Natural borehole deviation is the inevitable process taking place during rotary drilling. However in case of rotary drilling the deviation is significantly lower than  during calyx boring or hard alloy drilling. That is the reason why industrial workers and even researches believe the diamond borehole deviation has a different nature and thus mathematical formulation methods of the borehole deviation based on calyx boring pattern are not acceptable for the diamond boreholes.In this paper mathematical formulation method of the borehole deviation created earlier is shown to be suitable for the diamond boreholes by example of two gold ore deposits. It is demonstrated that the accuracy of statistic dependences obtained by using this method depends only on the stability (homogeneity) of the drilled geological structures even in case of 200 – 250 meter boreholes.