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By P. A. Korpi

In March of 1978 the first set of Angular Spiral Liners utilized in grate discharge ball mills for wet grinding was put into service in the San Flanuel Concentrator of Flagma Copper Company. The use of these liners has decreased grinding media consumption by 19.2% and grinding energy consumption by 15.8%. In addition a 1.1% increase in grinding throughput is being realized through the use of the system. This paper describes the Angular Spiral Lining System and reviews the test program at the San Manuel Arizona Concentrator. Operating parameters are discussed in addition to the current testing program to futher optimize the system.

Jan 1, 1982

Jan 1, 1999

By Mary Nelima Ondiaka, Oladunni Oyelola Alabi, Fatai Olufemi Aramide, Francis Gitau, Talabi Henry Kayode

Iron ore is essential in steelmaking but high-grade ores have diminished, making it necessary to turn to low-grade ores, which need further beneficiation to upgrade the iron content. Biobeneficiation techniques such as bioleaching, bioflotation and bioflocculation have proven successful in iron ore processing. Consequently, these methods have emerged as sustainable alternatives to conventional beneficiation. The biobeneficiation processes occur in mild conditions using bioreagents and biosurfactants derived from microbes, and offer a reduction of chemicals used in processing. This potentially offers methods that are relatively energy efficient, cost effective and environmentally friendly while tackling the constraints of dwindling high-grade iron ore resources.

Sep 1, 2024

By Harry M. Conger

Kaiser Steel Corporation's Eagle Mountain Mine is located in the Colorado Desert, 60 miles east of Indio, California. Concentrates from the mine are shipped by rail 164 miles to the company's steel mill at Fontana, and also to Longbeach, California for export. Temperatures are typical of the lower desert ranging from a high of 120 degrees in the summer to a low of 25 degrees in the winter. The average annual rainfall of about two inches comes mainly as cloud bursts during the summer months. From its inception, the Eagle Mountain Mine has had the problem of breaking its mine rock. Practices followed from 1949 until 1962 were very costly, did not produce uniformly good fragmentation, and were incapable of sustaining high production. During this period, every conventional type of explosive then in use was tried and found to be unsatisfactory for one reason or another. The first slurry test work at Eagle Mountain was started in 195E and finally by 1962, after having tried all the slurry mixtures then available including some "home made" formulas, a metallized slurry was perfected at the mine which overcame all of the disadvantages of former blasting methods.

Jan 1, 1965

By Takahide Wakamatsu, Junji Shibata

Complex polymetallic sulfide ore deposits occur in Tohoku district, northern part of Honshu island, Japan. The ore is locally called "Kuroko” ( black ore ) and is compactly composed of fine grained sulfide minerals of such principal metals as copper, lead, zinc and iron. Currently one of Kuroko mill plants is producing such concentrates as copper, lead, zinc, pyrite, barite, and clay minerals, mainly employing differential flotation techniques. This paper describes briefly the progress of techniques in Kuroko processing over the past thirty years and also the present state of Kuroko processing and its challenges to be studied and overcome in the future.

Jan 1, 1989

By Peter T. Luckie

Up until the past couple of years, thermal coal dryers were only used to dry midwest and eastern United States bituminous coals. These dryers were primarily installed at coal preparation plants to freeze proof the coal and lower the transportation costs per BTU. Today thermal coal dryers are being specified to dry western sub-bituminous and lignite coals for these and other reasons brought about by the intense interest in coal gasification and liquefaction. One reason for drying western coals ahead of a coal gasification plant is the elimination of surface moisture which would prevent efficient sizing of the coal, since feed material size consist is very important in most commercial coal gasification processes. Thermal dryers are being proposed for liquefaction processes because of the need for a feed material containing approximately 4% or less total moisture Future coal gasification processes may also need to reduce feed material moisture content.

Jan 1, 1975

By James A. Barclay

Results of investigations over approximately the last 10 years by the Bureau of Mines and others on technology for recovering cell-grade alumina from domestic nonbauxitic resources such as clay, anorthosite, alunite, dawsonitic oil shale, coal ash, and coal shale are reviewed. It is concluded that, although many innovative techniques have evolved from this effort and have been shown to be technically feasible, energy and economic considerations will prevent any of the processes from competing with the Bayer process under normal conditions. Based on the Bureau's experience, some variation of clay-HCI leaching, HC1 gas sparging crystallization has the greatest potential as an alternative to the Bayer-bauxite process.

