Effective selective mining relies heavily on high quality geological data and assay data. Such assay data is dependent on effective sampling protocols, sample preparation techniques, assaying practices and well founded quality assurance/quality control (QA/QC) procedures. This paper describes recent developments in grade control sampling at PT Nusa Halmahera Minerals high-grade Kencana gold mine at Gosowong Indonesia and presents a case study in identifying, minimising and monitoring random and systematic sampling error including the use of duplicate sampling and the Thompson Howarth technique for quantifying random sampling error._x000D_
FORMAL CITATION:Carswell, J T, Yulia, K, Lesmana, D and Steamy, K, 2009. Grade control sampling quality assurance/quality control in a high-grade gold mine - Gosowong, Indonesia, in Proceedings Seventh International Mining Geology Conference 2009, pp 283-290 (The Australasian Institute of Mining and Metallurgy: Melbourne).