COO Mike Parker explains our difference of approach over previous explorers, and the importance of overlapping co-incident target evidence.
Top tier exploration approach in a junior company
Chesterfield Resources has a number of exploration advantages over historical exploration that has been conducted in Cyprus. While many orebodies have been mined throughout the history of the island, we believe there are many more yet to be discovered.
Chesterfield has five advantages over historic explorers:
The ability to drill efficiently near old mines looking for mine extensions
From Phoenican times until the mining industry halted in the mid 1970s, copper explorers in Cyprus had to rely on surface outcrops of copper mineralisation to locate ore bodies. They would then start to mine around the outcrop and follow the ore bodies down until they were exhausted. Even in the 1970s, exploration drilling was still expensive and slow.
There was, therefore, little exploration in the vicinity of large historic mines, which provides an opportunity for a modern exploration company such as Chesterfield. VMS deposits such as those in Cyprus tend to form in clusters. Where you find one mine, there are normally others nearby.
Using advanced techniques to track and locate deep mineralised deposits under basalt flows
Secondly, large areas of the mineralised belt are covered by ancient sheets of basalt. There is, therefore, an extremely high likelihood that many ore bodies are buried under this basalt “cover”. Because there is no surface outcrop, previous explorers would not have been able to locate these orebodies. Chesterfield can use satellite analysis to analyse where faulting systems can be seen moving undercover. We then use geophysics to “look” under the layers of cover rock for anomalies that indicate mineralisation. Geophysics techniques include magnetic surveys, IP (induced polarisation) and airborne surveys such as helicopter VTEM and Mag drones.
A greatly improved understanding of where and faults and traps may host deposits
Thirdly, the understanding of Cyprus geology has advanced considerably in the last 45 years. We now have a much better idea of how hot metal-bearing fluids would have flowed into faulted systems, so-called “permissive pathways” and then become trapped. Advanced structural geological thinking has replaced many of the traditional theories about the formation of Cyprus style deposits.
A substantial exploration tool box to provide co-incident target evidence
We have a substantial exploration tool box at our disposal. Once a target has been identified, it is mapped, various types surveys are run and historical archive evidence gathered. All this data is combined on a computer system called GIS. It is the over-lapping co-incidence of this evidence that gives strength to the final targeting decision and the specific location of the test holes to be drilled.
Chesterfield also puts considerable emphasis on geochemistry, especially soil sampling. This involves digging a large number of sallow holes and sending soil samples to a lab to analyse for traces of metals that may have found their way to the surface over many years from the rocks below. While this may appear rudimentary, it is still an effective technique to gather evidence of what is happening below the surface.
Chesterfield has also put a substantial amount of work into finding and analysing information in Cypriot Government mines services archives. This can include mining information from when the industry was active, and numerous surveys and academic reports which had been completed on the island since. The industry closed 45 years ago which means there are still a number of geologists alive from that period. We have built good relationships with these geologists which has helped greatly with our knowledge of prior exploration and production.
Disciplined approach to target ranking, prioritisation and development
Chesterfield has a very disciplined approach to reducing the search area on its land packages to identifying a series of targets. These targets are then ranked, prioritised and resources allocated to them accordingly. The ranking of the targets will change as evidence is gathered and analysed. The company puts a great deal of effort into developing these targets, running various surveys and analysing data before selecting the best targets to test with diamond drilling.
The pyramid graphic below illustrates the exploration process from identifying land packages to diamond drilling. It is a multi-stage target development process, and far more exacting than many junior explorers, and a huge advance on the historical approach to exploration.
The pyramid graphic below illustrates the exacting and disciplined process that Chesterfield uses to develop its targets before taking the expensive decision to test them with diamond drilling.
In its next phase of exploration, Chesterfield intends to use the emerging technique of drone magnetic surveys to quickly cover large areas of ground.