Jan 1, 1984

By Robin J. Batterham, Stephen H. Algie

It is often stated that innovation is central to the economic survival of mining and mineral processing in the face of global competition, and yet technology is often far from a core strategy in our industry - hence the concerns that are often voiced about the apparent slow rate at which new technology is applied. Much of the discussion stems from a lack of understanding of the role of technology in innovation, and of the role of R&D within the innovation process. To a large extent this has all been said, however, the messages are clear and deserve repetition. This paper expresses the personal views of the authors, based on experience in government-funded (CSIRO and universities) research, and in CRA Ltd, a large mining and mineral processing company. Further than this, it explains how our own development unit within the CRA Group has come to see its key roles as including the transfer of technology, and the training of technologists to move into the operating business units. We conclude that these critical tasks are the keys to creating the environment that will allow us to maximise the contribution of technology.

Jan 1, 1995

By D. L. Jones, S. Knoerr, J. Mansanti

The Buckhorn Mine in Nevada currently treats oxide ore using heap leach methods, but exploration has identified sulphide reserves which are refractory in nature. Preliminary testwork was conducted on the sulphide material to screen potential pre-cyanidation treatment methods. Processes evaluated included pressure oxidation, biological oxidation, nitric acid oxidation and roasting. An initial economic and process analysis of the results concluded that roasting was the only viable process, and only if the roaster off-gases were converted to soleable sulphuric acid. Further economic analysis indicated that roasting of the whole ore was more attractive than pre-concentrating by flotation, followed by roasting of the concentrate. These results were generalized to show that for high sulphur ore a roaster/acid plant combination is more attractive that either of the other options, ie. pressure leaching or bioleaching, provided the by-product acid is soleable.

Jan 1, 1990

By Holger Witthaus

Various seam conditions had been examined during longwall production at RAG German hard coal mines. Based on the field data a prediction method was developed considering separation planes as influencing factors for roof falls at the face. The characteristics, orientation, and density of separation are important factors on the occurrence of roof falls. In addition to geological influences, the performance parameters and geometry of support must be considered and optimized for the prediction and prevention of roof falls in a longwall face. Based on detailed macro- and microscopic investigations of e coal seams considering various ranks of carbonization, the origin and characteristics of separation planes are determined and a strata-specific influence on roof fall is interpreted. It was assessed that the coal face fracturing and displacement caused by the stress depend on the floor and roof strata conditions due to activation of the existing separation planes. Field studies are shown giving an idea of influences by advance rates of the longwall face, support delay and hydraulic pressure to the roof control in longwall faces in depth of more than 3000 ft. The analysis includes the application of specific software developed for longwall roof fall prediction as a result of a European research project. The software allows a laminar graphic display of roof fall probability, which is used for recognition of risk areas and risk management.

Jan 1, 2009

By BHAMIDIPATI S. SASTRY, SRIVATSAN J. SRIDHARAN, ANMAYA NAIK, ASIF AHMAD, ADITYA PANDEY

Wet kata cooling power (WKCP) measured using a kata thermometer is a well-known heat stress index in mining industries. Although over the years several researchers have proposed different heat indices and indicated the limitations of the kata thermometer, it is still being used in many areas, especially in the South African gold mining industry, mainly because of its simplicity and rapidity of assessment. This paper presents a comparative analysis of the newly developed empirical expression for WKCP, and some of the more prevalent empirical expressions. The analysis presented based on a regression technique aims to assess the disagreement between model predictions and actual measurements. It is found that the WKCP expresses bioclimatic interaction quite well under the specific parameter of interaction that explains the harsh thermal environment and air condition, such as metabolic activity, the person’s clothing, and the velocity of the air in which the person is working. The statistical analysis shows that the WKCP exhibits significant estimates to thermal stress under lower air velocities, light clothing, and higher metabolic activity rates.

