Search Documents

By R. R. Dorfler

The existing regrind circuit at the Climax Operations uses sodium cyanide and Nokes reagent to reject pyrite, copper, and lead minerals. Laboratory flotation studies were performed using feed to flotation following first-stage regrinding. The effects of conditioning time, pH, and the concentration of depressants such as Nokes reagent and sodium cyanide on the rejection of pyrite, lead, and copper minerals were investigated. The metallurgical results indicate that, in the presence of depressants, the rejection of copper is strongly dependent on the pH. Preliminary mill testing confirmed the finding. The rejection of impurities is also dependent on conditioning time. The recovery of molybdenite is independent of the variables investigated.

Jan 1, 1981

By M. Akser

Ilmenite, rutile, and zircon deposits of commercial importance have not been reported to-date from Turkey. However, information from recent reconnaissance activities indicates the possibility of an economically viable heavy-mineral deposit along the Black Sea coast of Turkey in the vicinity of Ormanli, northwest of Istanbul. Consequently beach and sand dune samples were collected from that area for additional analysis. Laboratory methodologies, designed to simulate standard industrial heavy-mineral plant practices, were used to analyze and evaluate the samples. Based on the analyses, and current market needs, none of the deposits in the Ormanli area qualify as a commercial heavy-mineral deposit.

Jan 1, 1995

By A. P. Grobbelaar

Andalusite is a member of the sillimanite group of minerals consisting of andalusite, kyanite, and sillimanite. These minerals are the structural polymorphs of Al,Si05 (the anhydrous silicate of aluminium) and although chemically similar, they differ in physical properties due to their different crystal structures. For further information on the sillimanite group, see the chapter on Kyanite and Related Minerals that follows. The minerals are generally the products of the metamorphism of alumina-rich sediments and are found in schists, gneisses, or hornfelses, which have undergone either regional or thermal metamorphism from their original form. Sedimentary deposits may also form since the minerals are chemically and physically resistant to breakdown. When heated to a sufficiently high temperature the sillimanite group minerals convert to mullite with a resultant volume expansion and the liberation of silica. Due to the stability of the mullite formed, its high hot strength and resistance to chemical and physical erosion, they are widely used in the manufacture of refractories and special ceramics (Table 1). The reaction can be represented as follows: [ ] The worldwide use of these minerals depends to a large degree on their availability (Fig. 1). Andalusite, with its lower conversion temperature and the lowest volume expansion on being heated is the natural choice as a raw material to produce energy-saving refractories without prior calcination. The Republic of South Africa holds by far the largest minable andalusite deposits of the world, estimated at some 70 Mt of known in situ reserves. The only other large commercial production of andalusite comes from France, with known reserves of about 5 Mt. Potential new deposits are known from China, Ireland, Australia, and South America. World consumption of andalusite in special performance refractories has risen from less than 10 ktpy in 1960 to nearly 300 ktpy in 1990, which is due to cost effectiveness in many industrial applications compared to other conventional refractory products. Andalusite-based refractories have traditionally been used in Europe, South Africa, and the Far East; usage in America was limited in the past due to relatively high delivery costs and availability of other local refractory minerals. However, there is a significant trend towards greater use of andalusite in North America, thus opening new markets and replacing other traditional refractory raw materials. GEOLOGY Andalusite occurs in metamorphosed rocks of clay-like com- position, as in the andalusite-hornfelses in thermal aureoles (contact metamorphism), formed under conditions of high temperatures and low stress, and in regional metamorphic rocks, such as the andalusite-schists. These schists are mostly unconnected with definite igneous intrusions but were presumably also formed at high temperatures and under low stress. Andalusite can also appear in alluvial deposits associated with the primary deposits. At depths of 10 to 20 km, temperatures of up to 450°C might be expected. Another result of increasing depth is an increase of pressure due to the load of the rock cover. The load stresses involved in metamorphism is generally believed to lie in the range 0 to 10 000 bars. During contact metamorphism the increase in temperature is brought about by the injection of magma. The temperature reached in the country rock at some distance from the igneous body will always be less than the initial temperature of the intrusion, which is presumably less than 1 200°C, and will vary with time and distance from the contact. A simple metamorphic reaction involving dehydration of an aluminous sediment can be: [ ] At higher temperatures sillimanite would form at the expense of andalusite, while kyanite would be the mineral formed at higher pressures, as can be seen in the phase diagram of A12Si05 (Fig. 2).

