Barbara Winifred Murck

Sustainable development in the mining industry: clarifying the corporate perspective

Abstract This paper examines sustainable development in the corporate mining context, and provides some guidelines for mining companies seeking to operate more sustainably. There is now a burgeoning literature that examines sustainable development in the context of minerals and mining, most of which is concerned with sustainability at global and national scales. What is often challenging to ascertain, however, from these numerous perspectives on sustainable mineral extraction, minerals and metals recycling, environmental management, and social performance, is how sustainable development applies to mining companies themselves, and what steps a mine must take in order to improve the sustainability of operations. Since mining processes have the potential to impact a diverse group of environmental entities, and are of interest to a wide range of stakeholder groups, there is ample opportunity for the industry to operate more sustainably. Specifically, with improved planning, implementation of sound environmental management tools and cleaner technologies, extended social responsibility to stakeholder groups, the formation of sustainability partnerships, and improved training, a mine can improve performance in both the environmental and socioeconomic arenas, and thus contribute enormously to sustainable development at the mine level.

The effects of temperature, oxygen fugacity and melt composition on the behaviour of chromium in basic and ultrabasic melts

Chromite was equilibrated with two natural basic liquids and one natural ultrabasic liquid at temperatures and oxygen fugacities appropriate to geological conditions. The experiments were designed to document changes in mineral and glass compositions between the iron-wustite and nickel-nickel oxide buffers, with special emphasis on conditions along quartz-fayalite-magnetite. The Cr contents of the melts at chromite saturation increase strongly with increasing temperature and with decreasing oxygen fugacity. A relationship is described which accounts for the compositional dependence of the partitioning of Cr between spinels and silicate melts by considering the exchange of FeCr2O4 component between the crystalline and melt phases. Interpretation of the data in terms of this exchange suggests that Cr3+ in metaluminous melts occurs in octahedrally coordinated sites, and that it does not depend on charge-balancing by monovalent cations. In this model, Cr3+ is proposed to behave like network-modifying Al3+ and Fe3+, i.e., the excess aluminum and ferric iron which do not participate in tetrahedrally coordinated matrix or network-forming complexes. The results can also be applied to the problem of the formation of massive chromitites of great lateral extent in basic layered intrusions. The data are consistent with a model in which the crystallization of chromite is initiated through magma mixing, in combination with the rapid heat loss associated with periodic influxes of magma into a chamber. An alternative model, in which chromite crystallization is initiated by repeated fluctuations in oxygen fugacity, is possible only if the magma fO2 is not controlled by an oxygen buffer such as QFM.

Progress toward pollution prevention and waste minimization in the North American gold mining industry

Abstract This paper presents a case study of pollution prevention and waste minimization in the North American gold mining industry. Specifically outlined are: 1) the environmental options available to North American goldmines for use in cyanidation setups and Acid Mine Drainage (AMD) control, generally recognized as the two most environmentally problematic areas in the industry; 2) the progress made towards pollution prevention and waste minimization in each of these industrial areas; and 3) operational areas in need of further environmental improvement. Analysis of selected data and questionnaire feedback indicates that most of the gold mines operated by the larger Senior Mining companies have implemented the state-of-the-art measures that best prevent environmental problems in cyanidation practices and AMD setups, but that the remaining operations, which are owned by small- and medium-sized Junior Mining companies, lag far behind, and are only doing what is necessary to comply with environmental regulations. Senior Mining Companies clearly have the research, technologic, and financial resources to design and implement effective environmental management practices at properties. Communications with the managers from Junior Mining Operations, however, reveal that a number of barriers, which are economic and legislative in nature, are preventing implementation of the leading edge environmental technologies needed to minimize problems with pollution and wastes. It is concluded that perpetuating a uniform pattern of pollution prevention and waste minimization in the industry will require the complete removal of these barriers, the North American gold mining industry to form research partnerships with governments and academic institutions, and a number of largely unexplored environmental aspects of the industry to be heavily researched and improved, in particular, biological oxidation.

Simulation of a policy aimed at the reduction of wood use in the Sudan

A rectangular economic input-output table for the Sudan is presented, based on nine sectors, thirty-seven commodities, six primary inputs, and seven final demand categories. Four possible models of intermediate consumption are derived by using linear programming and entropy maximizing. The table is then linked to a coefficient representing wood use per unit of output in the Sudanese economy. A policy aimed at a reduction in wood use is tested by simulating the introduction of more efficient charcoal stoves into urban households. Implementation of the policy would lead to a significant reduction in total wood used, from 88 km2 to 194 km2 per year, depending on which of the four models for intermediate consumption is utilized. Reallocation of the resulting savings by households into energyintensive commodities, however, reduces the effectiveness of the policy by as much as 48%.

Promoting and Evaluating Participation in High-Enrollment Undergraduate Courses

A particular challenge for instructors of high-enrollment (200+ students) classes is to encourage students to attend class regularly and to participate actively in learning. An adaptable form of “Participation Day” exercise which has been used successfully in large classes is the “One-Minute Essay,” in which students are given one minute to write down something they have learned in class that day. One-Minute Essays encourage attendance, active participation, and mental involvement in course material, and they enhance contact between instructor and students. Ideally, Participation Day exercises should represent a component of the course mark. They also must be manageable in terms of required class time for the activity; require a minimum amount of marking time; be generally adaptable to very large class sizes; involve writing, if possible; and encourage students to interact with one another.