Abstract:
Hindalco Industries Ltd Muri works Alumina plant requires water of about 500 m3/hr after expansion at Muri, Ranchi District, Jharkhand. No deep-seated fractures could be seen in the area. Detailed groundwater exploration has been carried out through a number of Vertical Electrical Sounding (VES) in the Subarnarekha River upstream of Uraongarahanala confluence to select a suitable site for water sourcing. Hindalco has drilled six test bore wells in the riverbed to confirm thickness of the alluvial stratum determined through the geophysical investigations. The geo-technical investigations indicated that the alluvium has a maximum thickness of 4.6 m with an average thickness of 3.5 m. The alluvium comprises medium to coarse sand with gravels, clayey sand/sandy clay with mica flakes in the riverbed. Standing water level in the six bore wells during March 2005 was close to the ground level and during monsoon period the entire reach experiences fl ows with 1 m water column. The permeability of the riverbed alluvium varied from 60-80 m/day. Based on the above geo-technical results and geophysical data sets an intake system from the river bed (infiltration gallery) with a Jack well and a caisson on the right bank has been recommended in the Subarnarekha river at Biseria village.
The infiltration gallery may be expected to yield about 12,000 m3/day under the prevalent river flow regime condition. During high river stage more water could be drawn from the intake system. Construction of infiltration gallery with 1 m diameter perforated intake pipes of 131 m length connected to a Jack well is underway at the site in Biseria village by Hindalco-Muri works, Muri, Ranchi district in Jharkhand and it is expected to yield about 12,000 m3/day form the Subarnarekha river bed aquifer. Water budget for meeting the above requirement has been estimated from a groundwater flow model study.