Jan 1, 1994

By R. A. Allwes

In-plane bending and torsion tests were conducted on full-scale masonry walls to evaluate three post-reinforcement designs. The designs were developed to minimize longwall mine subsidence damage to existing residential masonry foundations. The bending tests show that vertical and horizontal post tensioned tendons significantly increase the resistance of a masonry wall' to in-plane bending. The torsion tests reveal that post tensioned tendons increase a masonry wall's limit of deformation but do not increase its torsional stiffness. The torsion tests also show that the masonry units minimally contribute to the torsional stiffness of a masonry wall.

Jan 1, 1995

By F. S. Knoll

Electrostatic separation is one of the most misunderstood physical processes used to beneficiate minerals. Nonetheless, millions of tons of titanium ores, iron ores and other minerals are processed every year economically, efficiently and safely. Over the past ten years major advances in electrostatic separation and its application have occurred. New processes include dewatering clay slurries, separating halite and sylvite, and shape separation of vermiculite and gangue minerals. Electrostatic separation techniques are based on one of two methods, electrophoresis or dieleccrophoresis -- processes involving charged and uncharged particles respectively. In some cases, the combination of these two techniques has proven quite useful. The purpose of this paper is to provide a basic understanding of the physical processes collectively called "electro- static separation" in order to enhance one's ability to define and consider new possibilities in mineral processing and other fields.

Jan 1, 1984

By Maurice L. Madden

An investigation was undertaken for a ground water discharge plan for the Chino mining complex near Hurley, New Mexico. Operations which impact ground water include dump leaching, storage reservoirs, and tailings seepage. The investigation included both hydrogeological data collection and laboratory analysis. A conceptual understanding of surface water and ground water was then developed. Surface water and ground water models were used to match existing conditions and predict the impact of operational modifications. The study concluded that runoff and resulting leach reservoir overflows were primarily responsible for the ground water degradation. Tailings seepage represents a smaller part of the impact.

Jan 1, 1984

By I. J. Lin

The effect of various types of structural modification on the critical micelle concentrations (CMC) and hydrophile lipophile balances (HLB) of certain surfactants has been considered. Using the concept of effective chain length for the substituted species, an index of hydrophobicity (I) has been defined. It is hoped that such an index will allow one to choose surfactants for particular purposes in a less arbitrary fashion than heretofore.

Jan 1, 1973

By J. P. McKinney

A mathematical model is presented for the electrokinetic dewatering of suspensions of phosphatic clays. The modeling approach couples a boundary-element model for solution of Laplace?s equation to a recently developed constitutive equation that relates the change in solids content with applied electric field and time. The observation that the electric field controls both the maximum solids content achievable and the time required to reach that value is shown to severely constrain the application of electrokinetic dewatering strategies to an entire clay settling area. The approach, however, may be feasible for implementation as part of a continuous plant process.

Jan 1, 2011

By C. B. Rash, W. W. Fowler, Gill Montgomery

INTRODUCTION Fluorspar is the common term used for the mineral fluorite, which is naturally occurring calcium fluoride (CaF2). It is the principal source of fluorine, the most reactive of the chemical elements, from which a great variety of unique and strategically important chemicals are produced. Commercial deposits of fluorspar are widespread throughout the world, and its availability is essential to the industrial progress of all nations. GEOLOGY AND MINERALOGY In its pure form fluorspar, CaF2, contains 51.1% calcium and 48.9% fluorine, and has a sp gr of 3.18 and a hardness of 4. It is commonly a glassy mineral. colorless, white, or grayish. but may also be various shades of purple, pink, blue, green, yellow, or tan. It belongs to the cubic system mineralogically, and commonly crystallizes into cubic shapes in vugs and cavities, although most of it is massive, with interlocking crystals. Minable fluorspar deposits, in descending order of importance, occur as bedded limestone replacement deposits along fault zones; fissure-filling vein deposits; breccia filling in limestones, dolomites,

Jan 1, 1985

By Daniel A. Wasson

A review of the history of boosters is given with examples of the prominent types that have been made commercially. The performance and design features of protected core boosters are discussed in detail. A new gel booster is discussed with its advantages to the mining industry. Booster size, hole configuration, performance and safety aspects are reviewed. Important features of boostering in above ground and underground blasting are related to an economic analysis. This presentation will cover different types of boosters commonly used in mining. However, for the purpose of this paper a few terms need to be defined to clarify the action of different parts of a priming system. Booster* - "Any unit of explosive or blasting agent to be used in a charged hole for the purpose of perpetuating or intensifying the initial detonation". Primer* - "A unit, package or cartridge' of explosives containing a detonator or detonating cord which is used to transmit detonation to other explosives or blasting agents". Detonator - A device for initiating a detonation from a flame or a small electric current, the former being represented by a fuse cap and the latter an electric blasting cap.

