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By H. Rosenberg

Haldor Topsoe A/S has developed its WSA technology to meet the demand in the market for a simple and reliable process that converts sulphurous emissions from off-gasses into high-grade sulphuric acid. With more than 50 references in 25 countries, the WSA technology has proven its ability to generate acid at 98% concentration, efficiently and economically. The wet gas sulphuric acid (WSA) technology treats the furnace off-gas directly from upstream gas cleaning plants. No further drying is required, since the humidity present in the off-gas is used to hydrate the SO3generated in the converter and produce sulphuric acid. The heat generated during the oxidation, hydration and condensation processes is principally reused in the process to preheat the off-gas to the required temperature level, and also to generate high pressure superheated steam for process use. This advantage of steam production, coupled with lower water and power consumption requirements, is particularly important in the African production environment. Having fewer process components than conventional acid plants, the WSA technology is a simple and compact operation, which makes it easier to retrofit into an existing smelter plant. Further, the WSA technology simultaneously offers the possibility to treat multiple gas streams arising within the production facility due to superior flexibility in terms of SO2concentration and turndown ratio.

Jan 1, 2006

By Ole Rud Bendixen

Topsoe has developed a Wet gas Sulphuric Acid (WSA) process which effectively recovers SO2 in off-gases from non-ferrous smelters and roosters. The product is concentrated sulphuric acid of typically more than 96 wt% irrespective of SO, concentration in off-gas. The process does not generate any waste products or waste water and does not use any absorbents or other chemicals. In the process, up to 99.3% of the SO2 is converted catalytically into SO3, which reacts with water in the gas, hereby forming gaseous sulphuric acid. The acid is condensed in a WSA condenser of proprietary design. Excellent heat economy and practically no sensitivity to the water balance mean that no extra sulphur burning is required at any S02 concentration, The process is especially well suited for treating off-gases where the SO2 content is lower than approx. 5-6%, and it is a good alternative to a complete renovation of a smelter. However, also off-gas from flash smelter may be treated. The process has found good use in both molybdenum and lead roosters. An example from a molybdenum roaster in Chile shows that 97-98wt% acid is produced from a 2.3 % S02 gas. This plant is situated in the outskirts of Santiago and represented a major local source of SO2. The plan was started in May 1993.

Jan 1, 1996

By A Grigg, L Hackett

Alcoa operates two bauxite mines at Huntly and Willowdale, located within the jarrah forest south-east of Perth in Western Australia. Ore reserves are shallow but extensive, and mining pits averaging around 20 ha in size are distributed across a mining region in a mosaic pattern, linked to a centrally-located crusher by a radiating network of haulroads. A mining or crusher region is defined partly in terms of economic haul distances, and new regions are opened once the current regions’ reserves have been mined. Since commencing in 1973, the Huntly mine has constructed and progressively closed three previous mining regions and is presently in a transition from the fourth and current region of McCoy to the new region of Myara. At present rates of production, approximately 450 ha is cleared, mined and rehabilitated each year.The value of topsoil in returning a diverse mix of native jarrah forest plant species and supplying nutrients, organic matter and soil biota to rehabilitated areas has long been recognised. Managing the topsoil resource is therefore a critical element in the success of rehabilitation outcomes, but the distribution and dynamic nature of mining operations pose significant planning and logistical challenges. The regionalised approach to mining at Huntly also presents a range of issues for what are, in effect, soil management plans for episodic mine closure. The nature of mining and rehabilitation operations are described, together with the planning processes that Alcoa follows to quantify, track and report on soil movement. A case study of the Huntly mine demonstrates that an integrated operational and life-of-mine planning process is essential for successful and cost-effective mine rehabilitation.CITATION:Hackett, L and Grigg, A, 2014. Topsoil management for long-term mine operation and closure – a case study from Alcoa's bauxite mining operations in south-west Australia, in Proceedings Life-of-Mine 2014 , pp 609–614 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Jr. Stokowski

Topsoil for revegetation projects is in demand in many urban areas. In this case history, a large aggregate producer manufactured a topsoil from three waste materials. The topsoil was produced in a 200,000 m2 (50-acre) abandoned gravel pit that still had additional gravel under 10 m (30 ft) of overburden uneconomic to strip directly. The topsoil was produced by rotary mixing of sludge, overburden, and a lime admixture; solar drying; and stripping and stockpiling of the product. A major problem was an increase of topsoil drying times for stripping from 40 to over 100 hours when it was rewet by storms. The problem was solved by a research project that evaluated over 50 formulations and over 20 waste materials. . The final formula dried in 15 hours and contained 3-parts sandy mine spoil, 1-part sewage sludge, and 2 % spent-bed, a granular quick-lime produced during power-plant flue-gas desulfurization.

