19/03/2025
BOREHOLE DRILLING WHAT TO LOOKOUT FOR
STEP 1 : (Siting & Driller) Ensure you as the customer you have engaged a reputable Borehole Drilling Contractor. Siting of your borehole, check your area out and obtain history from existing boreholes within the vicinity of where you would like to sink your borehole. Depths of existing holes with an example trees, anthills rocky out crops to mention a few.
Step 2 : Ensure the Drill is setup @ 90 degrees, a level can be used for this process, this is to ensure that all water aquifers are intersected.
Step 3 : Sampling of ground, ensure a sample for every drilled meter is taken and placed in rows 10m intervals as per correct industry practice, this helps identify soil structure as well both dry and water yielding aquifers. This will help you follow the depth of your borehole at any given time. This is a critical process which provides accurate information of your borehole.
Step 4 : Pe*******on Rate : This is critical if your driller drills to fast ‘’quick’’ small aquifers can be sealed up with HOT AIR and MUD. Cementing your water aquifers closed the average pe*******on rate varies from 3 to 5 minutes per drilled meter. (Time your driller)
Step 5 : Aquifer Identification, it’s important for your driller to identify your borehole aquifers and what they are yielding in-terms of water.. Make sure your water is measured to give you the flow rate which is approximately 60% with an airlift. Aquifer idenification is also very critical when placing screened casings to allow water to flow into your completed borehole. See examples …..
Step 6 : borehole yield, is your borehole drilled yielding good, satisfactory, poor water how do you determine this ? Very easy must be a constant flow of water when your borehole is being drilled, Surface water is inadequate and will not last in the dry seasons and eventually your borehole will dry up, ensure all and main aquifers are drilled and your drilling contractor provides a 6m sump not a 60m sump a sump being 6m below the last aquifer drilled.
Step 7 : Borehole construction, this is the most critical part of your borehole referring back to point 6 screens are to be placed at the aquifer intervals this allows water to flow into your cased hole 30% of the surface area of your casing should be screened make sure this is done.
# is your casing of a good quality
# is your casing not cracked or chipped
# is your casing the right size you have been quoted
# gravel filter must be only Granite, Dolomites or Quartz chips silica Granuals can be used if required do NOT let your driller trim in Limestone chips for your filter ( when limestone is exposed to oxygen after being submerged in water it exfoliates ‘’ decays’’ and will eventually close your screens.
Step 8: Borehole development, after construction has your borehole been developed what is developed ? It’s the use of air with a jetting tool to clean your water and remove the pulverized sediment from drilling out of your water, industry standard is a teaspoon of sediment in a 20lt bucket of water over a period of 2 hrs ( Do Not Settle for less)
Step 9 : Sanitry Seal, your contractor needs to cast a sanitry seal after completion this is a 1 cubic meter concrete block around your borehole casing, this seal stops your borehole from being contaminated with run off water and must have a bentonite plug.
Step 10 : insure the pump recommended will pump 60 % of the value of water in your borehole this will give you a borehole with a long life span do not over pump your borehole rather pump less and have a life yielding borehole.
Follow these basic fundamental steps by the book and methodically, you won’t go wrong we are here to help and advise our Zambian Brothers and Sisters DO NOT BE CHEATED OUT OF YOUR HARD EARNED MONEY !!!
We are PROUDLY ZAMBIAN 🇿🇲🇿🇲🇿🇲🙏
