping of dilute clay slurries in quantities of up to 50,000 g.p.m.,

Jan 1, 1963

By C. A. Jeffrey, K. Pearson

Abstract - The Croft diorite in central England belongs to a suite of Caledonian igneous rocks collectively known as the South Leicestershire diorite complex. Although the intrusions occupy separate outcrops, they are linked at depth to form a single pluton, buried beneath a cover of Triassic sediments (Le Bas, 1972; 1982, Allsop and Arthur, 1983). Both the Caledonian diorites and the overlying sub-Triassic unconformity have been affected by a complex history of alteration and mineralization which can be subdivided into four stages: (1) deuteric effects, caused by the release of volatiles during magmatic cooling; (2) albitization through sodic enrichment; (3) formation of lowtemperature laumontite, analcime and calcite veins with associated wall-rock alteration to prehnite and pumpellyite; and (4) sub-Triassic unconformity-hosted base metal, manganese and palygorskite mineralization. Zeolite mineralization occured some 200 Ma later than the intrusion itself, during post-Triassic times, as indicated by the presence of a single vein of laumontite and microcrystalline calcite which cross-cuts the sub-Triassic unconformity surface and enters the overlying Triassic sediments. Evidence from fluid inclusion work indicates that two fluids were involved in the deposition of the zeolite veins. One fluid was initially of relatively high temperature (~100°C to 320°C) and low salinity (~0.2 to 5.9 wt% NaCl equiv.), and was probably meteoric in origin, whereas the other was of relatively low temperature (~41°C to 165°C) and high salinity (~0.4 to 16.72 wt% NaCl equiv.), and is interpreted to represent a basinal brine. During Triassic rifting, thinning and fracturing of the crust, with the possible rise of associated magmas (Halliday and Mitchell, 1984), could have increased permeability and heat flow, initiating the circulation of hydrothermal fluids. Triassic unconformity-hosted base-metal mineralization in Central England is similar to other Triassic-Jurassic mineralization in Europe (Mitchell and Halliday, 1976).

Jan 1, 1997

By C. A. Jeffrey, K. Pearson

The Croft diorite in central England belongs to a suite of Caledonian igneous rocks collectively known as the South Leicestershire diorite complex. Although the intrusions occupy separate outcrops, they are linked at depth to form a single pluton, buried beneath a cover of Triassic sediments (Le Bas, 1972; 1982, Allsop and Arthur, 1983). Both the Caledonian diorites and the over-lying sub-Triassic unconformity have been affected by a complex history of alteration and mineralization which can be subdivided into four stages: (1) deuteric effects, caused by the release ofvolatiles during magmatic cooling; (2) albitization through sodic enrichment; (3) formation of low-temperature laumontite, analcime and calcite veins with associated wall-rock alteration to prehniteand pumpellyite; and (4) sub-Triassic unconformity-hosted base metal, manganese and palygorskite mineralization. Zeolite mineralization occured some 200 Ma later than the intrusion itself, duringpost-Triassic times, as indicated by the presence of a single vein of laumontite and microcrystallinecalcite which cross-cuts the sub-Triassic unconformity surface and enters the overlying Triassic sediments. Evidence from ?uid inclusion work indicates that two ?uids were involved in the deposition of the zeolite veins. One ?uid was initially of relatively high temperature (~100°C to 320°C) and lowsalinity (~0.2 to 5.9 wt% NaCl equiv.), and was probably meteoric in origin, whereas the other wasof relatively low temperature (~41°C to 165°C) and high salinity (~0.4 to 16.72 wt% NaCl equiv.),and is interpreted to represent a basinal brine. During Triassic rifting, thinning and fracturing of the crust, with the possible rise of associated magmas (Halliday and Mitchell, 1984), could have increased permeability and heat ?ow, initiating the circulation of hydrothermal ?uids. Triassic unconformity-hosted base-metal mineralization in Central England is similar to other Triassic-Juras-sic mineralization in Europe (Mitchell and Halliday, 1976).