Jan 1, 1988

By F. M. Sandoval, R. E. Ries, J. F. Power

Returning the original soil material to the surface of smoothed mine spoils is a practical means of restoring agricultural productivity. Research has established that high-sodium spoils in North Dakota: (1) must be covered with about 70 cm of soil material to achieve maximum production; (2) top-soil must be segregated and spread separately from subsoil; (3) potential production depends on the quality of the soil material returned; and (4) erosion and upward salt movement must be controlled for sustained production. Erosion is best controlled by reducing final grades as much as possible during the smoothing process followed by prompt establishment of vegetation.

Jan 1, 1980

By F. M. Sandoval, R. E. Ries, J. F. Power

Returning the original soil material to the surface of smoothed mine spoils is a practical means of restoring agricultural productivity. Research has established that high-sodium spoils in North Dakota: (1) must be covered with about 70 cm of soil material to achieve maximum production; (2) top-soil must be segregated and spread separately from subsoil; (3) potential production depends on the quality of the soil material returned; and (4) erosion and upward salt movement must be controlled for sustained production. Erosion is best controlled by reducing final grades as much as possible during the smoothing process followed by prompt establishment of vegetation.

Jan 12, 1979

By J. F. Power

Returning the original soil material to the surface of smoothed mine spoils is n practical means of restoring agricultural productivity. Research has established that high-sodium spoils in North Dakota (a) must be covered with about 70 cm of soil material to achieve maximum production; (b) topsoil must be segregated and spread separately from subsoil; (c) potential production depends on the quality of the soil material returned; and (d) erosion and upward salt movement must be controlled for sustained production. Erosion is best controlled by reducing final grades as much as possible during the smoothing process followed by prompt establishment of vegetation. Almost half the nation's cool reserves are in the Northern Great Plains underlying several million hectares of agricultural land. Social pressures to return mined land to agriculture or other productive uses have resulted in recent enactment of state and federal legislation, which is intended to restore productivity to disturbed areas. All such legislation relating to the Northern Great Plains has stipulated that useable soil material be saved and returned to mined land after spoils are smoothed. This requirement immediately raises questions as to how much soil material is needed, what criteria are important in defining useable soil material, how is the soil material to be handled in the earth-moving operations involved, and how can replaced soil material be maintained and revegetation. Scientists at the USDA Northern Great Plains Research Center at Mandan, North Dakota have conducted research on the reclamation of disturbed lands since 1970. Initially this research was designed to identify and characterize those physical and chemical properties of spoils that are most restrictive to plant growth (1). Basically, they found that any properties of spoils that reduced the efficiency of storage and utilization of the limited precipitation received adversely affected plant growth. Thus, in the Northern Plains, revegetation of mined land was found to depend upon the management of factors affecting the availability of water to plants - the same as on unmined land. After the major problems in revegetation were identified, technologies were developed to circumvent the effects of the growth-limiting factors (2). Basically two approaches were identified by which plant growth-restricting properties of spoils could be corrected: (a) various amendments (gypsum, sulfur, Fertilizers, mulches, calcium chloride, etc.) could be applied to spoils to improve their ability to conserve precipitation and provide water for plant growth; or (b) undesirable spoils could be covered with suitable soil materials to reduce or alleviate adverse effects. The latter approach appeared to be more feasible in most instances And is the approach specified in current legislation. The remainder of this paper discusses research on the use of roil materials returned to spoils and summarizes the information obtained.

Jan 1, 1978

From the cold Pacific waters in June rolls a blanket of white clouds that tucks up around the mountains at around 8000 or 9000 ft. This is the way it happens in southern Peru and so the mining operations and daily living at Toquepala have an ethereal quality not often encountered. Besides looking down on the clouds from the brightly sunlit mountain tops, one can discern the trace of a different era in the brown barren mountain slopes. This trace is like a delicate net laid over the surface of the earth-a criss-crossing of innumerable trails that are so omnipresent, yet faint, that the local people have long since ceased to notice them. It is difficult at first to ask about them because no one understands what you are talking about. It finally comes out though, that the markings are indeed trails, but fossil trails made by animals in times when they were in abundance in a countryside that was green in some bygone century. In a way Toquepala is still pristine, it is the way the engineers planned it-from the ground up. There are no additions or expansions- those tackings-on that spoil the symmetry of design while increasing the profit. This does not deny that annual production has gone up over the years. Daily mill throughput has been increased from 30,000 to 42,000 tpd. Initial design of the concentrator was for 30,000 tpd but in 1964-65 milling capacity was increased to 36,000 tpd at a cost of $3 million.

