Mineralogical and Geotechnical Properties of Clay Minerals in Northern Borno, Nigeria

Clay generally refers to either fine grained earth material with particle size of less than two micron (< 2 m) or group of hydrous aluminum silicate minerals that are characterized by sheet silicate structure of composite layers stacked along the C-axis. They are common deposits found in most geological setting like in fine grained sedimentary rocks such as shale, mudstone, and siltstone, in fine grained metamorphic slate and phyllite. The interest in clay deposits arises from its numerous uses of the mineral group and the behaviour of soils constituents when used as engineering soil and its resultant effects on engineering structures like roads, dams, bridges and houses. Evaluation of the soil properties of the Chad Formation indicated that the plasticity characteristics of the samples are of low to medium plasticity as indicated by matching the result with the DIN. chart. The results of free swell showed that the samples are susceptible to swelling when they absorbed water. The particle size distribution tests indicate that the percentage of fine (i.e. samples passing the 75µm sieve) is about 1.7 % implying that the grain sizes are within the texture of medium grain fraction