| Borehole | |
|---|---|
 Building in Beyond Earth | |
| Cost | 500 
|
| Maintenance | 1  Energy
|
| Requires | 8  PurityPlanetary Engineering |
| Specialist slots | None |
| Effect | +5 Production |
| Notes | None |
History[]
Borehole drilling has been used since the Chinese Han Dynasty, when shafts were driven as deep as 600 meters; the deepest borehole on Old Earth before the Great Mistake was the Kola “Superdeep” Borehole reaching 12,262 meters, since surpassed by boreholes on Mars and Ganymede. Once colonial geologists constructed vertical seismic profiles of the numerous canyons on this planet, geo-engineers began studies on drilling deep shafts for various industrial purposes. Drilling heads placed in nearby canyons allowed the settlements to tap depths beyond anything known before. The first deep boreholes were driven to depths approximately 10,000 meters to tap deep aquifers, bringing water to supply increasing domestic and industrial demands. Shallower ones were driven for mineral and petroleum exploration and for scientific purposes. But the deepest are meant to harness the geothermal resources of this younger planet; the potential of near limitless, relatively safe energy for colonial industry gave those settlements founded near canyons a distinct advantage. Temperatures at the core-mantle boundary can reach over 4000 degrees Celsius, and the geothermal gradient is sharper on this planet than on Old Earth, making high-heat energy drawn from canyon boreholes practical and affordable. Narrow diameter boreholes of 1000-2000 meters serve for seasonal thermal energy storage for some settlements, permitting the collection of heat or cold trapped in fluids for later use.