IOSR-JAGG   Volume-2 ~ Issue-4 ~ JULY-AUG-2014

Abstract: A design of electrode disk device of Electrical Resistivity (ER) has been tested its stability of the data and its relationship closeness with the electrodes stick devices. The designed electrode device was easy to use and recorded data quickly and accurately. The design of this device consisted of a sleeve electrode, a disk-shaped electrode, and shockbreaker; it was also equipped with wheels and a tool box. A testing process of the disk electrode device was done by measurements of apperant Electrical Conductivity (ECa) repeatedly to see the consistency of data measurement, with a correlation value of 0.988. The testing was also done by correlating the ECa data between the use of the disk electrode and the use of the stick electrode, with a correlation of 0.985 . The results of the testing showed that the disk electrode could be applied quickly and accurately to the ECa measurement of agricultural land with uneven topography and levees lied on rice fields.

Key words: Electrical Resistivity, apparent Electrical Conductivity, disk electrode device.

Abstract: An assessment of the geotechnical parameter in the formation of gullies in high risk erosion areas such as Mbaukwu town of south-eastern Nigeria is presented. The soil around the Mbaukwu gully erosion sites were investigated by collecting samples from the gully channels and excavation trial pits. The trial pits depth ranges between 0-1.0m and 0-1.5m, also samples were collected at depths of 35, 60, and 62m along the gully channels. Eight disturbed and undisturbed samples were collected and analyzed. Sieve analysis, Atterberg limits and Compaction tests were carried out on the selected soil samples. The soils are generally not uniform even though similarities exist between some. The liquid limit ranges from 32.00 to 46.00 and has a mean of 35.95. The Plastic Limit ranges from 17.50 to 28.10 and has a mean of 21.15. The Plasticity Index ranges from 10.50 to 20.00 and has a mean of 14.80. The Maximum Dry Density (MDD) ranges from 2.001 to 3.910 and has a mean of 2.490. The Optimum Moisture Content (OMC) ranges from 7.90 to 11.00 and has a mean of 8.980.Result of geotechnical investigation and laboratory analysis showed that the soil in the study area is majorly loose sand. They contain very small amount of clay which serves as a binding material. The lithology of the area is dominated by sandstone with very little binding material and is one of the chief reasons for the high intensity of the gullies in the area. The maximum dry density values are generally low which indicates that the soils are unconsolidated and friable. Enlightenment and awareness of erosion control should include land use habits of the people in their agricultural practices and care of vegetation. Concrete terracing of gully affected areas is recommended to reduce the impact or the force of rain-drop. This will restrict the widening of incipient gullies. Holistic rehabilitation development programs of monitoring the earth surface to reclaim devastated land as well as to ensure a safe environment should be encouraged.
Keywords: geotechnical properties gully erosion, maximum dry density, optimum moisture content, Mbaukwu..

Abstract: In India silica sands are produced from loosely consolidated sands and weakly cemented sandstones ranging from Recent to Pre-Cambrian in age. In this paper an attempt has been made to estimate the silica sand resources, belonging to Holocene age, located at about 20km east of Gudur town, Nellore District, Andhra Pradesh. Silica sand occurs in this region as dunes of marine origin covering an area of 110 Sq.Km. Ayyavaraiah et al (2013) reported that production and reserves estimated and declared by State Mines & Geology and Indian Bureau of Mines do not match and a difference exists. Hence an attempt has been made to estimate the actual reserves of silica sand deposits of this area using Google Earth imagery, GIS and field auger hole data. The total area that was mined already is about 9.538 Sq.Km. amounting to 117 Million Tons of silica sand that was produced in past 10-15 years with 59 Million Tons still to be excavated in the currently active mines. By surface area mapping using GIS, the prospective areas for further exploration and exploitation are suggested, giving rise to total prospective reserves of silica sand of 849 Million Tons.
Keywords: Glass-grade silica sand, Resource evaluation, GIS, Gudur, Nellore Dt., Andhra Pradesh