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By A. M. Taweel, M. T. Ityokumbul, A. I. A. Salama, M. W. Mikhail

The liquid-phase mixing within CANMET's Western Research Centre's (WRC) 0.76-m-diem pilot-plant flotation column was characterized using a salt tracer. The process variables studied were frother addition and, gas and liquid flow rates. The response of the column to a tracer pulse was monitored at three axial and two radial locations. The results showed that the 2-tph flotation column was well mixed. Discussed are the implications of this observation to column design and scale-up.

Jan 1, 1996

By S. K. Kawatra, S. J. Ripke

Finely disseminated iron ores compose much of today's reserves. After removing the silicate gangue, the resulting fine iron oxide concentrates require pelletization with a binder to enable transportation and reduction. Binders can be used more efficiently if their binding mechanisms can be completely understood. Typically, bentonite clay is needed as a binder to improve the strength of the pellets. Bentonite is an effective binder at a relatively low cost, but costs could be reduced further by replacing bentonite with even lower-cost binders, such as high-carbon Fly-Ash Based Binder (FBB). In this study, it was found that bentonite binds by a physical mechanism, while FBB binds by a chemical mechanism. These mechanisms were determined to be incompatible. Partial replacement of either binder with the other reduced dry magnetite pellet compressive strengths below the industrially acceptable value of 22.2 newtons (5 lbf). Activators and accelerators that activated the fly-ash deactivated the bentonite. The incompatibility of these two binders is explained.

Jan 1, 2000

By D. R. McGregor, B. V. Clingan

A practical application of recent design concepts makes it possible to design a column cell to fit a specific set of conditions. The design and operating parameters of a column cell installation that replaced a conventional two-stage copper flotation cleaning circuit at Magma Copper Co., San Manuel, AZ, using these design concepts is described. A survey of other mineral processors using column cell technology was conducted. The results of this survey are also discussed.

Jan 1, 1988

By Raimondo Ciccu, Francesco Satta, Marcello Ghiani, Piero Carbini

Nonpolar oils are utilized as collectors in low-rank coals flotation processes. The analysis of the mechanism of the hydrophobic film formation on coal particles permits the identification of the main characteristics that these reagents should exhibit in order to render the process technically and economically efficient. Such requirements - low repulsive energy developed in the interaction with coal particles; limited interfacial tension at the coal-oil boundary; relatively low viscosity and, at the sake time, poor ability to absorb into the coal pores - are found in some binary mixtures of oils having different volumic mass. The features of such mixtures as well as the advantages deriving from their use for the flotation of a Sulcis coal sample and experimentally proven, are described.

Jan 1, 1989

The modelling process described in this paper was developed in order to assess the feasibility of various investments options for the exploitation of a lignite deposit located in the Prefecture of Florina, Greece. The model uses as evaluation criterion the net present value. It is based on the characteristics of the reserves and relates the decision making with numerous technical, economic and environmental factors. The examined alternatives include the construction of a new thermal power plant at the mine-mouth, the fuel supply of already existing power plants located at relatively long distances and the fuel exports in neighboring countries. Moreover, the feasibility of post-poning the exploitation of the lignite deposit and preserving its reserves for exploitation in the future is also assessed. The paper also includes a short discussion about the environmental constraints related to the supply of lignite produced from Florina mines to power plants that were designed and constructed for burning fuel mixtures with different quality characteristics.

Jan 1, 2005

By S. K. Kawatra, A. K. Bakshi

An on-line rheometer was developed to monitor the slurry rheology of a thickener underflow. The thickener processed a chalcopyrite flotation concentrate having a top particle size of 125 µm and a solids content of 30% to 60% (by weight). The slurry also contained residual flotation reagents, resulting in hydrophobic particles. Polymeric flocculants and lime were added to the thickener to flocculate the particles. Using the on-line rheometer, the slurry was found to exhibit pseudoplastic behavior with no yield value. It was also determined that factors other than the percent solids were responsible for changes in the slurry rheology.

Jan 1, 1999

By G. Belardi, N. Sheau, P. Plescia, F. Veglio

A study was conducted to assess a new wet gravity-separation machine, identified as the Multi-Gravity Separator(MGS). Chromite fines, obained from an Albanian chromite and olivine ore and containing 23% Cr2O3 and 18% SiO2, were used in the study. The first step was to determine the influence of various operating parameters. The study indicated that the most important variables for the MGS are rotational speed, tilt angle and shake amplitude. The best treatment conditions for the ore were then identified by investigating a series of circuits designed to produce a marketable product. In open circuit, a concentrate containing 50% CI-203 was obtained with a recovery of 72%.

