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By Gabriella Vaschetti, Pascual Perazzo

A paper presented at Perumin 35 in 2022 described the concepts and a state-of-the-art system with extruded curbs and PVC anchor wings, adopted among others at the first four stages of Las Bambas tailings dam in Peru, discussing how upstream geomembrane water barriers can mitigate the numerous issues, including environmental aspects, of tailings dams’ design and operation. This paper, beside presenting a summary of what has been carried out so far at Las Bambas, amplifies the subject, presenting the results by means of the data of the leakage monitoring system, showing that the flow monitoring data at the downstream toe are seasonally consistent, and in alignment with design predictions.

Sep 29, 2023

By Sergio Sanchez-Segado, Yuan Zhang, Animesh Jha, Ahmad Fahmi Ruzaidi

Niobium and tantalum are considered critical materials because the increasing demand in the energy sector which is reliant on limited abundance of these two metals in minerals. Traditionally, niobium and tantalum mineralsare digested using hydrofluoric acid at moderate temperatures, producing oxy-fluorides which are separated by solvent extraction, involving the use ofhazardous chemicals. The increasing environmental pressures are forcing the industry to search for alternative low carbon processing methods. In this paper alkali roasting based separation and beneficiation, which is not well understood in the literature, is proposed, for which the kinetics and thermodynamic equilibria for the formation of sodium tantalate and niobate with sodium hydroxide are analyzedat the temperature range of 400ºC to 700ºC. The apparent activation energy of formation,changes from 31.0±0.8 to 22.3±1.2 kJ mol-1 and from 23.8±1.2 to110.2±12.8 kJ mol-1, for tantalate and niobate, respectively. The reaction mechanism is examined on the basis of the analysis of reaction products using X-ray powder diffraction (XRPD) and X-ray fluorescence (XRF).

Jan 1, 2015

By Ben Bowman

For certain ferroalloy furnaces, such as ferrochrome or ferromanganese, there is still doubt about the mechanisms operating under the electrode tips. In this paper a model is built that does not call upon an arc. The medium is best described as an electrically conducting slurry, a mixture of liquids, solids and gas. There are two sources of propulsion, the Lorentz force within the conducting part and buoyancy generated by CO bubbles, creating two opposed poloidal circulation loops, downward below the electrode axis and upward further out.

Jan 1, 2014

By R. Jacobs, R. E. L. Pobe

The Moab Khotsong Metallurgical Complex comprises a gold recovery circuit (Noligwa Gold Plant) and a uranium recovery circuit (South Uranium Plant). The metallurgical complex employs the reverse leach technology for the recovery of uranium; specifically, uranium extraction prior to gold using acid leaching processing. The inherent uranium species in the ore are uraninite, coffinite and brannerite. The slurry that has been subjected to the uranium leach is further subjected to solid-liquid separation to separate the uranium in a solution through counter-current decantation and the solids (solids carrying all the gold), which are repulped and returned to the gold plant for gold processing. The uranium leaching process is critical to the uranium playing a pivotal role as a value adding by-product to the gold operation. The benefit of adopting this reverse leach process, for improved gold recovery, is that it exposes gold particles occluded within the uranium matrices and avails them for cyanidation. However, the drive for operational efficiency in uranium extraction must be weighed against the incremental operating cost against the backdrop of depressed spot uranium market prices. Over the years, efforts were directed at maintaining the benefit of extracting uranium to enhance gold recovery and simultaneously, optimising the operating cost model for the uranium operation to remain relevant to the gold operation. The aim of this paper and the corresponding presentation is to give an account of the uranium processing optimisation journey embarked on over the years; namely, the operational tradeoffs made in the process of ensuring that uranium continues to add value to the gold operation. These challenges were faced while striking a fine balance between processing cost and operational efficiencies against the prevailing depressed uranium spot market prices. Mineralogical- and laboratory tests conducted form the support basis for the results and observations articulated in the paper. Keywords: By-products, gold extraction, reverse leach benefit, uranium extraction

