Limestone Mining in Developing Countries; Hydro-Environmental and Ground Water Potability Impacts

Adewale A. Sobande, James C. Beetseh

Due to the unavailability of alternatives, most developing countries rely heavily on various forms of ground water abstraction for potable water supply. Rapidly expanding mining and petroleum-related activities are however exerting significant impacts on the ground water resources, the qualitative extents of which are yet to be thoroughly investigated, or fully understood. The present study attempts to conceptualize by case study, ground water vunerability consequent upon mining activities within limestone terrains. Ground water quality, spatial variation and relation to sub-surface flow patterns where examined in conjunction with structural geologic features within two typical limestone terrains in Nigeria. One of these has been earmarked for mining/petroleum development but is currently undeveloped, while the other is at an advanced stage of development. Extensive chemical and bacteriological pollution was detected in the ground water of the latter with agneous nitrates and chlorides reaching relatively ominous proportions. In determining the controlling hydro-dynamic processes, a number of pollution agents and catalysts, directly related to the industrial activity were identified. Dominant among these are the indescriminant use of chemicals, improper disposal of industrial wastes and the creation new geologic conduicts within the hietherto compacted rock for accelerated contaminant migration. The local and regional hydro - environmental impacts of this and related scenarios are examined, and culminative effects on groundwater potability discussed inter alia.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995