Tenders Are Invited For Community Borehole Drilling

Tenders are invited for Community Borehole Drilling in Rubkona County, Unity State 1 Mobilisation and demobilisation of all materials, personnel and equipment to site 1 2 Geophysical survey at the site in Rubkona and drilling supervision 5 Survey 3 Drilling of a borehole at the site in Rubkona area to a minimum diameter of 7 and to acceptable yield approved by the project supervisor Average total depth of well is expected to be 80+ m. including concrete well head and grouting 1m below ground level. 450 Meter 4 Top of casing to have metal cap with offset 2 hole with screw cap to allow for measuring of SWL. (Fuel, lubricants etc) 5 Installation of PVC plain casings with a (5) internal diameter for total depth of well except where screen casings are installed There should be at least 3m of 5 internal diameter PVC plain casing at the bottom of each well. 125 Pc 6 Installation of screen casings with an internal diameter of (5) . 25 Pc 7 Installation of gravel pack in annular space between casing and borehole wall using an appropriate method that prevents bridging. The gravel pack material should be clean material from riverbeds consisting of particles with a diameter of 2-4mm. The depth of the gravel pack should allow for 20% settlement above screen casings and have a cover to separate it from the sanitary seal. For average boreholes with diameter of 5 and 6 PVC casings with thickness of 6.5mm to a depth of 80m the average amount of gravel pack is to be estimated in cubic metres and the unit will be bags. 200 Bag (50kg) 8 Developing of borehole by airlifting for 4 hours until a stabilized satisfactory yield is reached, and the turbidity is less than 5 NTU. 20 Hrs 9 Performing a minimum of 12-hour step draw down and 12-hour constant rate pump test and 2 hr recovery to determine maximum yield. Yield, draw-down and recovery data are to be reported on standard borehole log. The pump used should have a discharge of at least 3,000 lt/hr. 120 Hrs 10 Clean and disinfect the borehole with hypochlorite calcium Solution 50mg/litre according to the calculated volume. 5 BH 11 Completion of Borehole Log report submitted within one week of completion of borehole, including GPS coordinates, casing details, filter pack details, constant rate testing procedures and results, recovery testing results, yield, draw-down, diagram of borehole lithology, depth, diameter, SWL, DWL, pump installation depth and motorized pump type, number of rising main pipes 5 Log 12 Physical field water quality test and Bacteriological test (samples to be tested within 72 hours of being taken from the borehole). 5 Test result 13 Chemical and heavy metals water quality test including for arsenic (samples to be tested within 72 hours of being taken from the borehole) 5 Test result 14 Installation of handpump and construction of apron (ordinary apron specifications)-2 set Tender Link : https://comms.southsudanngoforum.org/c/tenders