Electrical liner integrity survey the earth below the geomembrane. The leak detection equipment features an ammeter in series with the applied potential circuit. The ammeter registers an increase in current in the presence of a leak, resulting in an audible tone and visual increase in the current level. The expected minimum sensitivity of the water-based bare geomembrane liner integrity methods is a one millimeter diameter circular leak. For the arc testing method, water is not required. A low voltage is introduced above the geomembrane and grounded to the conductive layer below it. In the presence of a hole, an electrical arc is formed along
Coal measures Coal measures The coal measures is a lithostratigraphical term for the coal-bearing part of the Upper Carboniferous System. The Coal Measures Group consists of the Upper Coal Measures Formation, the Middle Coal Measures Formation and the Lower Coal Measures Formation. The group records the deposition of fluvio-deltaic sediments which consists mainly of clastic rocks (claystones, shales, siltstones, sandstones, conglomerates) interstratified with the beds of coal. In most places, the coal measures are underlain by coarser clastic sequences known as Millstone Grit, of Namurian age. The top of the coal measures may be marked by an unconformity, the overlying rocks being