Jan 1, 2020

By D. Pienaar, C. O’Connor, B. McFadzean

Dithiophosphate (DTP) is classically used as a co-collector in sulphide mineral flotation, where xanthate-DTP mixtures have been shown to synergistically improve mineral flotation performance. Notwithstanding the improved recoveries observed, ethyl DTP does not appear to behave as a conventional collector, since it has been shown that it does not adsorb onto certain sulphide mineral surfaces. Recent investigations have nevertheless indicated that when ethyl DTP does not adsorb onto the sulphide mineral surface, the presence of a non-ionic frother can activate a synergistic increase in pulp phase mineral recovery, and bubble-particle attachment probability. A regular solution approach was used to determine the interactions between thiol collectors and non-ionic frothers at the air-water interface. Attractive interactions were observed between longer alkyl chain DTPs and frothers, whereas the activity of xanthates at the air-water interface were too weak to determine if an interaction was occurring. This is the first time that such interactions have been shown for the DTP-frother system and represents an important contribution to our understanding of the role of DTP reagents in the flotation process. Keywords: Collector-frother interaction, dithiophosphate, surfactant synergism

Jan 1, 2020

By J. W. Drelich, H. Zeng, L. Xie, X. Cui, Z. Gao, M. Tian, Y. Hu, W. Hu, W. Sun

Flotation is a mineral separation technology that uses the surface hydrophobic difference of valuable minerals and their associated gangue minerals to separate them. The flotation collector adsorbs on the valuable mineral surface to improve its hydrophobicity, and metal ions are usually used as activators to enhance the collector adsorption. Different mineral surfaces show different charging properties and adsorption behaviours with the collector or metal ions. Moreover, the order of adding metal ions and the collector also show significant and different flotation performance for the same mineral. The adsorption or flotation behaviour or both are governed by mineral surface chemistry, such as surface charging and reactivity. In our recent studies, force measurement using atomic force microscopy (AFM) was employed to study the surface charging and adsorption mechanism of metal ions and collectors. By preparing collector-functionalised AFM tips, AFM can directly measure the adsorption strength of the collector on the mineral surface to determine the anisotropy of mineral surface reactivity. The preparation of collector-functionalised AFM tips provides the foundation for further study of the activation role of metal ion in the collector adsorption. The application of AFM for force measurement in the surface chemistry of mineral flotation can provide important information on developing flotation reagents and lays the foundation for the specific regulation of mineral surface characteristics. Keywords: Scheelite; flotation; surface chemistry; AFM force measurement

Jan 1, 2020

By Fernando Hernández Polanco

Transportation and handling metals and alloys from mills to consumption factories as well as dosing in conventional processes with ingots and scrap has always been considered a complicated activity with high operating costs. Several manufacturers of ferroalloys willing to solve these problems have chosen an alternative for their products that can be used to secure, during transport and dosage in the processes to making special steels, with more efficient consumption of ferroalloys. The trend for the production and sale of ferroalloys is to provide the product in the form of granules packed in bags or in bulk. In this paper we will show you how the granulation process was developed and rapidly adopted the ferroalloys industry as an effective solution to reduce operating costs, create cleaner and safer working environments.

Oct 30, 2017

By Valdicleide Silva Mello

Nowadays the biodiesel use is obligate in Brazil, in order to reduce the emissions of fuel burn. However, it is important to analyze which percentage of biodiesel is necessary to keep or improve the lubricant action of fuel for diesel engine, as well which kind of biodiesel give better performance. Therefore, this work aims to analyze the parameters that keep the lubricant action of biofuels, by using the Box-Behnken design type to optimize them. In this design was evaluated the input parameters: the type of the biodiesel (soybean, sunflower and palm), the concentration (5%, 20% and 100%) and the temperature of contact (25°C, 40°C and 60°C). The analyzed output parameters were the percentage of film formation, coefficient of friction, wear scar diameter (WSD) of ball, these output parameters were obtained by HFRR tribometer and they were analyzed applying response surface methodology. With this methodology was possible to determine the simultaneous influence and the interactions between two or more independent variables investigated. The response surfaces generated for the coefficients of friction, WSD, film formation showed a higher lubricant action for higher levels of concentration of biodiesel. An increase in lubricant action was found to high and intermediate temperature.

Jul 31, 2018

By Yasser Ghobara

Phosphorus is a problematic impurity that has challenged steelmakers for decades. Steel producers have developed specific technologies to eliminate phosphorus prior to and during steelmaking. These process technologies reduce phosphorus to various degrees and increase the cost of making steel. The state-of-the art dephosphorization technologies are described and operating costs compared for each of the established technologies. Costs are discussed in terms of price penalties for high P iron ore and selling premiums for low P steel. From this, strategies to control P in a cost effective manner are described.