Jan 1, 1997

By P. Nos, L. Kolbeinsen, M. W. Kennedy, A. Filzwieser, R. T. Jones, A. MacRae

Modern furnace designs often incorporate extensive use of cooled elements to achieve long campaign lives at high operating intensities. However, contact between water and high temperature fluids can result in powerful Boiling Liquid Expanding Vapour Explosions (BLEVEs). Therefore cooling such elements with water carries inherent risks when used under slag and particularly below molten metal or matte. Alternative cooling media exist that can reduce or eliminate the risk of BLEVEs. These media are analysed and discussed in the context of deeply cooled furnace elements. Important factors in selecting alternative coolants are explored including: critical heat flux, thermal limits, toxicity, flammability, unit cost, etc. Key cooling system design criteria are reviewed in the context of both traditional and alternative coolants. Results of Computational Fluid Dynamics are presented for an example tap-block cooler design using a number of selected coolants. Research needs to advance the safe use of alternative coolants are presented.

Jan 1, 2015

By C. M. Diaz, P. J. Mackey

Since its inception, in 1987, the Copper-Cobre series of conferences has established itself as the prime world forum for discussing advances in copper process metallurgy, in particular copper sulfide smelting, copper recovery by leaching and electrowinning and copper electrorefining. All copper producing countries have actively participated in the pyrometallurgy symposia held in the framework of these conferences. In 1999 and 2003, the close to 100 pyrometallurgy papers that were presented had to be accommodated in two volumes. In the present paper, the authors firstly provide a brief historical sketch of the Copper-Cobre conferences and then focus on providing a retrospective look at the dramatic changes that have taken place in copper smelting in the last few decades, primarily as discussed in the Copper-Cobre and precursor conferences pyrometallurgy proceedings. Topics include: the development of autogenous, increasingly more intensive, environmentally sound and energy efficient smelting processes; significant improvements in Peirce-Smith converting practice and at the same time the commercialization of alternative continuous converting routes; the consequent expansion and modernization of smelters; the increasing compliance with strict government environmental regulations in most copper producing regions of the world; the realignment of the copper smelting industry throughout the world; and trends in copper smelting R&D. A look at the future closes these reflections on the contribution of the Copper-Cobre conferences to the advancement of copper smelting technology.

Jan 1, 2007

By M. Kreuh

Crystalline Mg(OH)Cl and amorphous Mg2(OH)3C1 were successfully isolated from a hydrolyzed molten salt electrolyte sample in this work, It was found that the chemical form and crystallinity of the hydroxylchloride were controlled by the cooling rate of the molten sample when it was taken. Crystalline Mg(OH)Cl could only be obtained by cooling the molten electrolyte sample at a rate not faster than 0.6 °C/min, Upon more rapid cooling, the hydroxylchloride species precipitated as Mg2(OH)3Cl, The behavior of these solid hydroxylchlorides when contacted with fresh and non-hydrolyzed molten electrolyte at 550°C was also examined, It was found that the Mg(OH)Cl rapidly dissolved in the hot electrolyte and did not decompose into MgO at that temperature as would be expected from the literature, The dissolution rate of solid Mg2(OH)3Cl was found to be so slow by comparison that it resulted in the complete decomposition into MgO which thereafter was incorporated into the electrolyte as a suspended solid phase rather than dissolution.

Jan 1, 2004

By John Ramsay, Frederick A. Edwards, J. Eric Belford, Clarence V. Amyotte

"DEVELOPMENT of the underground mine is carried out from a main ramp driven from surface to the 800 and 1200 levels and from a shaft sunk to 3050 ft. Sub-levels at approximately 100-ft vertical intervals, starting 300 ft above the 800 level, were collared from the ramp as it advanced and a considerable amount of development work was pursued. The lateral and ramp work provided an opportunity to train drift crews, test equipment and methods, assess ground conditions and advance the initial stope development. The development of an exhaust ventilation raise system closely followed the extension of the level development to the south end of the orebody (Fig. 26) . On completion of the shaft, temporary lip pockets were installed at the shaft stations on the 800, 12.00, 1600, 2000 and 2400 levels. The permanent loading pocket had been installed on the 2860 level as part of the shaft-sinking contract and the level had been connected to the 2800-level station by a small muck transfer raise. Development of the 2800-level area was given top priority at this stage. This included a 1000-ft cross-cut to the crusher location, the crusher excavation, storage bins, conveyor ways and a ramp to connect the 2800 level to the loading pocket, the rope changing station and the shaft sump. The development and installation of the rock handling system between the 2400 level and the shaft bottom was contracted to Macisaac Mining and Tunnelling Company, of Sudbury, Ontario."

