For the first time in India, Indian Strategic Petroleum Reserve Ltd. (ISPRL) undertook three large crude-oil storage projects, each having a capacity of 1.25 million tonnes of crude oil, out of which two awarded to Anand Mincons for planning and designing the entire ventilation system of network of long and large caverns consisting of two 120m deep shafts, with one Main Access Tunnel (1000m(L) x 32m(H) x 20m(W)). The ventilation was carried out separately for the shafts and for the two horizons with an intervening parting of 40m. In the upper horizon for constructing water-curtain Galleries for the purpose of maintaining the strata fully kept under pressure with water so as to provide a water seal between the crude oil storage tunnels and the upper horizon of water curtain galleries. The Lengths and Cross section area of tunnel also varied. Typical layouts of the two horizons are enclosed.
Because the availability of a single Main Access Tunnel for ventilation of both the horizons was proposed with the following approach:-
1) To utilize the limited size and numerous bends EnRoute.
2) To reduce the investment on capital and recurring power cost by:-
a) Maximizing the size of ducts so that the ventilation pressure required is reduced and maximum air flow is delivered.
b) Smoothening the various bends with larger radii.
c) The judicious use of dampers use to regulate the air during different operations like mucking, drilling/charging/ support work etc.
d) The use of flexible ducts with double suspension so that bigger clearance is obtained below the duct-lines in the event of stoppage of the main ventilation fans.
Because of the paucity of space and the need to ventilate the compulsive need to ventilate multiple faces from a single outlet, use of Regulators have been suggested at judicious locations to regulate air-flow as and when the need arises to vary the flow at the respective face-ends depending upon the varying air-requirements to suite more air-flow during mucking operation & relatively during drilling/ charging........
The Main criteria was to minimize capital expenditure on fans and recurrent power cost. The proposed standard provided SPRL an excellent standard of ventilation of fact fully appreciated by both workers as well as SPRL as evident from their remark. "The Best Site of the Year ; A Must See site."