Abstract: The invention relates to cartridges containing a mortar composition capable of being hardened by reaction with an aqueous liquid such as water. The cartridge is initially sealed and is perforated along its longitudinal axis just before use, after which the mortar composition is caused to come into contact with an aqueous liquid to cause hardening thereof. According to one method of application, the cartridge is immersed in water which causes a wetting of the mortar composition centrifugally, i.e. from the axis towards the outside. The advantages of such a cartridge are that rigidity can be maintained during activation of the mortar with ease of use and, if required, visual evidence of complete wetting of the mortar.

Abstract: A process for the protection of the surface of the terrain in mine galleries from deterioration due to the surrounding atmosphere is characterized by the operation of spraying onto the wall to be protected, a fluid mixture of aminoplast resin powder and water and leaving the resin to gel on the spot, thus forming a continuous insulating lining coating.