Jan 11, 1969

By Igor Gonzales G.

Southern Peru Copper Corporation (SPCC) has recently completed the construction of copper leaching, solvent extraction, and electrowinning facilities at their Toquepala and Cuajone plants in Southern Peru. Much of the ore for these new operations is the result of the existing mining operations that have been in existence as early as 1959. At Toquepala, pre-conditioning and bacterial dump leaching of the sulfide ore that was too low in copper content to be processed through the copper concentrator began in 1987. The Cuajone heap leach operation is treating copper oxide ore that has been stockpiled since the Cuajone concentrator began operation in 1976. The pregnant leach solutions from the dump leaching at Toquepala and the permanent pad heap at Cuajone are combined into one plant feed solution. Adjacent to the large dumps at Toquepala, a solvent extraction and electrowinning facility has been constructed. The electrowinning facility has a planned annual production rate of35,000 metric tons per year Grade A cathode copper. Initial production of the cathode copper began in November 1995.

Jan 1, 1996

By V. I. Lakshmanan, Chris Dodson

Refractory gold ores or concentrates are pretreated in general by physical, chemical and biological oxidative pretreatment processes prior to cyanidation for the economic recovery of gold. The thermal treatment processes generally include fluid bed pro­cessing(!>, chemical with pressure<') or atmospheric (Caro's< ·'>, 3 Nitrox1')) pretreatment leaching and physical with ultrafine grinding!"). Roasting and aqueous pressure oxidation pretreat­ment methods have several commercial applications (Homestake, Barrick) and biological oxidation methods have recently found industrial applications in Africa. The roast pretreatment methods to treat refractory sulphide ores or concentrates transform iron sulphides generally to a porous iron oxide matrix assisting the lixiviant cyanide to effectively diffuse the calcine for cyanidation and hence with improved gold recovery. Jha and Kramer<') made an extensive review of roasting chemistty and practice to tt·eat refract01y gold ores. Industrially two stage pretreatment roasting is generally employed. During the first stage roasting is carried out under oxygen deficiency conditions to provide a low arsenic calcine, mainly magnetite and in the second stage magnetite is trans­formed to haematite under oxidizing conditions.

Jan 1, 1998

By L. W. Helle

This paper summarizes the investigations carried out into a defect involving the corners of billets rolled from continuously cast blooms, which broke open during the rolling process. As it was believed that the defect must be connected with the formation of subcutaneous blowholes in the bloom, the investigations were directed towards an understanding of the roles of the three gases involved in the process. In an extensive trial programme, samples were taken from the heat at all stages of processing, as well as from all the raw materials and alloys. The main sources of nitrogen were found to be re blows, pick-up from the alloys added to the ladle (especially graphite), and open-stream casting. The major source of hydrogen was moisture in the alloys, especially high-carbon ferromanganese and silicomanganese. Further, it was established that the moisture content of the alloys is closely related to the appearance of the defect in steels with a carbon content of less than 0,20 per cent; 72 per cent of all the defects were present in this type of steel. Most of the remaining defects were found in steels with a carbon content of more than 0,60 per cent, where the nitrogen content was substantially higher than in the lower-carbon steels. It is suggested that the defect arises from the combined effect of oxygen. nitrogen, and hydrogen. Its occurrence in low- and high-carbon steels is triggered by the formation of subcutaneous blowholes when the critical oxygen level for carbon monoxide blowholes is lowered by the presence of excessive amounts of hydrogen and nitrogen respectively.

