This paper presents a new method for the objective estimation of mine ventilation system parameters from field measurements. In particular, the problem formulation, solution algorithm, and post optimality analysis are discussed. The problem solved in this paper is referred to as the mine ventilation parameter adjustment problem. It is a minimization problem using a weighted least squares best fit criterion and obeying the physical laws of conservation of flow and energy. The overall efficiency of the algorithm is exemplified by the fact that a ventilation network with hundreds of branches and thousands of measurements can be routinely adjusted on a microcomputer.