A novel algorithm for designing the layout of additional boreholes

- We propose a novel quantitative method for optimal additional borehole design.
- The potential vertical and directional boreholes search with concentric cones around the collars.
- Layout of additional boreholes is dynamically designed based on the objective function.
- The multistage sampling continues until the stopping condition or intended number of boreholes is met.

In an exploration project, the placement of additional boreholes is based on the available information and engineering judgment, which may result in a lack of information or redundant information in decision making. This paper presents the use of dynamic multistage sampling to design directional and vertical boreholes to scan the subsurface. For this purpose, the potential collars of boreholes are determined within the survey area, while the imaginary boreholes in the form of cone sides cover the area's lateral surface area, and the concentric cones around the collars change with azimuth and dip angles. The objective function is a criterion used to determine the optimal borehole(s) and update the input borehole database in each stage; this iterative process continues until a stopping condition is satisfied. The presented algorithm was executed and validated on both synthetic and field data from the Eastern Kahang region in Iran. In the synthetic case, five additional boreholes were designated based on high grade and estimation error objectives that intersect two parts of the ore body. Ten proposed additional boreholes in the northeast region of Kahang coincided with the high grade copper mineralization zone.