A study of geohydrological and rock engineering environment at Lappvattnet experimental mine

Abstract

The paper describes a hydrogeological and geotechnical study of rock mass at an experimental nickel mine at Lappvattnet, Sweden. The mine is situated 30 km south-west of the twonship of Skelleftea and was mainly developed for the exploration purposes. The mine consists of 1000 m of underground roadways from where a number of diamond cored boreholes were drilled for geotechnical studies and mine valuation. The main problem encountered during the development stage of the mine was very high quantities of ground water inflows at relatively high hydraulic pressures. The geological and hydrogeological conditions along the length of the drifts are described together with the methods used for ground-water inflow control. The study shows that there is a strong need for modifying the grouting methods to suit the rock conditions in order to control the ground-water inflows. A discussion regarding the need for a detailed geotechnical investigation prior to the planning and design stage of the project is also included.