Jan 1, 1981

By John F. Shea

When Dick Robbins asked me to give a keynote address, I felt it might be in order to review some of the practices and techniques used in tunneling and work up to some of the concepts now used to mine and construct tunnels. Needless to say, there have been many changes in tunneling technology and also many changes in the Safety Codes controling them. An example of this latter change was the fact that in 1931, my father excavated the Owyhee Tunnel No.5 with gas locomotives. He was able to do it because there was no natural gas in the rock and the ventilation system was designed to free the tunnel atmosphere from powder and exhaust fumes. Today OSHA rules would never permit gas locomotives underground, although there were no incidents on this particular project. One of my first tunnels, as Project Manager, was the Clear Creek Tunnel for the Bureau of Reclamation. Our method of handling muck was the Conway Muckers. This unit was a valuable improvement to the hand mucking of previous generations. The Conway was also used in our Navajo Project, in New Mexico. Unlike the Clear Creek project, where water was one of our main problems - up to 7,200 gallons per minute, at a pressure of 395 pounds per square inch - in the Navajo Tunnel, we had a mixed face which caused a major problem with our support system. In one of the Navajo Tunnels, there was a major cave-in, when the squeezing shale came in during an attempt to strengthen the support system. Although moving shale was not a constant problem, there were areas where the shale was five to six feet above the spring line.

Jan 1, 1976

By Y. Guan

The dissolution behavior of copper and gold from their pure state and from Au/Cu alloys in cyanide solutions has been investigated using a rotating disc. Oxygen was used as an oxidant. The effect of the composition of the alloys, stirring speed of the disc, concentration of lixiviants and temperature on the overall dissolution kinetics has been studied. Gold/copper alloys of three compositions were used in this study. The atomic percent of gold in these alloys was 75, 50 and 25, respectively. The dissolution behavior of these three alloys was compared with that of pure gold and of copper under the same chemical conditions. In general, the dissolution of copper and gold from alloys is partially controlled by surface chemical reaction and largely by mass transfer.

Jan 1, 1992

By Jan Reimann

Increasing individualization with smaller quantities, growing competition from low-wage countries, and the continuous drive towards digitalization are the challenges that industrial companies in high-wage countries must face. The example of the Flender One gearbox modular system demonstrates how consistent standardization and digitalization are the enablers for AI, and thus already enable new business models and business approaches today.

Feb 22, 2026

By M. Karmis

Promoting a strong safety culture requires that the significance of unsafe acts be emphasized. This can be achieved vividly by accurate recreation of unsafe actions in the workplace, demonstrating explicitly how they resulted in a fatality or significant injury. Visual reconstructions of incidents can be realized today on personal computers. The approach described in this paper uses readily available PC software and hardware and results in output that can be presented to the intended audience using a variety of delivery methods. An actual incident involving a surface mining operation is reconstructed using Virtual Reality techniques. Use of the visualization approach to accident reconstruction as a training tool is discussed.

Jan 1, 2003

Laboratory testing by the Federal Bureau of Mines has shown that the removal of insoluble slimes using selective flocculation and flotation is a viable method for treating low-grade potash ores which have a high content of water-insoluble impurities. Results indicated that up to 85 percent of the insoluble slimes could be removed from sylvinite ore containing 5 percent water insolubles and 13 percent K20 using nonionic or cationic polyacrylamide flocculants and cationic, anionic, and/or nonionic collectors. Subsequent potash flotation recovered up to 88 percent of the potash in rougher concentrates containing 47 to 57 percent K20. Sizing and cleaner flotation of the rougher concentrates upgraded the products to 60 percent K20. Filtration of the insoluble slimes flotation concentrates recovered 87 to 0 percent of the brine. Flotation concentrate filtration rates were 7 times faster than the filtration rates of mechanically deslimed products.

