Twinning Definition Twinning is the observed intergrowth of multiple crystals in a symmetrical fashion. This term applies to the examination of rock thin sections, in the field of optical mineralogy.

Mechanical Extraction System Mechanical Extraction System: Per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a Mechanical Extraction System is one of the Active Methane Mitigation criteria for methane mitigation systems in buffer zones and methane zones.  A mechanical extraction system uses machines that remove methane gas from below…

Adsorption “Adsorption” in geology, refers to the attraction and adhesion of the ions or molecules of a solution, onto the surface of a solid.

Runoff (R) The term “Runoff” (R) in hydrogeology and geology refers to the part of rainfall which accumulates on the ground surface and naturally forms into flowing streams.

Cation Cation: In the fields of chemistry and geochemistry, a cation is a positively charged ion. The oppositely charged ion is an anion.

Dilatancy “Dilatancy” is the increase in the bulk volume of a soil substance during deformation. Dilatancy is caused by the change from a close-pack structure to an open-pack structure.