SPL REPAIR/REPLACEMENT TO BOREWELL AND ALLIED WKS AT AIR FORCE STATION HALWARA

Material & Labour for drilling trial bore by rotary / reverse rotary method in any type of strata consisting of 250mm dia drill bit for depth upto 200 mtr in sequence from ground level as given below for borewells complete as per IS -2800 (Part -1):1991(Reaffirmed 2001) including removal of surplus soil at a distance of 100 mtrs as directed. The following test and reporting will be carried out by the contractor and approved by GE complete all as specified & directed:- The Boring is to be carried out through agency registered with Central Ground water Authority :- (i) Recording the water bearing horizon. (ii) Taking the samples from the bore well cutting for every 3mtr interval and every change in strata if less than 3 mtr. (iii) Preparation of litho logs based on these samples. (iv) Drill time log to be prepared and prescribed Note: - The depth of trial boring of the tube well at the site indicated by the GE is anticipated to be 200 m below ground level. The depth may, however be ordered in writing to be varied by the GE up to a maximum of 25 % of the above mentioned depth (plus or minus). If the GE decided that suitable water bearing strata is not available in the aforesaid bore or the boring cannot be continued further on account of the type of strata met with, he may order the contractor to bore at other site(s) selected by the GE, until suitable water bearing strata is met with or boring cannot continue further on account of the type of strata met with provided the total number of bores (including the first bore) does not exceed two numbers the decision of the GE shall be final & binding .The bore well work shall be start only after successful result of trail bore and approved by GE.

Material & Labour for development of trial bore to be drill by using suitable size of bit to accomodate 300/200mm dia assembly pipes leaving 5" annular space around assembly pipes from 250mm to 675mm upto 150 mtr from ground level. The Boring is to be carried out through agency registered with Central Ground water Authority, complete all as specified & directed. Note :- (i) A cement Seal between 3 Mtr and 5 Mtrs below Ground level is to be provided to avoid Surface contamination to the ground Water. (ii) Local Clay should be filled between 5 and 25 mtrs and also between Ground level and 3 Mtr (iii) Gravel of appropriate size is to be shrouded in the annular space around the well assembly beyond 25 Mtrs.The cost of Gravel shall be measured and paid separately.

Material & Labour for development of trial bore to be drill by using suitable size of bit to accomodate 300/200 mm dia bore assembly pipes leaving 5" annular space around assembly pipes from 250mm to 525 mm from exceeding depth of 150 m below ground level. The Boring is to be carried out through agency registered with Central Ground water Authority, complete all as specified & directed. Note :- (i) Gravel of appropriate size is to be shrouded in the annular space around the well assembly beyond 150 Mtrs.The cost of Gravel shall be measured and paid separately.

Supplying and assembling including jointing, lowering & fixing in position plain mild steel sheet casing (ERW) pipe 300mm dia Heavy duty confirming to IS: 4270-2001, pipe jointed and welded with coupler, Welding shall be done through out the circumference of the pipe and coupler rings both sides, complete all as specified & directed.

Supplying and assembling including jointing, lowering & fixing in position plain mild steel sheet casing (ERW) pipe 200 mm dia Heavy duty confirming to IS: 4270-2001, pipe jointed and welded with coupler, Welding shall be done through out the circumference of the pipe and coupler rings both sides, complete all as specified & directed

Supplying and assembling including jointing, lowering & fixing in position stainless steel v wire screen with 1mm slot, pipe 300 mm dia confirming to IS: 8110-2000(Reaffirmed 2006), pipe jointed and welded with coupler, clamp as per manufacturers instructions, Welding shall be done through out the circumference of the pipe and coupler rings both sides, complete all as specified & directed.

Supplying and assembling including jointing, lowering & fixing in position stainless steel v wire screen with 1mm slot, pipe 200 mm dia confirming to IS: 8110-2000(Reaffirmed 2006), pipe jointed and welded with coupler, clamp as per manufacturers instructions, Welding shall be done through out the circumference of the pipe and coupler rings both sides, complete all as specified & directed.

S&F mild steel reducing socket 300mm x 200mm including welding MS strip 40mm X 6mm (6 Nos) on each joint extended 100mm on each side, complete all as specified & directed. Note :- The Wall thickness of the socket side shall not be less than 7.04mm.

Testing of water for potability by chemical analysis such as PH value , Disssolved solids, hardness as CaCO3 , Calcium , magnesium , chlorides , Sulphates, nitrate, Alkalinity , iron turbidity NTU, Mineral oil, Colour Hazen Units, taste Odour, residual free Chlorine, total caliform per 100 Ml( Microbiological test) & E Coli per 100 Ml (microbiological test) as well as bacterriological portability from any Govt approved Laborotary and the report shall be submitted to Engineer in Charge, complete all as specified & directed.

Supply & packing of pea gravel 2mm to 4.75 mm size as per IS 4097:1967 (Reaffirmed 2008) of natural shape brought directly from river bed and packing around the casing pipe/slotted pipe in the bore well to entire depth upto ground level, complete all as specified & directed.