How can I calculate the spacing needed between boreholes?

Short Answer: Use a 1:1.5 aspect ratio.

Long Answer: If you need to calculate the spacing between your boreholes, use the 1:1.5 aspect ratio. The 1:1.5 aspect ratio describes borehole spacing (S):borehole depth (D).


Let's say your borehole depth is 15m on your survey. Since you know the depth (D) you want to achieve, the spacing (S) should be greater than or equal to 1.5, like so:

15/S ≥ 1.5

So in this example, 15/10=1.5. So your borehole spacing should be maximum 10m.