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This paper presents an easy-to-understand and easy-to-use methodology for monitoring the neutralization potential of residues derived from coal preparation. The methodology was developed based on the chemical composition of the waste and the relationship between calcium and sulfur. The effectiveness of this, in the control of residues, is demonstrated through in situ testing in a coal preparation plant in San Juan de Sabinas, Coahuila. The tests were carried out by collecting samples in three waste streams for five days at the plant. The methodology presents a strong linear correlation between the neutralization potential and the Ca/S ratio of 0.91. The estimation of neutralization potential through the Ca/S ratio represents a practical, easy-to-apply methodology that saves time and favors the decision-making required by waste management plans, to avoid the generation of acid drainage in coal waste. [ABSTRACT FROM AUTHOR]

A hydrochemical characterization of the Northern Great Wetland of Ciego de Ávila province, Cuba, was carried out in order to identify the factors changing water physical and chemical properties and the current status of conservation or deterioration of the aquatic environment. Temporal and spatial behavior of temperature, salinity, oxygen saturation percentage and pH was evaluated based on analytical results from eleven water samples and temporal and spatial distribution maps generated using Surfer 8.0. It was found that interchange of ocean water, depth of aquatic bed and, to a lesser extent, surface water drainage in inland bays Los Perros and Jiguey are the factors which most influence temporal and spatial behavior of the properties analyzed; therefore, it is recommended to interconnect inland lakes with ocean water to contribute to the decrease of salinity and increase of pH and have more stable temperatures throughout the year. [ABSTRACT FROM AUTHOR]

This study presents a semi-quantitative mineralogical evaluation of the non-nickeliferous weathering crusts in the areas of Baconal, El Culebro, Caimanes and Farallones in the northeast of Cuba. The main objective of this study is to determine the main mineral phases, their vertical distribution and concentration, as well as the degree of mineral transformation in the weathering profiles. Sixteen samples were analyzed by X-Ray Diffraction and the diffractograms were used in qualitative and semi-quantitative phase analyses using ANALYZE and AUTOQUAN programs. The degree of mineral transformation in relation to phase distribution and concentration as weathering progressed was evaluated using the Mineralogical Index of Alteration. The main mineral phases present in Baconal and El Culebro are Kaolinite (50-75%), Kaolinite-Montmorillonite (50-75%), Quartz (25-50%), Plagioclase, mainly Albite (25-50%) and Hematite (<10%). In Caimanes and Farallones the principal mineral phases present are Kaolinite, Hematite, Quartz, Potassic feldspars, mainly as Orthoclase, all with more than 75%, Halloysite (<10%), and Montmorillonite (<10%). Extreme primary mineral transformation is evidenced in the intermediate and upper layers in Baconal, El Culebro and Caimanes (Mineralogical Index of alteration values between 29 and 98 %). This transformation is also evidenced in the whole Farallones profile (98-99 %). In conclusion, the non-nickeliferous weathering crusts in Baconal, El Culebro, Caimanes and Farallones are mainly kaolinitic clays. [ABSTRACT FROM AUTHOR]

In this work, a study of the fractional distribution of mass and content of the metal value presented in the black sands of the placer Mejías is done. The particle size and magnetic field intensity was using as separation properties. The models that describe the distribution behaviour of the principal elements presented in this placer were obtained with the function, , and , β(l), β(I) y β(l,I). [ABSTRACT FROM AUTHOR]

Hydrogeological resources in the semiarid regions of Mexico support the economy and essential domestic activities of around 17 million people. However, adverse climatic conditions and overexploitation of aquifers affect the quantity and quality of the resource, added to problems of anthropogenic pollution and the salinity of water bodies. The Region Carbonífera aquifer represents the primary hydrogeological system in the most important coal-mining region in Mexico, located in the state of Coahuila. In this work, we present a complete dataset of 157 samples from surface and groundwaters sites have been used to characterizethe physicochemical and isotopic processes responsible for the composition of circulating waters, clarifying their origin, and to evaluate the water quality in terms of human consumption and irrigation use. The aquifer is mostly represented by Ca2+-Mg2+-SO 4 2- and Ca2+-Mg2+-Cl- type waters, that supports salinization problems in 76% of the samples as well as sulfate excess. The origin of this chemical behavior seems to be the result of three main processes: 1) dissolution of soluble salts (gypsum, anhydrite and halite), 2) high surface evaporation under semiarid climate conditions, and 3) ionic and reverse ionic exchange. Processes 1 and 2 are also supported by the enrichment trends in the δ18O and δD signatures. For human consumption, 21% of the samples show high concentrations above the maximum permissible limits of the Official Mexican Standard (NOM-127-SSA1-1994) in total dissolved solids, Cl−, Na+, and SO 4 2−. Additionally, 80% of the waters have some irrigation limitations due to excess sodicity or salinity. The worst quality waters for human or irrigation uses are located south of the aquifer in the municipalities of Juárez and Progreso. This study exhibits the complex hydric situation of the aquifer, raising awareness of the need to seek alternative sources, rational exploitation of resources, the use of crops that better adapt to these semiarid conditions, and intensifying hydrochemical monitoring in the region. • Aquifer in semi-arid regions of Mexico affected by salinization. • Evaporation processes and the dissolution of evaporites are the cause of excess salts and poor water quality. • Ca2+-Mg2+-SO 4 2- and mixing waters are dominant. [ABSTRACT FROM AUTHOR]

Mineral deposit descriptive models are valuable geological information network usefull to explore and assessment the territories with these atributes in their geologic pattern and makes them perspectives for the discovery of new mineral resources. In this paper a generalized approach is given about weathering as main process in the formation of laterites as well as three proposal of Fe-Ni-Co laterite descriptive models developed on Mayarí-Baracoa Ophiolitic Belt located in Eastern Cuba. [ABSTRACT FROM AUTHOR]