Jan 1, 1974

By C. G. McLaughlan

The Noranda concentrator was placed in operation in October, 1928, and the object of this paper is to outline operations during the twelve months which have elapsed since that time. The ores milled are massive sulphides carrying copper and gold, and, in certain cases, zinc. These ores have a specific gravity of about 3.8. The average assay of the copper-gold ore so far treated has been 2.0 - 3.5 percent Cu; 0.10 - 0.20 oz. Au; 40 - 51 percent Fe; and 6 - 15 percent SiO2. In this ore the copper occurs almost entirely as chalcopyrite, and the iron which is not combined with the copper is present mainly as pyrite and pyrrhotite. ?some iron is also combined with the silica, the ratio being about 1 to 4, and a small percentage is present as magnetite. The occurrence of the gold has been shown by microscopic work carried out by Prof. L. C. Graton, of Harvard University, to be very variable. Some of it is free, and is included within the base-metal sulphides or occurs at their boundaries. A similar distribution also holds for a portion of the gold which is combined as a telluride. Little is so far known of the occurrence of the silver other than that some of it may be combined with the gold in the telluride, petzite. The copper-zinc ore contains up to 6 percent copper, and has a very variable zinc content. The copper in such ore is present as chalcopyrite, and the zinc as sphalerite. In starting the mill we had three conditions to face; the first of these was climatic, the second was the lack of skilled flotation operators, and the third was the ore itself." The last of these three proved much more difficult to contend with than the other two combined.

Jan 1, 1930

By Jack Young

U. S. Steel Canada Inc.’s Lake Erie Works is the last green field integrated plant to be built in North America. The plant was designed using the best available environmental technology to develop an environmentally friendly production facility. A summary of the technology and measures used in the construction of the plant are summarized in this paper.

Jan 1, 2015

By Louise Grondin

Laronde Mine has been working for a number of years to identify substances that could contribute to process water toxicity and to find an effective way of removing these contaminants from the water. Initial studies have identified ammonia, nitrite, cyanide, thiocyanate, cyanate, dissolved organic carbon, copper and zinc as potential toxicants. Bench-scale tests were carried out with Lakefield Research to find a water treatment process that could effectively remove the suspected toxicants. Nine treatment processes were evaluated: 1) granular activated carbon (GAC) filtration followed by zeolite, 2) zeolite filtration followed by GAC filtration, 3) aeration followed by GAC filtration, 4) multi-stage GAC filtration, 5) chlorination followed by dechlorination, 6) addition of clay based polymer, 7) treatment with peroxide and ultra-violet light, 8) bulk addition of GAC and zeolite powder, 9) treatment with bacteria. This article presents a summary of the test results and of the problems associated with the evaluation of technologies for the treatment of toxicity.

Nov 1, 2002

By M. M. Williams

ALBERTA has been generously endowed with oil, natural gas, coal and water power, thus giving power producers a wide choice in the type of plant and fuel which can be used. Therefore, with such a variety of energy sources to choose from, why was coal selected as the primary fuel at Calgary Power's Wabamun steam plant? This part of the paper will cover the circumstances that led the Company to decide in favour of coal. The second part, to be presented by C. F. Doerr, will describe how the Wabamun coal mine has been developed to supply the large fuel requirements of the power plant. Before considering the Wabamun plant, we require a general under-standing of? the Company's electric system and load. Power is fed into a 5,100-mile high-voltage transmission grid from eleven hydroelectric plants and from the Wabamun steam electric plant. These plants have a combined generating capacity of 820,000 horse-power. Of this total, the hydro

Jan 1, 1963