A quantitative technique was conducted at Rosh Pinah Zinc mine, Namibia with its main purpose to determine airways resistance which is a function of the parameters; roughness of the airways and the friction factor. The 32 branch points (i.e. a-ag) that stand for ventilation circuit have been selected. Data collected includes, length and width of airways, air velocity; air density, and roughness of the airways which were used to determine coefficient of frictions, friction factors and airway resistances. A ventilation model was developed. In order to improve the current ventilation model, airways resistance of the mine was determined and simulated in a modified model using VentSim TM software. An average total airways resistance of 0.32027 Ns 2 /m 8 has been achieved for Rosh Pinah mine. It should be pointed out that, as the mine advances its production faces deeper, this value would increases suddenly. Simulation revealed that as much as 34.4 m 3 /s of air can be received at the production faces, compared to the measured received amount of 19.3 m 3 /s. Therefore, volumetric efficiency of the mine was improved from 29.3% to 68.3%. It was also noticed that after importing the resistance values into the model together with other parameters, the model was greatly improved and no cause for concern.