Abstract: To perform the production scale optimization for open pit mine based on economic dynamic assessment and total balance of overall output of ore and waste， the optimization of opencast boundary is combined with the production scale to build the geological database， 3D geological entity model and block grade model of the deposit. Factors such as uneven distribution of ore grade， time of capital arriving and variability of ore prices impacting on the pit boundary optimization and the production scale are comprehensively considered. With the aid of Milawa algorithm of Whittle， that is the dynamic optimization analysis software， the open-pit boundary with high quality and quantity is quickly generated， and the dynamic economic indexes of mines under different boundary are calculated， with the optimal boundary determined. Through simulating the economic operation of mines， the production scale and the mining and stripping sequence of mines are optimized from the technical and economic views. Relying on the application in the Dongjielegele Iron Mine of Baotou Baiyun Obo， the project indicates that the optimal production scale of the mine is 1.3 million t/a. However， under the current market environment， the investment return rate is 7.6%， with high economic risk of mining. It provides a scientific basis for decision-making of mining enterprises.

Key words: Open pit, Pit optimization, Production scale optimization, Whittle software, Milawa algorithm