“Arkhangelskgeoldobycha” JSC (Arkhangelsk, Russia):

Meshcheryakov M. G., Chief Executive Officer, e-mail: MMescheryakov@agd.lukoil.com
Golovin N. N., Head of Department, Chief Geologist, Candidate of Geologo-Mineralogical Sciences, e-mail: NGolovin@agd.lukoil.com
Verichev E. M., Deputy Head of Geological Department, Candidate of Geologo-Mineralogical Sciences, e-mail: EVerichev@agd.lukoil.com

Grib Kimberlite Pipe was discovered in 1996. The pipe appraisal was accomplished in 1996–2001. To this effect 69 appraisal wells (total length of 20.2 thou m) and 27 water wells (total length of 4.4 thou m) were drilled. Representativity of core sampling was estimated with the help of bulk sampling in 7 wells 560 mm in diameter. Diamond reserves were demonstrated down to 610 m. In 2000–2004 exploration was performed by means of drill wells. The check core-sampling wells 224 mm in diameter were drilled. In total there were 39 exploratory wells (total length of 21.8 thou m) and 5 water wells (total length of 2.4 m). The category C1 and C2 diamond reserves were demonstrated down to 1010 m. in 2008–2010 the deposit was additionally evaluated in order to refine cost estimate of diamonds as well as to specify mining-and-geological and hydrogeological conditions for the technical and economic substantiation of quality requirements. With this end in view, 10 wells 610 mm in diameter and 600 m long and 23 water wells and soil bores 70 to 600 m in length were drilled. Based on the exploration data, the constant exploratory quality requirements and diamond reserves were confirmed for the combined open-pit and underground mining technology: down to 460 m depth—open-pit mining that is then transferred in the underground mining to the depth of 810 m below surface. Since March 2011 stripping of the deposit has been carried out.