Jan 1, 1996

By G. Wang

Industrial minerals processing has gained importance lately, not only due to its wide range of new and regular applications in processing different industrial minerals, but also due to the strict specs under which products are commercialized. Among the processes applied to industrial minerals, flotation is a leading technology. The laboratory study and commercial operation demonstrate that the sulfonated reagents are very effective collectors for industrial minerals. This paper compares synthetic petroleum sulfonate with fatty acid on iron reduction in glass sand processing and describes the effect of conditioning pH on iron reduction using synthetic petroleum sulfonate as collector, the effect of molecular weight of natural and synthetic petroleum sulfonates on their flotation performance and the enhancement made for certain products.

Jan 1, 2011

By Pieter C. van Aswegen, J. A. Brierley, C. L. Brierley

The bacterial-oxidation (BIOX®) process for the pre-treatment of refractory ores for gold recovery is marketed by BlOMlN Technologies S.A. The process was originally developed by GENMIN who is still providing testwork, design and commissioning assistance to BIOMIN. Since 1986 three BIOX® plants have been commissioned by GENMIN. A further two plants will be commissioned during 1993 and 1994. The commissioning and operational experiences from these plants are described in the paper.

Jan 1, 1993

By Colin C. Harris, Jie Zheng, P. Sornasundaran

Powder surface and polymer structural changes during stirred milling have been studied as a function of grinding time, solid concentration and polymer molecular weight. It was found that specific surface area of limestone particles can be increased over 100% by using polymer additives. Particle surface and polymer structure were also found to change during grinding. Powder surface and polymer properties have been determined using Surface Tension, Fluorescence, TOC and HPLC/GPC analysis, and surface and polymer properties are correlated with operating variables and the mechanisms involved are explored. Particularly, the fragmentation of the polymer molecules was found to occur during long term grinding and this was beneficial for ultrafine grinding.

Jan 1, 1998

By M. Abdi Oskouei

Some believe that Sustainable Mining due to impermanence of mining operation and adverse environmental impacts of mining, is an oxymoronTruly, no one can overlook these environmental impacts; however, a sustainable development is based on three elements Environmental, economical and social sustainability. In order to assess the relation between mining activities and sustainable development, not only environmental but also economical and social sustainability must be considered.Thanks to mine reclamation the adverse impact of mining on the environment can be reduced, meanwhile it will improve the social and economical condition after the mine-closureTo ensure that a mining operation is toward sustainable development goals, specific criteria and indicator frameworks have been established, in addition, for verification of our discussion the suitable selected reclamation plan for Bibishahrbanoo limestone mine of Tehran-Iran and its effect on sustainability of region has been studied.

Jan 1, 2011

By V. Rajaram, D. P. O’Connor, L. Sakamoto

In 1988, the Metropolitan Water Reclamation District of Greater Chicago (MWRD) imposed a no-blasting specification (blasting is restricted to the construction shaft and shaft bottom or boot) on the Deep Tunnel project. This was prompted by numerous complaints from residents in the vicinity of the project and controversies experienced on previous projects from blasting the rock overlying the tunnel. This paper will describe the methods used by two major contractors driving 20 km (12.5 miles) of tunnel, and drilling more than 36 shafts under this restrictive specification. The impacts are detailed on design, construction, schedule, cost and the environment.

Jan 1, 1993

By W. W. Roepke, B. D. Hanson

A major problem facing the coal mining industry today is the need to meet more stringent dust standards due to quartz. When secondary suppress ion is not adequate, the time-consuming and costly cut-and-try method of modifying the mining machine is used in the hope that it will reduce dust generation. The Coal Cutting Technology Group, at the Bureau of Mines' Twin Cities Research Center, has developed an inter-active computer program for drum- type cutting systems to help identify, in advance, modifications that offer the best potential for reducing dust. The program, Relative Dustiness Indicator (REDI), evaluates machine dimensions, seam characteristics, and operator-controllable variables for dust generaton, energy, forces, and product ion.

Jan 1, 1986

By P. W. Hunter

The construction of a major sewerage scheme requiring 15.3 km of 5.5m excavated diameter tunnel in basalt, mixed and soft ground has been undertaken by the Melbourne and Metropolitan Board of Works. A double shielded Tunnel Boring Machine was selected to excavate 13.7 km of basalt and mixed ground. Advanced methods for recording operational data on the TBM were introduced. Progress to date has shown that the TBM can excavate rock very effectively with a best weekly production of 178.8m; soft ground has been encountered and successfully handled.

