The state of Estonia has given the Geological Survey of Estonia the task to carry out geochemical investigation of Estonian basement rocks. The objective is to compile a geochemical database of the basement rocks and assess their metallic ore-forming potential. To reach this goal, drilling operations are required together with accompanying geophysical exploration. Moreover, state-of-art geochemical research of the drilled cores will be crucial. Earlier geochemical studies took place before the World War II, and during the 1960s, and the level of accuracy of those geochemical analyses does not qualify for current international research standards. It is not technically feasible to perform repeated analyses of cores drilled in the past, as the existing cores cannot be divided into necessary intervals (in those times, a drill core as a whole was used for sampling).
The plan last year was to carry out boring at two exploration areas, in Jõhvi and Uljaste. However, as the drilling operations of Jõhvi took longer time to accomplish than expected, the procurement of Uljaste had to be denounced.
With the announced international procurement the Geological Survey looks for an operator for drilling one hole within the Uljaste exploration area, approximately 700 m in depth. Similarly with the drilling at the Jõhvi exploration area, also the Uljaste drill hole will be inclined. However, it will be essentially closer to the vertical, or at an angle of 80 degrees. The Uljaste exploration area has been selected on the basis of earlier exploration in the region of the Uljaste polymetallic geochemical anomaly and its surroundings. A former drill hole, No. F227 is located in the vicinity of the chosen exploration area. The largest geochemical zinc anomaly within the whole Uljaste region has been determined from the drill core of this hole.
The head of the Department of Geological Resources of the Geological Survey, Tiit Kaasik: “We continue exploration of national geological resources that was started last year. Particularly in the current circumstances it is essential that we should investigate our potential resources and possibilities for their valorisation. Boring of deep drill holes in Jõhvi last year was the first case in Estonia after a hiatus of 30 years in such endeavours ordered by the state. We learned considerably of that process. The objective of the currently planned Uljaste drilling operations is analogical – most of all to control the validity of information gained in earlier studies and achieve fresh material for arranging complementary analyses with modern methods. The bored drill core will be deposited at our Arbavere research centre, where the geologists of the survey will carry out geophysical and geochemical investigations of it.”
The deadline for sending tenders is 4 May 2020. Operations at the Uljaste exploration area have to be accomplished by 15 September 2020.