By Andrzej M. Wala

The determination of the air quality needs to dilute diesel exhaust gases to a safe level must be individually evaluated for particular cases. One such case is when diesel-powered vehicles are working in long dead- end headings with forcing auxiliary ventilation. The vehicles perform specific operations in a cyclic order required by the technical process. The dynamics of this process in certain conditions has a vital influence on environmental conditions in the working area and in the rest of the heading. Recent studies on diesel gas behavior in long headings have shown a zone of increased concentration of pollutants (accumulation) between the face and the mouth of the heading. To be able to control these accumulations of pollutants, use of the concept of planned air discharge by using the Coanda-type ducts is proposed. The main objective of this paper is to demonstrate an application of computer simulation of that process. It is shown that, by planning the additional air discharge, the concentration of diesel gases can meet required limits along the heading.

Jan 1, 1987

By Fatima-Zahra Houmymid, Elena Chiriotti, Mahdi, Samy

"The Greater Paris projects involves the creation of a 200km extension of the actual public transport network on the close outskirt of Paris. In 2011, SYSTRA has been awarded the Engineering studies of a 20km underground section in the densely urbanized southeast quarter of the Parisian suburb. In order to both guide the TBM technology choice and identify and mitigate the risk due to soil settlement during tunnel boring, several analysis have been carried out and integrated into a Geographical Information System to share and manage this risk during the successive design phases of the project. The geological context‘s complexity and the Owner‘ requirements have led to the necessity of using an innovative analysis approach, leveraging both the numerical modelling analysis’s accuracy and the analytical method‘s ease of programming and implementation in a GIS, by the mean of the calibration of the analytical approach’ parameters on the FEM results.INTRODUCTIONThe Greater Paris Transport Project foresees the extension of the actual public transport network to the close outskirt of Paris through the extension lines 11 and 14, the creation of a circular new line around Paris - line 15 completed by lines 16 and 18 linking developing territories - and line 17 to Roissy-Charlesde- Gaulle airport.The SOCIETE DU GRAND PARIS (SGP) is the public institution that promotes this project and awards SYSTRA as Engineering for the 15th Line southeast section.Line 15th – South-East sectionIn 2011, the Owner SGP (SOCIÉTÉ DU GRAND PARIS) awarded to SYSTRA the preliminary and detailed design of a 20km-long underground section of Line 15, between the stations of Villejuif-Louis-Aragon and Noisy-Champs. The double-track, single-tube tunnel has an inner diameter of 8.5m (about 9.8m excavated diameter, 75m2 excavated cross-section). The tunnel is inserted in a densely urbanized context."

Jan 1, 2016

By L. E. Krys, K. D. Harrison, C. G. Anderson

Since 1984, nitrogen-species catalyzed pressure leaching has been utilized at Sunshine Mining and Refining Company for the recovery of precious metals from a refractory sulfide concentrate. The process operates without the use of cyanide. The plant is now the only industrial-scale commercial application of this technology. Since the inception of the process, changes have been implemented to improve efficiencies and throughputs. Two of these changes, the replacement of nitric acid by sodium nitrite and a concentrate regrind, have recently been implemented. This paper discusses the development and potential mechanisms involved in these recently patented plant-process changes. A companion publication (Anderson et al., 1996) covers the plant integration and potential applicability of the technology.

Jan 1, 1997

By Lawrence A. Roe

This paper describes research and development efforts leading to a wet process for the beneficiation of Western talc ores in which the values are primarily present as soft, platy talc mineral. The mineralogy of the ore, as it relates to the logic of utilizing an uncomplicated, attrition-scrubbing sedimentation process is described. Bench-scale laboratory testwork and a pilot-plant test program are described. The pilot-plant program included production of several tons of products. The thickened talc slurries were very difficult to dewater prior to the drying step. Dewatering difficulties were overcome by use of a high-speed centrifuge. The centrifuge cake was dried either by tray, flash or spray drying. The successful use of one high-grade talc product as titanium dioxide extender in paper is discussed. The talc product has extremely low abrasion values, an important characteristic for minerals used in paper manufacture. It is concluded that this wet process for soft talc ores is capable of producing high-purity talc products for paint, paper, cosmetics and other industrial uses re-quiring very pure soft talc.

