Quantitative determination of modal content and morphological properties of coal sulphides by digital image analysis as a tool to check their flotation behaviour

An efficient depression of coal sulphides in the flotation process means a healthier environment and may be essential for the sustainability of a coal operation. Nitric and ferric oxidative pre-treatment of coal pyrite have been tested to improve pyrite depression, and the results are compared with those from the process of raw, not pre-treated coal. The removal indexes point to nitric pre-treatment as the best, but depression is still low. The microscopic study of feed and products, coupled to Digital Image Analysis (DIA) in all the cases, provide important clues to understand the behaviour of pyrite, which can be related to quantitative parameters, such as the exposition ratio (ER), and to qualified interpretation of the textures. Pyrite shows in the first float an unexpected hydrophobic behaviour, which is due to its occurrence as framboids, or porous particles which may be intergrown with organic matter and behave as coal. In general, the flotation results can be predicted from the DIA-data, e.g. depression of liberated pyrite into the tailings, increased by oxidative pre-treatments by 300% (ferric) or by > 400% (nitric); or concentration of middlings with lower pyrite ER in the floats. DIA is an efficient tool to obtain some important quantitative informations which otherwise would be inaccessible (e.g. the morphological data on > 1,000,000 pyrite particles for this study), and its use should be enhanced to check ore processing

Water harvesting and better cropping systems for the benefit of small farmers in watersheds of the East India Plateau

This paper discusses an integrated approach for water resource management to improve rural livelihoods in the East India Plateau. This has involved linking hydrological, agronomic and social aspects to increase access to water, improve water use efficiency and develop capacity within the villages for better decision making regarding use of the available resources. To this end, the research adopted a participatory, action-learning approach, with villagers joining in developing research questions, executing experiments, collecting data and sharing in their interpretation, as well as planning intervention work designed to improve access to water, particularly in the early dry season. The focus of this paper is on the integration of the different aspects of water resource management, with particular emphasis on the social issues. This included working with women's self-help groups and village watershed committees, and specific efforts to engage women in research and related development activities. The result has been an improved capacity within the village for managing water resources, including improved self-perceptions as farmers (especially women), better understanding of the potential resources and any constraints (e.g. soil fertility) and knowledge of how to manage the constraints (e.g. fertilisers), as well as a better understanding of the social capacities within the village