Jan 1, 1987

By V. A. Khartcenko

As the environment conditions deteriorate with the intensification of mining, the problems of mineral resources protection and the development and introduction of various bio- technologies are becoming more pressing This paper is devoted to the description of an ecological simulation system, related to the exploitation of a mine in a given region. We suggest mathematical tools for solving the main problem, namely an expert system, providing the simulation of ecological models for the mining complex. On the basis of the suggested models, algorithms, and software facilities, numerical modeling was carried out, as well as systematic investigation and processing of the mining activities of the complex. AS a result of this work we have obtained more effective parameters of technological and economical measures of environmental protection.

Jan 1, 1992

By James P. Morris, William H. Hansmire

The U. S. Department of Energy's (DOE) Yucca Mountain Project (YMP) is a scientific endeavor to determine the suitability of Yucca Mountain for the first long term, high level nuclear waste repository in the United States. The status of this long-term project from the construction perspective is described. A key element is construction of the Exploratory Studies Facility (ESF), which is being excavated with a 7.6 m (25 ft) diameter tunnel boring machine (TBM). Development of the ESF may include the excavation of over 15 km (9.3 mi) of tunnel varying in size from 3 to 7.6 m (10 to 25 ft). Prior to construction, extensive constructibility reviews were an interactive part of the final design. The intent was to establish a constructible design that met the long-term stability requirements for radiological safety of a future repository while maintaining flexibility for the scientific investigations and acceptable tunneling productivity.

Jan 1, 1995

By Gordon E. Ager

A technique for the synthesis of mineral processing flowsheets from laboratory batch test data is described and examples of the application of the procedure are given. The procedure requires the collection of kinetic data, the optimization of the flotation time in each separation stage, then simulation of the material balance for a continuous circuit.

Jan 1, 1989

By Fathi Habashi

At the Duisburger Kupferhütte plant in Germany, pyrite cinder is collected from the sulfuric acid manufacturers in that country and processed to recover the nonferrous metals contained in the cinder, before charging it to the blast furnace for iron recovery. A typical analysis of the cinder is given in Table 9-1. The pyrite cinder is mixed with NaCl and treated continuously in a multiple hearth furnace. The evolved gases are scrubbed with water to form a weak acid which is used for the leaching process. Each batch requires about 2 days for leaching. The concentrated leaching solution obtained in the first 15 to 20 hr is sent for copper recovery, while that subsequently obtained, being poor ill metal content, is recycled. The residue, called purple ore, now a high-grade iron ore (61-63 % Fe); is sintered and delivered to the blast furnace.

Jan 1, 1970

By Paul D. Tomlingson

Will Rogers unwittingly commented on the essence of evaluations when he said: "We don't know what they don't know!" In so doing, he explained why managers have an obligation to verify that their personnel really know what is expected of them. Rogers further stated that "What we know may not be so!" Here, he suggests that managers must establish the correctness of facts on which they make decisions concerning the future of their organizations. Yet, there are some managers who may not have considered this basic wisdom. These are perhaps the ones who shun a solid, fact-finding evaluation. Instead, they trust to guesswork as a basis for attempting improvement. Without realizing it, they may be making incorrect decisions harmful to the very organization they are trying to improve. Unfortunately, an attitude of avoiding evaluations often permeates whole organizations when their managers fail to appreciate their importance. Recently, the following was found prominently displayed in the office of a maintenance manager. Regrettably, the facts of a subsequent evaluation established how imprudent his attitude was:

Jan 1, 1991

By D. F. Martin

Sustainability is typically understood as having three interrelated dimensions-environmental, economic, and social. However, far less attention has been paid to social sustainability than to the other two forms. The paper argues that one of the difficulties in giving substance to the concept of social sustainability is that it is inherently value-dependent and has major conceptual, definitional and therefore measurement issues. This is particularly the case in complex crosscultural environments such as those found in Australian mine hinterlands with significant Aboriginal populations. Nonetheless, a concept of social sustainability can provide an important counter to the usual focus on environmental and economic sustainability, and can productively guide the minerals industry in its engagement with the Aboriginal people of mine hinterlands. The paper outlines a set of principles for socially sustainable communities, and proposes means by which these principles can be implemented. It further suggests that these principles may have broader applicability than just in the case of Aboriginal people.

Jan 1, 2005