The Economic Value of Industrial Minerals and Rocks for Developing Countries: A Discussion of Key Issues

This paper provides a few general comments on the nature and economic value of industrial minerals and rocks and the need for an increased exploitation and use of these materials in developing countries. These materials are of great economic value as main raw materials for the construction, glass, abrasive, paper, chemical, ceramics, metallurgical and agricultural industries. Developing countries dispose of many of these materials, and could derive greater economic benefits from them. Per capita consumption of industrial mineral products continues to grow in developed countries and part of this demand could be met by exports from developing countries. The paper describes some of the issues to be addressed and steps to be taken if developing countries are to gain from industrial minerals and rocksEconomic value industrial minerals and rocks; consumption industrial minerals and rocks; production industrial minerals and rocks; developing countries benefit minerals and roc

The Economic Value of Industrial Minerals and Rocks for Developing Countries: A Discussion of Key Issues

This paper provides a few general comments on the nature and economic value of industrial minerals and rocks and the need for an increased exploitation and use of these materials in developing countries. These materials are of great economic value as main raw materials for the construction, glass, abrasive, paper, chemical, ceramics, metallurgical and agricultural industries. Developing countries dispose of many of these materials, and could derive greater economic benefits from them. Per capita consumption of industrial mineral products continues to grow in developed countries and part of this demand could be met by exports from developing countries. The paper describes some of the issues to be addressed and steps to be taken if developing countries are to gain from industrial minerals and rock

The Economic Value of Industrial Minerals and Rocks for Developing Countries: A Discussion of Key Issues

This paper provides a few general comments on the nature and economic value of industrial minerals and rocks and the need for an increased exploitation and use of these materials in developing countries. These materials are of great economic value as main raw materials for the construction, glass, abrasive, paper, chemical, ceramics, metallurgical and agricultural industries. Developing countries dispose of many of these materials, and could derive greater economic benefits from them. Per capita consumption of industrial mineral products continues to grow in developed countries and part of this demand could be met by exports from developing countries. The paper describes some of the issues to be addressed and steps to be taken if developing countries are to gain from industrial minerals and rock

Does increasing treatment frequency address sub-optimal responses to ivermectin for the control and elimination of river blindness?

Background Several African countries have adopted a biannual ivermectin distribution strategy in some foci to control and eliminate onchocerciasis. In 2010, the Ghana Health Service started biannual distribution to combat transmission hotspots and sub-optimal responses to treatment. We assessed the epidemiological impact of the first 3 years of this strategy and quantified responses to ivermectin over two consecutive rounds of treatment in 10 sentinel communities. Methods We evaluated Onchocerca volvulus microfilarial intensity and prevalence in those aged +/-20 years before the first, second and fifth (or sixth) biannual treatment rounds using skin snip data from 956 participants. We used longitudinal regression modelling to estimate rates of microfilarial repopulation of the skin in a cohort of 217 participants who were followed-up over the first two rounds of biannual treatment. Results Biannual treatment has had a positive impact, with substantial reductions in infection intensity after 4 or 5 rounds in most communities. We identified three communities—all having been previously recognised as responding sub-optimally to ivermectin—with statistically significantly high microfilarial repopulation rates. We did not find any clear association between microfilarial repopulation rate and the number of years of prior intervention, coverage, or the community level of infection. Conclusions The strategy of biannual ivermectin treatment in Ghana has reduced O. volvulus microfilarial intensity and prevalence, but sub-optimal responses to treatment remain evident in a number of previously and consistently implicated communities. Whether increasing the frequency of treatment will be sufficient to meet the World Health Organization’s 2020 elimination goals remains uncertain

An exploration-adjusted mineral occurrence model.

A mathematical model describing the probability for n mines or prospects occurring within an elementary unit (cell) of an area has been referred to as an occurrence model. Estimation of parameters of occurrence models has been plagued by the effect of area delineation on the parameters. Moreover, incompleteness of exploration creates a bias in parameter estimates. This study proposes that when the model is to describe the probability for occurrence of mines or prospects, the appropriate area is a metallogenic unit of mining district scale. Accordingly, this study examined the delineation of area by successive expansion of a polygon seeking that size of area which provides the best fitting of a truncated and effort-adjusted exponential model. However, estimation of occurrence model parameters was found to be sensitive to location of polygon on the cluster. Consequently, this approach was abandoned in favour of geologically-defined metallogenic units referred to as Intrinsic Samples. Truncated and effort adjusted occurrence models were fitted to Intrinsic Samples which included the mining districts of the Walker Lake Quadrangle of Nevada and California. The estimated model for each metallogenic unit is used to estimate the gold-silver metal endowment of the unit. This represents a departure from previous studies, e.g. Allais, in which a single parameter estimate from a control area is used to estimate the mineral endowment in all parts of a large study area. Furthermore, the study addresses the issue of economic truncation of occurrence data used in exponential model construction. Because a metallogenic unit is less than completely explored, estimated parameters based on observed occurrences provide a biased description of the number of occurrences present (i.e. endowment). The transition from sample to endowment (population) parameter is achieved by parameterizing the exponential model for a metallogenic unit on exploration effort deployed in a unit area. Thus, fitting the model to observed data and evaluating it at infinite effort yields the model for gold and silver metal endowment in a metallogenic unit