The Case for Integrated Drilling Programmes in Mining
By Graham Trusler and Robel Gebrekristos | Presented by Graham Trusler at the International Mine Water Association (IMWA) Conference 2026, Jeongseon, South Korea
By the time a large mining operation in Africa moved from exploration into detailed project investigations, more than 5,000 boreholes had already been drilled across the site. Few projects could offer for a richer view of the subsurface: thousands of direct intersections with the orebody and the rock around it, each one paid for in rig time and site access.
As extensive as it was, the drilling was far from over. The project went on to drill 55 dedicated hydrogeological boreholes, eight geochemical boreholes, more than 100 geotechnical boreholes and numerous sterilisation holes, much of it in areas already covered by exploration drilling. The hydrogeological programme alone cost more than US$1 million, excluding the geotechnical and sterilisation work and the additional campaigns delayed the investigations that depended on them.
The problem was not a shortage of drilling. The more than 5,000 exploration holes had been logged primarily for a single purpose which was defining the orebody. While the information that hydrogeologists, geotechnical engineers and geochemists would later need was not routinely recorded.
That case study sits at the heart of a paper by Digby Wells specialists Graham Trusler and Robel Gebrekristos, presented at IMWA 2026 in July. The point it makes: mining projects can leave valuable data uncollected when drilling is planned for only one purpose.
Why do drilling programmes miss cross-disciplinary data?
Drilling is a primary source of information throughout the life of a mining project. Exploration, geotechnical design, hydrogeological characterisation, geochemical risk assessment, sterilisation and metallurgical testing all depend on what comes out of boreholes. Despite this common reliance, drilling programmes are typically planned in isolation, with each department focused on its own immediate objectives.
Exploration drilling is conducted at scale to define a resource but logging is often limited to lithology. Later in the project, new boreholes are commissioned for hydrogeological, geotechnical or geochemical investigations, frequently across the same ground. Each remobilisation adds to costs and extends schedules while it produces datasets that sit disconnected from one another, making it harder to see how geological, hydrogeological, geotechnical and geochemical conditions interact.
What additional data should exploration boreholes capture?
The most striking finding from the case study is how little was needed to capture the missing information at the start. With prior planning most of it could have been collected during the original exploration programme at marginal additional time and cost.
For the hydrogeologists, that means recording groundwater strikes, water levels, drill-fluid losses and fracture characteristics as each hole advances. For the geotechnical engineers, it means capturing core recovery, rock quality and joint characteristics. For the geochemists, it means noting sulphides, oxidation and the other indicators that support early prediction of acid mine drainage and retaining sample material for later test work.
Many of these observations can be collected from the same borehole without changing the rig, a different hole or, in most cases, a different logging team. The essential element is reaching agreement before drilling begins on what each discipline needs and who will record it.
“Every borehole is an investment. By planning together and collecting data that serves multiple disciplines, we can make better decisions while reducing unnecessary drilling, project costs, health and safety risks and environmental impacts.” – Robel Gebrekristos
What does an integrated drilling programme involve?
An integrated programme does not require every borehole to serve every discipline. It requires drilling to be treated as a project-wide resource rather than a departmental activity. In practice, that means:
- involving all relevant disciplines in drilling programme design;
- agreeing minimum observations, samples and tests to be captured in every hole;
- training logging teams to recognise and record information relevant to other disciplines; and
- establishing common data standards, with borehole data stored where every team can reach it.
Shared databases and digital tools support this by making borehole data easier to capture, interrogate and compare against future investigation needs. Technology follows agreement: teams must first decide what information matters, how it will be recorded and how it will be distributed.
What did IMWA 2026 reveal about mine water management?
South Korea was a pointed setting for a conference on mine water. The country has a mining history spanning roughly 60,000 mines, around 90% of which are now closed; some 60 water treatment plants still operate at closed sites, managed by a dedicated state entity, the Korea Mine Rehabilitation and Mineral Resources Corporation (KOMIR). It is a working demonstration of how long the water-related consequences of mining outlast the mining itself and of why decisions taken in a project’s first years still matter decades after closure.
For Graham, presenting to delegates from more than a dozen countries the dominant theme was the gap between knowledge and action.
“What struck me at IMWA is that Africa already has the technology and the skills to solve many of the water challenges at our current and legacy mines. What we need now is not another study it is a sharper focus on implementation.” Graham Trusler
Drill once, decide better
Better outcomes in mining rarely depend on doing more work. More often, they depend on planning the work already scheduled. A borehole is expensive, disruptive and difficult to repeat; treating it as a project-wide asset strengthens the evidence base for mine planning, infrastructure design, environmental assessment, closure and risk management alike.
Every borehole is an opportunity. The value lies in planning for it early.
Digby Wells Environmental’s hydrogeology, geochemistry and geotechnical specialists work with mining clients to design integrated drilling and investigation programmes across the project lifecycle. From exploration through feasibility to closure. To discuss how an integrated approach could reduce cost and risk on your project, contact our team at www.digbywells.com/contact-us/.
The link to the full article is below:
Saving money and improving data collection when drilling on mining projects
Dr Robel Gebrekristos is Technical Lead: Hydrogeology at Digby Wells Environmental in Johannesburg, South Africa. He has over two decades of experience in mine hydrogeology, groundwater modelling, dewatering, water resources and environmental assessments across Africa and internationally. His current interests include integrated mine water management, groundwater modelling, and improving the collection and use of hydrogeological data to support better mine and water supply planning and decision-making.
Graham Trusler is one of the founding partners of the company and is a Non-Executive Director of Digby Wells Environmental. He holds a MSc (Engineering) and a BCom. Degree. He is a registered professional engineer with the Engineering Council of South Africa. He is also registered as a Chartered Chemical Engineer with the Institution of Chemical Engineers, is a member of the Water Institute of South Africa and a lifetime member of the American Society of Mining and Reclamation. Graham has 30 years of experience within the mining industry in metallurgical production, research and environmental issues.fu