Aug 17, 2017

By A. Melkumyan, M. Balamurali, J. Zigman

Understanding the contribution of geophysical variables is vital for identifying ore indicator regions. Both magnetometry and gamma-rays are used to identify the geophysical signatures of the rocks. Density is another key variable for tonnage estimation in mining, and needs to be re-estimated in areas of change when a boundary update has been conducted. Modelling these geophysical variables in 3D will enable investigation of the properties of the rocks and improve our understanding of the ore. The Gaussian Process (GP) was previously used to generate 3D spatial models for grade estimation using geochemical assays. This study investigates the influence of the following two factors on the GP-based autonomously generated 3D geophysical models: the resolution of the input data, and the number of nearest samples used in the training process. A case study conducted on a typical Hammersley Ranges iron ore deposit using geophysical logs, including density, collected from the exploration holes, is examined in this paper.

Sep 1, 2021

By Thomas Jancic

Two of the open-pit, copper-molybdenum mining operations of Duval Corporation are located in the foothills of the Sierrita Mountains approximately 30 miles southwest of Tucson, Arizona. In March 1959, mining from a moderate sized porphyry deposit known as the "Esperanza orebody" was begun at a rate of 10,000 tons of ore per day. Some five years later, a sizeable group of mineral claims west of Esperanza became available to Duval. Earlier exploration and development drilling in this area by others indicated an orebody of greater size but lower tenor than that of Esperanza. A drilling program conducted by Duval not only verified the results of the prior drilling but in addition, revealed a continuation of the mineralization to the south and east. Thus was developed the Sierrita orebody. Open pit design delineated 414 million tons of ore containing an average copper content of 0.35 percent and a molybdenum content of 0.036 percent. In April 1966, the office of Emergency Planning authorized General Services Administration to undertake a program under the Defense Production Act to en¬courage additional domestic production of copper in the interest of national defense. Duval's Sierrita Project was brought to GSA's attention in May 1966 on November 28, 1967, an agreement providing for the development of the Sierrita Property was consummated with GSA. In March 1970, the first copper-molybdenum concentrates were produced in the 72,000 tons-per-day concentrator. Pre-production stripping exceeded the scheduled 105 million tons despite the comparatively short lead time available to equip the mine, build the mine plant facilities, and staff the technical, supervisory, and labor forces. Shortly before the first concentrates were produced, plans were being formulated for a program to increase processing capacity by approximately 15 percent, which entailed increasing overall mining capacity by approximately 50,000 tons per day. This program is scheduled for completion early in 1971.

Jan 1, 1971

By M. Ahmadiantehrani

The concept of hypochlorite treatment prior to cyanidation in the heap leaching of low grade carbonaceous gold ores is discussed. Laboratory column leach tests using a low grade carbonaceous ore were performed to investigate the effects of pH, concentration, hypochlorite consumption, and bed height on the total gold extraction. At high pH, the hypochlorite stability increases and thus, hypochlorite consumption is decreased. At room temperature, the total gold extraction is proportional to the hypochlorite consumption. However, at some point additional hypochlorite consumption does not increase gold extraction. Gold recoveries of 10 and 80 percent are obtained for 12 and 167 lbs/ton hypochlorite consumption, respectively. Increasing hypochlorite concentration increases the rate of extraction. For a given hypochlorite consumption gold extraction was increased by shortening the ore column height. Finally, calcium hypochlorite is more effective than sodium hypochlorite.

Jan 1, 1990

E. K. Landis, Philadelphia, Pa. (communication to the Secretary) : Mr. Firmstone's paper is of great interest; but he has unfortunately otnitted to state the most important point, viz., the percentage of sulphur in the two materials he compares; and this omission vitiates the conclusions which he draws. Comparing by grade, instead of silicon-contents (as in his Table III.), the iron made using limestone with that made using dolomite, we find for gray-forge the average of four analyses under limestone to be, Si, 0.644; S, 0.089 ; while one analysis under dolomite gives Si, 0.508 ; S, 0.070. For No. 2 iron, the limestone flux gives, as an average of 19 analyses, Si, 1.107; S, 0.051; while the average of 4 analyses made with dolomite flux gives Si, 0.630; S, 0.056. It will be observed, that no No. 1 pig is given under limestone, while 14 analyses appear under dolomite, averaging Si, 0.950 ; S, 0.028. As nothing is said about changed conditions, it is Fair to presume that the ore and fuel, as well as the blast-temperature (which is stated to have been uniform at about 750' F.) remained practically the same; and since the sulphur in the two fluxes is not given, it is impossible to know whether the lower sulphur for equal silicon-contents is due to the use of dolomite or to other conditions. The use of dolomite would produce a more fusible cinder, and the furnace would be hotter than when using limestone; therefore, we might expect to see a grayer iron. The amount of So. 1 iron made with dolomite seems to confirm this supposition; and, under these conditions, we might expect more of the sulphur to be volatilized, and to pass off in the gases. The easier fusibility of the cinder would also permit more rapid driving; and this should reduce the amount of silicon and sulphur in the iron, as the amount of reduced metalloids in the pig is directly proportional to the length of time it remains in the reducing-zone.

