The present invention provides a method and apparatus or system for determining an amount of coal tar that can enter, and subsequently be displaced from, a given type of soil for a range of depths of the soil. The method and apparatus also provide verification of the pressure at which coal tar can be...http://www.google.de/patents/US7393689?utm_source=gb-gplus-sharePatent US7393689 - Method and apparatus for characterizing coal tar in soil
