Dirk Pässler (carbon-drawdown.de) did some back-of-the-napkin calculations for their experiments (enhanced weathering of basalt dust on cropland):

> In the end we calculated the actual emissions to be 44,6 tons CO₂, due to the fact that we drove more truck kilometers than we had planned. This is less than 10% of 1217 t basalt’s CDR potential of 509 t CO₂. In summary: The mining and transport emissions are one order of magnitude smaller than the CDR effect, even with 300-500 km transport distances. This will only get better in the future with more green energy, electric trucks and optimized logistics.

https://www.carbon-drawdown.de/blog/2022-12-14-how-cdr-with-...