Poraaminen

Poraaminen is the process of creating holes in solid material, most often rock or soil, by means of a rotating drill. In Finnish usage, poraaminen covers a range of activities from exploration and sampling to production drilling in construction, mining, groundwater extraction, and geothermal projects. The aim is to reach a target depth, retrieve material samples, or enable installation of wells, conduits, or foundations.

There are several drilling methods. Core drilling uses a hollow bit to recover cylindrical rock samples for laboratory analysis. Rotary drilling employs a continuous cutting action with a drill bit and often uses drilling fluids to stabilize the hole and transport cuttings. Percussion or hammer drilling relies on impacts to break rock, typically for faster advance in hard ground. Auger drilling uses helical screws to remove soil and is common for shallow, large-diameter holes.

Equipment and systems involved include a drill rig that advances the drill string and bit, and a circulation system to clear cuttings, which may be air, foam, or drilling fluids. Depending on the project, casings or liners are installed to stabilize the borehole, and temporary or permanent anchoring or grout may be used to secure structures or surround wells.

Applications span geological and hydrological investigations, mineral exploration, construction foundations, water supply wells, environmental boreholes, and geothermal or heat-pump wells. Safety and environmental considerations require planning, permits, and adherence to standards to manage risks such as ground instability, groundwater interactions, surface disturbance, and fluid management.