The Ultimate Checklist For Drilling Borehole In Zimbabwe.
Having and drilling a borehole is an asset that should last you at least 10 to 15 years at a very little ongoing cost, provided you do everything correctly at the start!
If you don’t, it can become a very expensive and time-consuming liability with continual repair or replacement of pumps. The causes of which could either be traced back to poor borehole construction or incorrect pumping or pump installation.
Nakiso Borehole Drilling has prepared a checklist to assist you when it comes to drilling a borehole in Zimbabwe. This includes your buying decision. One that should be based on ‘value’ and not on ‘price’ alone.
Nakiso Borehole Drilling has prepared a checklist to assist you when it comes to drilling a borehole in Zimbabwe. This includes your buying decision. One that should be based on ‘value’ and not on ‘price’ alone.
Location of Water:
1. You should do some ‘homework’ to determine if there are boreholes in your neighbourhood. Do this by checking with your neighbours to see who has a borehole, if they have water, how much and how deep is it. Then you can work out (very basic information used only to back up professional opinion) what your chances of finding water are.
2. Pinpoint the location for drilling the borehole. Get a siter or a geohydrologist to do this. Check on the past success rate of the person they usually use to ‘site’ their boreholes. In an urban environment, cultural interferences (powerlines, pipelines, cables etc..) preclude the scientific siting of the borehole. In a limited space urban environment the borehole is often drilled where the rig can fit in (average borehole rigs are + 15T and truck-mounted.
3. Check if the person you hired to site the borehole uses more than one method of cross-checking.
Choice of Borehole Driller:
1. Check references of previous clients who have had time to assess the quality of work over a reasonable period of time.2. Check what condition their equipment is in.
3. Make sure their drill rods are straight.
4. Check on the type of casing and the borehole screens to be used.
5. Check on the diameter of the borehole to be drilled. A diameter of 152 mm (6 inches / 216 mm (8 inches), is recommended for a domestic borehole.
6. Check if equipment can reach target depth.
7. Check if the company does borehole development and how the company will improve water yield if necessary – if he/she does not understand the meaning of borehole development, get another driller.
8. Check that you only have to pay the company if they drill to the depth specified (unless the company finds water at a lesser depth).
9. Check that the company will be able to continue drilling when hitting intersecting clay, unconsolidated sand or hard rock.
10. Check that the company will provide samples of the material of each and every metre drilled.
11. Check before drilling whether there are any add-ons to be considered – such as charges for double casing or depths exceeding 100m.
12. Check if the company provides records of work carried out, e.g. siter's report, driller’s report etc. When selling property, remember a borehole represents a substantial capital investment.
13. Check that the driller provides a record of exact depth at which the most promising water fissure is located. This information is vital to the pump installer to enable the company to select the correct pump for your needs.
14. Check if the company has a standard form of contract or terms. Of vital importance to both parties.
Other factors that need to be taken heed of by you, the end-user:
- The drilling company can never guarantee that they will intersect water and therefore it is the client who is at risk for the cost of the borehole. This is regardless of whether it is wet or dry!
- A modern drilling rig is large and heavy – in urban areas it can cause a certain amount of unavoidable damage, and the contractor cannot reasonably be held responsible.
- Drilling rigs are noisy and they generally make a great deal of mess, both these factors are unavoidable. In urban areas, neighbours should be warned that drilling will be taking place on your property.
- The local municipality or council may require that permission be obtained to sink a borehole. Discuss this with the drilling company or contractor, and find out who is responsible for making the enquiry.
- Ensure that there are no electrical cables, sewage or water pipes hidden under the ground where the drilling will take place.
- There are many unknowns, such as final depth, the amount required and time taken for development, so you need to agree on a suitable amount to be allowed for ‘add-ons’ with your contractor.
- Drillers levy a surcharge for drilling through very hard rocks, e.g. dolomite formation requires specialized expertise to drill into.
- Make sure that the driller caps the hole after drilling to prevent any foreign material entering the well.
