Miners usually work in very hot, dusty, conditions which are far from the surface of the mine. If they wanted water they would have to bring it to their place of work in some sort of container. This particular example is a plastic 'jack' from the mid - 1970s which was sold in all colliery canteens.
To view this item in 3D, click: http://labs.casgliad.sequence.co.uk/water-jack.aspx