Elemental Minerals’ ongoing high grade Sintoukola potash project in the Kouilou Province in the south west corner of the Republic of Congo proved difficult with regards to exploration drilling due to the nature of deposits and the technical difficulties of core drilling in soluble potash salts. In addition to the technical difficulties of drilling the loose sand, clay and dolomitic limestone forming overburden.
Meridian’s experience with potash was one of the main factors that led to Elemental calling for their assistance in May 2011, and successfully operated three rigs on the project. These included two top drive rotary rigs – one Superock S5000 rotary and, and one Gemsa MP1200H multi-purpose rig, for a large diameter mud drilling in the top hole section and running/cementing casing as well as a diamond core rig (Coretech YDXL) for coring the evaporate sequence.
Andrew Pedley of Elemental Minerals said “No two projects are the same from a driller’s perspective. Meridian was keen to learn and adapt to the challenges of drilling at Kola. It’s not easy drilling, a very poorly consolidated sequence to 200 m then salt to the end of hole at 350 – 450 m, which of course needs a special set of skills to maintain excellent recovery.”
The Sintoukola Project comprises an exclusive exploration permit, for potash and associated salts, which covers an area of 1,436.5 km2 along the northern part of the coastline in the west of the country. Meridian Drilling also invested heavily in large mud pumps to allow top holes to be drilled through overlying sands and laterites and have been drilling using annular blow out preventers to guard against the possibility of shallow gas being encountered, using full tri-salt mud system to prevent dissolution of potash salts.