By Colin Rice
Colin Rice Exploration and Training (Pty) Ltd
Any drilling fluid risk management strategy must take account of all of the areas of risk - here are some practical points to assist.
This is the third article of Part 1 of our Technical Series on Drilling Fluids. Click here for an outline of the entire Technical Series on Drilling Fluids.
From reading article 1 and article 2 in this Technical Series, it should be clear that the major control measure that we can use to control the risks associated with drilling fluids is to ensure that all additives are non-toxic (or non-damaging). In considering toxicity we have to consider all of the elements of the operation that will be exposed to risk; human beings (the drill crew!), animals, plants and underground or surface water resources. I therefore propose that the following could be used as a basis upon which a mining company can build a risk mitigation plan:
- Ensure that all fluids, oils and greases are “non-toxic” – this is done by interrogating the MSDS for each product. Ensure that an accurate, valid and up to date MSDS is available on site for every chemical, oil and grease that will be used.
- Before any new chemical is brought to site ensure that the MSDS is interrogated to ensure that it is valid and up to date and that the product is non-toxic.
- Ensure that the drilling fluid formulation (dosage rates and types of chemicals used) is correctly followed by the contractor.
- Ensure that boreholes are designed so that aquifers from which potable water is being or can be produced are cased off and that a suitable sanitary seal is placed around the casing.
- Ensure that all personnel who will be involved in mixing and maintaining the fluid system are correctly trained and are competent to handle the chemicals.
- Ensure that all personnel who will be involved in mixing and maintaining the fluid system wear all PPE as required by the MSDS.
- Keep all chemicals, liquids and solids, in a secure place to prevent access by animals or unauthorised people.
- Clean up spills as soon as possible and dispose of any contaminant soil or materials as directed in the MSDS.
- Dispose of empty containers and packaging as specified by the MSDS
- Keep circulation losses to a minimum – remedy any losses as quickly as possible.
- Dispose of drilled cuttings as directed by the MSDS or as directed by the Project Environmental Plan.
- Dispose of used drilling fluids as directed in the Project Environmental Plan.
- Keep the usage of drilling fluid additives to a minimum without compromising the integrity of the borehole.
Many of these objectives can achieved by using a mechanical solids removal unit – in March 2018 we will focus on the application and benefits of using a mechanical solids removal unit to help manage risk.