Jan 1, 1895

The Gj0vik Olympic Mountain Hall is the world's largest underground cavern for public use and was created primarily to facilitate the ice hockey tournaments for the 1994 winter Olympics in Norway. The cavern has a span of 61 m, is 91 m long and is 25 m high. Ordinarily, rock caverns have a span width of 15 to 25 m, however, temporary mining caverns of up to 60 m have been excavated and natural caves with even greater dimensions occur. The Gj0vik Olympic Mountain Hall is unique as it is for public use with a capacity for 5800 spectators. Blasting was conducted with a high production rate at normal costs due to detailed planning and strict supervision of each round. The initiation system and vibration monitors were the main tools to control vibration levels and to facilitate a high production rate. It was of utmost importance that the rock remaining in the roofs and walls was of high quality after blasting to avoid rock fall, rock slides and excessive maintenance work.

Jan 1, 1995

By Eugene L. Foster

The engineering profession has traditionally devoted its efforts to understanding and modifying the Earth's environment in order to adapt it to man's needs. In appraising our overall performance, I would have to say it has been a mixed bag. In many areas, notably communications taken in the broadest sense, and development of creature comforts, we have done a good job. In others, we have failed, particularly in our assessment of the effect of our work on the environment. Our failures have been due in part to a lack of understanding or foresight, and in part to a disproportionate emphasis on lowest first cost. Now, with an increasingly large number of people living in a finite environment, there is an urgent need for reassessment. It is no longer possible to pursue a single objective without regard to its side effects. Our projects are too large, and there are too many of them. Environmental impacts must be taken into account in all important engineering decisions of the future. There are forces at work which will help to bring this about. Thinking people everywhere have realized that adverse alteration of our environment eventually affects every one of us. The majority of our citizens, who now live in cities, are beginning to appreciate the advantages of a good natural environment in a way which others who have been closer to the soil have appreciated for years. Our people have flocked to the cities because they wanted to be "where the action is." At the same time, there is a strong desire for what we have come to call the quality of life. Today, we all want the standard creature comforts. We want to be able to move freely

Jan 1, 1974

By Paul M. Tyler

MILITARY power stems from industrial power and industrial power in turn depends predominantly upon an ample and assured supply of mineral raw materials. It thus becomes the duty of mineral economists to collate the vast array of data and logical deductions in order to reach an unemotional judgment as to the ability of the Soviet economy to withstand the strain of prolonged military action on the modern scale. Russian publications, reports: and official speeches have been laboriously screened and analyzed. Since these are the sources of information for the lower echelons of the Soviet industrial organization itself, they carry factual data that can be pieced together to show the present-day pattern. Apparent contradictions and obvious distortions or omissions can often be rationalized on the basis of observations made by foreign engineers and consultants during the 1930'5 and by checking against the technical literature published before even so-called technical articles were riddled by bombastic and presumptuous claims.

Jan 6, 1951

By E. J. Marcotte

"INCO LIMITED'S Shebandowan Mine and Mill is located in a scenic tourist and cottage area near the western tip of Lower Shebandowan Lake, approximately 90 Km west of Thunder Bay, Ontario. This nicely designed complex is a positive indication that mining operations can co-exist in harmony within the natural environment.The Shebandowan complex processed nickel-copper ore from 1973 to 1985, inclusive, after which operations were shut down.In late 1988, INCO LIMITED decided to place the Shebandowan complex back into operation, under contract, to mine and mill the remainder of the ore body, according to their specifications. MaclSAAC'S EXPLORATIONS was the successful bidder for the project. Following preliminary rehabilitation, operations were re-activated in late March, 1989. The ore mined to date is of a moderately lower nickel grade than the majority of previous years. However, a higher tonnage rate, combined with improved nickel recoveries, has contributed to a viable operation.A series of mill operating and equipment modifications has enabled MaclSAAC EXPLORATIONS to achieve the quality and grade of nickel-copper concentrates specified, and at the same time, expand mill tonnage throughput while attaining increased nickel recovenes."

