Geostokos Limited -
Specialists in Ore Reserve Estimation


Experience by commodity


Consultancy and client information (1990->):
Mine planning and valuation

Statistics and geostatistics

Software advice
and development

Environmental issues

For current consultancy
click here


Isobel Clark pre-Geostokos

Geostokos pre-1990

Mine Planning and Valuation 1990 to present:

Mine planning assistance at Freda-Rebecca Mine, Zimbabwe for Cluff Minerals
(and later Ashanti GoldFields Zimbabwe).
Audit of project evaluation, Platinum Australia Ltd, Australia
Audit of evaluation procedures, Musselwhite Mine, Canada
Advice on sampling density, Platreef Resources (Pty) Ltd, RSA
Evaluation of mineral resources, Buhemba/Mwizi/Kilamongo deposit, Tanzania.
Audit of resources, tantalite deposit, Mozambique
Resource evaluation studies for Lonrho Platinum, South Africa.
Study of sampling methods and calibrations for Namco Diamond Mining, Cape Town.
Mineral resource and reserve valuation for Skorpion Zinc project in Namibia.
Assessment of Alexander Bay Diamond Mine, RSA
Evaluation of mining resources, Hartebeestfontein Mine, RSA
Tenke Fungurume project, Congo audit of computerised database
Resource Exploration, evaluation of projects in Zaire
Vaal Reefs Exploration & Mining Co. Ltd., audit of annual reserve statement
Blyvooruitzicht Gold Mining Co. Ltd., audit of annual reserve statement
Ghanaian Australian Goldfields, geostatistical modelling and advice on valuation
America Mineral Fields Int. Ltd., supervision of feasibility study --- valuation and geology
(2003, competent personís report Canadian NI43-101)
Lonrho Zimbabwe, advice on evaluation of small gold deposits
ISCOR Mining, audit of valuation for deposit in Zaire
Assessment of stockpiles at Norilsk, Osmium, London.
Evaluation of resources for Wadi Medden Project, Yemen.
Investigation of problems with Mine Call Factor for Libanon Mine, RSA.
Advice on valuation and sampling procedures for Nelson Gold, Tajikistan.
Stillwater Platinum Mine, Montana USA, grade control problems.
Tilden Magnetite, Michigan USA, geostatistical modelling of geological zones and various economic variables.
Pancontinental Mining, Western Australia, modelling and evaluation of shear-hosted gold deposits.
MIMCO, RSA, evaluation of gold mine.
Oryx Mine, Gengold, peer review of estimation methods.
Potgietersrus Platinum, JCI, benchmark evaluation.
Fergusson Stewart, Johannesburg, evaluation of Joel Mine.
Hartley Platinum, BHP Zimbabwe, peer review.
Ad hoc advice on mineral sands applications, for Shell Minerals, RSA.
Advice on sampling at Richards Bay Minerals, RSA.
Valuation of Mineral Sands project, California, USA.
Valuation advice for the Ayanfuri Project, Ghana for Cluff Minerals.
Public statement of remaining reserves at the Droogebult Mine, RSA.
Stillwater Platinum Mine, Montana; Lisheen Zinc/Lead project, Eire; Collahuasi Copper Mine, Chile;
all for Pittsburgh and Midway Coal Mining Company (a division of Chevron USA).
Palabora Mine, underground development, RTZ Management Services, Johannesburg.