Jan 1, 1984

Toronto 2013 Proceedings

May 1, 2013

Jan 1, 1908

By W. R. Ingalls

ThE following chronology presents the history of lead-mining in the United States in a brief form and is a useful reference in connection with the statistics of production: 1621.. Lead was mined and smelted near Falling Creek, Va., to supply the local demand for bullets and shot. This was the first mining and .smelting of lead in what is now the United States. 1632. In a report made on the minerals of New England, lead-ore is mentioned. (Bishop, I., 470.) 1650. Supposed beginning of mining by Jesuits in Pima county, Ariz. 1651. Grant of lead-mine at Middletown, Conn., to Gov. John Winthrop. 1682. Lead-ore supposed to have been discovered in Wisconsin by Nicholas Perrot. (K. D. Irving, Mineral Resources of Wisconsin, Trans., viii., 498.) 1700 Discovery of lead in Missouri by Penicaut, one of Le Sueur&apos;s party. Tile same expedition discovered lead near the southern boundary of Wisconsin in August of the same year. 1712. Grant by Louis XIV. of the Crozat patents, with special privileges respecting the discovery and operation of mines in the then territory of Louisiana. Little or no mining was done under this patent until about 1720. 1717. Transfer of Crozat patents to the Mississippi Co., promoted by John Law, which prepared for active mining. 1719. First attempt to mine and smelt lead in Missouri, made by Sieur de Lochon, in behalf of the Mississippi Co., near Meramec river. Results unsuccessful.

Jan 1, 1908

By Edward W. Parker

Note.—The material from which this paper has been prepared was collected tor the U. S. Geological Suvey Bulletin, No. 316, Contributions to Economic Geology, 1906, and appears also, though in somewhat more extended form without illustrations, in that publication. Although the briquetting of coals and lignites has been carried on for many years in Europe, and has reached a particularly high state of development in France, Belgium, and Germany, it has made comparatively little progress in the United States. The causes for the backwardness of the United States in this regard are several, and first among them has been the abundant supply of cheap raw fuel with which the manufactured article has to compete. With our millions of acres of coal-productive territory, from which the product can in moat cases be cheaply extracted, it has appeared in many districts more economical to waste the slack or culm, which constitutes a considerable percentage of the product, than to attempt to save it at the additional expense required for briquetting. It is for this reason that the view in all sections -of the anthracite-region of Pennsylvania is marred by the unsightly culm-banks which encumber the ground, and that in some of the bituminous-districts one sees huge piles of unmarketable slack allowed to burn up in order to get rid of them. When the coal is of a coking quality, or when the slack can be used for steaming-purposes, these losses are not sustained, but many thousands of tons of what might be converted into usable fuel have been wasted every year simply because of the increased expense involved in its preparation.

Jan 1, 1908

By William P. Blake

The salt-beds at Salton, on the line of the Southern Pacific railway, in San Diego county, California, have been successfully worked for many years by the corporation known as the East Liverpool Salt Co., and the salt has been largely used upon the Pacific coast generally and in the interior. But the industry has lately been destroyed by the overflow from the Colorado river. The salt is dissolved, and the waves of the Salton sea now roll 50 ft. above the site of this once thriving and growing business. The salt-bed was evidently the residual accumulation from the waters of an ancient lake, which I have named Cahuilla, from the name by which a large part of the valley—the home of the Cahuilla tribe of Indians—is known. The deposit covered a comparatively small area in the lowest part of the valley, 280 R. or more below the sea-level. This depressed area is now generally known as the Colorado desert, but has a soil of wonderful fertility wherever water can be had on its surface. The deserted beaches, and the water-lines, only a few feet above tide-level, upon the rocks of the bordering mountains, as well as a great abundance of shells in the soil, all bear decisive testimony to the former occupation of the valley by water. The depression is topographically the northern end of the Gulf of California, from which it is now separated by the delta of the Colorado river, extending practically from the mouth of the Gila river across the valley to the coast mountains on the

Jan 1, 1908

By Hjalmar Sjögren

Introduction.............767 Group I. The Ores of the Archean Crystalline Schists.... 770 Distribution............. 770 The Rocks.............770 Structures............772 The Rocks of Norrbotten..774 The Ores.............775 Type A. Apatite.Ores..........776 Type B. Mixed Hematite and Magnetite..777 Type C. Quartz-Banded Ores....777 Type D. The "Skarn" .Ores l..778 Type E. Limestone-Ores,..779 The Origin. of the Ore-Deposits......... 779 Arguments against the Sedimentation Theory,... 780 Concentration and Transformation within the Deep-Seated (Ana-morphic) Zone........783 The Chemical Changes.......784 Transformations in the Surface.Zone....789 The Graingesberg and Norrbotten Deposits,.....791 Analogous Deposits........794 Group II. The Ores of the Porphyries (Keratophyres) ... 796 Kiirunavaara. Luossavaara and TuoIlavaara....797 The Syenite.........799 The Porphyry of the, Foot. Wal1 .....799 The Porphyry of the Hanging-Wal1 ....799 The Ores.........800 The Forms and Dimensions of the Ore-Bodies ..802 Contact-Zones........803 The Genesis of the Deposits .......804 Mertainen and Painirova.......806 Ekatrömsberg..........808 Analogous Deposits,........808 Group 111. Magmatic Seregations in Basic Eruptives,... 809 Taberg in Smaland,.........811 Segregations in Diabase Younger than the Dala Sandstone, . 814 Iron-Ore in Nepheline. Syenite.......815 Ekersund and Soggendal in Norway......816

