Solution mining of multi-component magnesium-bearing salts — a realization in the Netherlands

CIM Bulletin, Vol. 79, No. 891, 1986

D. BUYZE Noordelijke Zoutwinning B.V. and H. LORENZEN Billiton International Metals B.V.

Magnesium-bearing salts occur in the Zechstein Basin in the northeastern part of the Netherlands at a depth of 1500 m to 2500 m. Exploration results justified the exploitation of these salts by means of solution mining for the production of refractory grade magnesium-oxide. This paper discusses design criteria, operation parameters, and methods used for magnesium chloride solution mining by Noordelijke Zoutwinning B. V, (NOZO), an operating company of Billiton International Metals B. V. A unique variation of widely used solution mining techniques has been developed for mining the complex Veendam salt deposit. NOZO extracts salt through deviated wells with a set of parallel, suspended tubings. Cavern fluid pressure is maintained close to that of overburden rock. These special design features provide an answer for the complex characteristics of the minerals, halite, carnallite, bischofite and kieserite, from which a solution rich in magnesium is generated. Dissolution chemistry and rock mechanical behaviour of these salts are unlike those of rock salt. Throughout a few years, NOZO demonstrated adequate process control while they continue improving the operation.

Keywords: Industrial minerals, Salts, Solution mining, Magnesium, Drilling, Brine production, Mud system, Coring, Well patterns, Rock mechanics.