Jan 1, 1972

By A. A. Odunaike, E. G. Okafor, M. H. Mokwe

Microscopic Studies were performed on ore samples from the Muro banded iron ore deposit in Nigeria and the Marampa iron ore deposit in Sierra Leone. Ore characteristics that affect processing of both ores were compared with a view toward assisting mineral processing engineers in choosing the most suitable methods for upgrading the ore. The Nigerian ore contains 30% to 37% (by weight) Fe and the Sierra Leonean ore contains 34% to 51% (by weight) Fe. Hematite is the main iron mineral in both ores. The Sierra Leonean ore is relatively coarse grained (typically around 250 µm) and can be upgraded by conventional gravitational methods. In contrast, the Nigerian iron ore is fine grained and must be ground to -74 µm to liberate the hematite for recovery by flotation. Both ores contain high percentages of phosphorus and sulfur, which are above the required specifications for direct reduction and blast-furnace practice. These deleterious elements can be rejected by grinding and flotation.

Jan 1, 1999

By H. Yoon

Several processes involving injection of sorbent and humidification water downstream of the air preheater in a coal-fired boiler unit, are being developed as low capital cost retrofit S02 control options. Extensive laboratory work, pilot plant programs and larger scale programs have developed performance data and design information. Many of these programs were supported by the U. S. Department of Energy (DOE) as "proofs-of-concept" of three different processes proposed by Dravo, Bechtel and General Electric. Based on these project results, DOE formulated a comprehensive in-duct sorbent injection development program to fully commercialize the technology by 1992. Also, EPRI will conduct a 4 MWe pilot program to develop its HYPAS process. The Consol Coolside process is scheduled for utility demonstration in 1989 on a 104 MWe unit at the Ohio Edison Edgewater Station under partial sponsorship of the DOE Clean Coal Technology Program.

Jan 1, 1989

By I. O. Otunniyi

The natural hydrophobic response flotation method for beneficiation of printed circuit board comminution fines (PCB CF) still requires many studies to further basic understanding of the process and the flotation traits that the PCB CF presents. Varying particle size distribution (PSD) and water recovery under the scheme show that higher mass pull, obtained at the finer PSD, gave lower water recovery but higher value loss. The reverse also holds: the least mass pull at the coarsest PSD used, -106 + 75 µm, gave the highest water recovery per unit mass pull with the highest reverse recovery. This is unlike what obtains in primary resources processing, where higher water recovery is often with increased fines entrainment. The reverse recovery loss here is, therefore, more due to entrapment with the heavy mass pull characteristic of the method than to the entrainment of value with water. Other peculiarities of the system observed are discussed, with the goal of improving the performance of the process, and broadening the general knowledge of flotation systems.

By Milton E. Wadsworth, M. Ken Han

The kinetics of leaching of galena in hydrochloric acid solutions with sulfur dioxide gas have been investigated experimentally. The leaching method is then applied to complex sulfide concentrates to evaluate its selective leaching capability and to develop a new hydrometallurgical lead extraction process based upon the method. The leaching reaction follows a linear rate with an activation energy of 61.9,KJ/mole. The rate Is of first order with respect to the product [H+] [Cl-] . Excel lent selective leaching capability f s demonstrated and an attractive hydrometallurgical process flow sheet is proposed.

Jan 1, 1989

By Sean E. Armstrong, Deepak Malhotra

The current trend in gold ore processing is the development of lower grade or highly refractory deposits. The perplexity of treating low grade oxidized ores has been adequately addressed by heap leach technology. However, refractory gold ores are very difficult to positively characterize the gold association within the mineral matrix. Gold accompanied with refractory sulfitlc or carbonaceous mineralization can often be sub­micron In size and occur interstitially. Mineralogical examination of these ores Is difficult, expensive, and occasionally Inconclusive. Hence, the metallurgist Is given little information for the selection of processing alternatives. The purpose of this paper Is to demonstrate the use of diagnostic leach procedures to assist the metallurgist' s decision-making process to solve some of these problems. By sequentially liberating and/or leaching gold associated with specific minerals, the amount of recoverable gold in each stage can be determined. Through careful interpretation of the results obtained by diagnostic leaching, the metallurgist can devise a flowsheet for treating the ore or solve a problem at an existing plant

Jan 1, 1992