Jan 1, 1908

By Albert Hill Fay

In giving a sketch of the geology and mining of the tin-deposits of Cape Prince of Wales, a short description of the geographic and climatic conditions may be of special interest on account of this being a part of the world of which very little is known, even by the reading public. As shown in Fig. 1, the location of the Cape is lat. N 65° 35&apos; and long. W. 168o. It is bounded on the north by the Arctic ocean ; on the west by Bering strait and on the south by Bering sea. It is the Westernmost point of the mainland of North America, and to the west, across the strait, one can see East Cape, Siberia, which consists of a rugged, steep coast of granite cliffs. The climatic conditions arc of interest because of the part they have had in the surface geology, and also because they affect mining from an economic standpoint. In connection with the climate and geography, it does not seem out of place here to quote a few lines from the prologue of The Wandering Jew, written by Eugene Sue, under the caption " The Land&apos;s End of Two Worlds." "The Arctic Ocean encircles with a belt of eternal ice, the desert confines of Siberia and North America—the uttermost limits of the Old and New World, separated by the narrow channel known as Bering&apos;s Straits. " To the north, this desert is bounded by a ragged const, bristling with huge black rocks. At the base of this Titanic mass lies enchained the petrified ocean (Bering sea) whose spell-bound waves appear fixed as vast ranges of ice mountains, their blue peaks fading away in the far-off frost-smoke, or snow-vapor. " Between the twin peak* of East Cape, the termination of Siberia, the sullen sea is Been to drive tall icebergs across a stream of dead green. There lies Bering&apos;s Strait. Opposite, and towering over the channel, rise the granite masses of Cape Prince of Wales, the headland of North America. "These lonely latitudes do not belong to the habitable world."

Jan 1, 1908

By Thomas Leonard Watson

I. Historical. Barite has been mined for many years in various parts of Virginia, probably the earliest mining-operations being in Prince William county, within 600 ft. of the Fauquier county line, about 4 miles south of east from Catlett, a station on the Southern Railway. It is claimed that the mineral was mined here as early as 1845. Mining-operations in Campbell and Pittsylvania counties in the Piedmont region, and near Marion in Smyth county, in the southwest Virginia Valley region, were begun about 30 years ago. The mining and milling of barite on a commercial scale in Tazewell and Russell counties are more recent, and commenced about 15 years ago. II. Geographical and Geological Distribution. Barite occurs in many counties in the State, as shown in Fig. 1, but the industry has been confined to only a few of them. Its occurrence is noted in two of the three major divisions of the State—namely, the Piedmont region east of the Blue Ridge, and the Paleozoic area west of the Blue Ridge. In the Piedmont region the mineral has been mined in the following counties: Bedford, Campbell, Louisa, Prince William, and Pittsylvania. In the region west of the Blue Ridge, composed of Paleozoic sediments, barite has been mined in Montgomery, Russell, Smyth, and Tazewell counties. Of the counties mentioned, Bedford, Campbell, and Pittsylvania of the Piedmont region, and Russell, Smyth, and Tazewell of the Valley region, have been the principal producers. In 1906, operations were confined to five counties—Bedford, Louisa, Pittsylvania, Russell, and Tazewell—but in the first two counties named there was no production, the work being solely development.

Jan 1, 1908

By W. O. Crosby

The crystalline belt of the Atlantic Seaboard, south of New York, attains its maximum breadth of 220 miles on the northern border of North Carolina; arid in this State it is most widely characterized by the occurrence of gold in workable deposits. Half a dozen auriferous belts have been recognized by Nitze and Hanna.&apos; These are, in the main, coincident in position and trend with the NE.—SW. zones of metamorphic slates and schists, which, more than any other feature, give character to the geological map of North Carolina. The central gold-belts, accompanying the main zone of slates and as-

Jan 1, 1908