Jan 1, 1977

The properties of interfacial water at hydrophilic surfaces are of great importance in many technological areas including flotation, solid-liquid separation, dispersion and emulsions, flocculation, adsorption, corrosion, and soil contamination. This paper examines the use of FTIR/internal reflection spectroscopy (FTIR/IRS) to study the spectral characteristics of interfacial water at silica surfaces. FTIR spectra were characterized by consideration of the OH stretching region (3000-3800 cm-1) associated with the vibrational spectra of interfacial water. The broad peak in this region was deconvoluted in order to isolate overlapping spectral features that describe the nature of hydrogen bonding in interfacial water. Three distinct bands were found; -3600 cm-1 (free OH), -3400 cm-1 (incomplete tetrahedral coordination), and -3240 cm-1 (complete tetrahedral coordination) and the variation of their intensities with pH was found to be significant. This spectral information helps to explain orientation and bond ordering of interfacial water molecules at hydrophilic surfaces.

Jan 1, 1998

By G. R. Brunskill

The molybdenite flotation plant at Magma Copper Company, San Manuel concentrator has been in operation since 1956. In January of 1980 the plant was converted from a hydrogen peroxide - ferrocyanide process to the current sodium cyanide - sodium hydrosulfide process. This paper is an operational review of Magma Copper Company's molybdenite recovery circuit, column cell flotation experience and use of on- stream x-ray flourescence analysis.

Jan 1, 1985

By Ron Robinson, Trevor Harrison

The planning, installation and commissioning of the first scheme of controlled recirculation of air flow in a section of coal mine in Great Britain is described, together with the proposals for a second installation. The work updates a previous paper (Robinson and Harrison, l986) on the subject. The special problems of ventilating the increasingly distant faces of the undersea mines in the North East Area of the British Coal Corporation are discussed and the alternative solutions stated. The advantages of using a system of controlled recirculation of air are proposed together with the safety features considered necessary. Design and installation details of the recirculation fans and a new booster fan are described.

Jan 1, 1987

By Mark Gershon

Most recent work in the field of mine production scheduling has focused on either the computerization of the traditional methods or the development of sophisticated mathematical optimization models. Yet it is clear to all concerned that the optimizers need to be made more practical and the traditional approach needs to be made more optimal. This paper, along with another recent paper (Gershon, 85) open a middle ground between these two approaches. In that recent paper, a heuristic procedure for production scheduling was introduced. Here, a series of short term optimizations are used in a creative manner to approximate the true long term optimization. Since these small optimizations are aimed at blending to meet production quality specifications, this approach is most applicable to commodities where the blending function is very important such as coal, cement, phosphates or iron, to name a few. The traditional and the optimization approaches are so far apart that their' advocates have difficulty identifying with the other approach. This is especially true concerning the difficulty of understanding the optimization models for those not trained in the field of operations research. This paper takes the position that the pro- 120 per role of the operations researcher is to provide not only useful and advantageous approaches, but practical, understandable and implementable ones as well. This is the goal of the paper in describing a new approach, consistent with the traditional methods and aimed at approximating the results of the optimizers.

Jan 1, 1986

By Alistair James, Mo Shahsavari, Leon Botham

The 1889 Johnstown Flood, which killed 2,209 people, was a preventable disaster stemming from systemic decisionmaking failures. This paper applies modern Risk-Informed Decision Making (RIDM) frameworks to analyze the historical context and explore alternative outcomes through hypothetical multiverse scenarios. By reconstructing the risk landscape of the South Fork Dam, we demonstrate how structured hazard identification, risk assessment, and stakeholder communication could have mitigated or prevented the catastrophe. Three counterfactual scenarios—proactive maintenance, community engagement, and regulatory oversight—are evaluated to quantify potential lives saved and economic benefits. The study acknowledges historical barriers, including technological limitations, lack of governance, and socioeconomic disparities, which constrained risk-aware decisions in the 19th century. The analysis draws critical parallels to contemporary engineering challenges, particularly in tailings storage facility (TSF) management, where similar risk blind spots persist. The paper concludes that RIDM is not merely a technical tool but a governance imperative, essential for ethical and sustainable engineering practice. By learning from historical near-misses and failures, the modern engineering community can strengthen resilience and accountability. This work contributes to the growing body of retrospective risk analysis, offering a methodological framework for applying RIDM to historical disasters to inform future safety standards.

Feb 22, 2026