The UNIDO methodology for the evaluation of investment projects has been improved. A new parameter of economic efficiency (effectiveness) was proposed, which allows not only to uniformly assess the efficiency of investment and efficiency of financial activities of enterprises of the mining complex, but also to quantitatively assess the investment attractiveness of land deposits development. The new parameter became the starting point for the development of a series of methodological recommendations that represent the basis of the system of business planning for the development of land deposits, including methodological recommendations on the assessment of the cost of deposits, on the assessment of investment attractiveness of deposits, on the preparation of investment proposals, on the development and examination of business plans of investment projects, on the assessment of financial activities of enterprises.