Correlation of mine surveys with the U.K. Ordnance Survey National Grid

In the U.K. the preparation and preservation of mine plans is strictly controlled by legislation, and every new plan must be orientated to and correlated with the Ordnance Survey National Grid. In order to implement this requirement, the mine surveyor requires a knowledge of the projection system used by the Ordnance Survey and of the computations involved in determining local scale factors, convergence and other variables. The aim of this paper is to explain clearly, approximate and precise methods of correlation, by means of worked examples.