Jan 1, 1992

By M. P. A. Hames, D. R. Beaumont

INTRODUCTION Legend has it that when Isembard Kingdom Brunel was confronted with the cost and consequences of one of his bridges having failed, he responded cheerfully that the event had saved investors and taxpayers a fortune because it prevented him from repeating the same design at several other locations. To meet the demands of rejuvenating and expanding the transportation system in an era of industrial growth Brunel and his contemporaries introduced bold designs and many innovations. Great advances in design and construction techniques resulted, yet these too had their practical limits as the story tells. In the gold mining industry today we face the same challenge of expansion, yet designers must respond mindful of economic restraints. Is innovation the answer? It has two meanings; to bring in novelties and to make changes. Distinguishing between improvement and novelties, or simply recognizing the benefits and limitations of new ideas over proven technology is part of good design. This paper will illustrate the practical aspects of selecting appropriate solutions to a design problem by examining a variety of examples common throughout the industry. Since a variety of engineering disciplines contribute to the design of a gold processing plant, and each has some old wisdom to impart or new development to boast this paper is divided into the different areas of expertise involved.

Jan 1, 1987

By Ronald M. Fedrick

The microtunneling project for the State of Hawaii's Natural Energy Laboratory (NELH) facility in Kona, Hawaii, was awarded to Nova Group Inc., Napa, California. Nova has developed both microtunnel and deep pile cofferdam experience. Both of which would be required for this project. The project was designed by Makai Ocean Engineering of Honolulu as a continuation of the Ocean Thermal Energy Project (OTEC). The world's first OTEC plant has been successfully operational at NELH since 1982 netting approx 50 kw of usable electric power from a gross generation of 210 kw. A second plant designed to draw 39°F cold water from 3,000 ft below sea level and produce a gross output of 1 mw with a net 500 kw of usable power required 2 - 54 in. finished diameter pipelines. An ongoing problem with earlier offshore pipelines has been the damage to the near-shore pipes within the surf zone. The necessity for a deeper connection between the land based pipe and submerged sea pipeline was obvious. Earlier pipelines had been drilled and shot through the shoreline. This process was only practical at shallow depths. Makai Ocean Engineering and the NELH scientists looked at different methods to get the pipeline through the shoreline at a depth of 80 ft below sea level. Initially, the direction drilling method was proposed as the most potentially practical method. A contract was awarded and various attempts were made to complete a successful

Jan 1, 1995

By Robert Bell

The regions to which this paper refers include the whole of the Dominion of Canada east of the 130 Rocky Mountains and north of the water-shed of the St. Lawrence. Very little exploration for economic minerals has yet been done in this immense country; but that little has already served to indicate great wealth in some localities. Having been engaged for a number of years in conducting government geological explorations in these vast territories, I shall endeavor to give the members of the Institute an idea of the prospective mineral resources of almost half a continent, as far as they are yet discernible. I purpose confining my observations to the economic minerals, and will not attempt a description of the geology of these territories; hut it will be necessary to say a few words about the rocks in order the better to explain the distribution of such minerals. The Laurentian nucleus of the continent is the principal feature of the geological map of the Dominion. It stretches from Lake Superior to Baffin's Bay, and from Great Bear Lake to the Straits of Belle Isle. Hudson's Bay itself, which is half the size of the Mediterranean Sea of the old world, lies in the center of this area. Its shores are bordered in places with newer rocks. On the west side of James' Bay (its southern prololigation) these extend inland over 200 miles, and consist of fossiliferous Devonian and Silurian strata. On the western and northwestern side of Hudson's Bay proper, altered rocks are met with, some of which resemble the gold-bearing strata of Nora Scotia, some the Huronian of Lake Huron, some the older Huronian, and others the crystalline series of the neighborhood of Sherbrooke in the Province of Quebec. Along the east coast (called the Eastmain)and among the islands lying off it, there is an interesting set of volcanic and sedimentary rocks which appears to be identical with the Animikie and the Nipigon series of Lake Superior. The area which I have characterized in a general way as Laurentian, includes tracts and belts, more or less extensive, of the Huronian series. Such areas appear to be most common, and have been best explored, in the country between the Great Lakes and Hudson's Bay.

Jan 1, 1886