A second method of sidewall coring is rotary sidewall cores. INTEQ provides directional Drilling, MWD/LWD, surface logging (mud logging) and coring services. After coring, oil flowed to the surface during a drill stem test at . Coring began as a method of sampling surroundings of ore deposits and oil exploration. Although the coring depth was limited, microbes were found wherever the sediments were sampled. Another, cheaper, technique for obtaining samples of the formation is "Sidewall Coring". The MAX-C rover would have been able to acquire samples through coring and abrasion. The investigations at the site have involved both coring and excavations. Coring accumulations of bat guano can be useful in determining past climate conditions. Coring was first discovered by Dr. Aubrey Tang. "Coring and core analysis" is a direct measurement of petrophysical properties. The cracking was caused by an internal coring problem when the blocks were cast. In the coring process, the sample is pushed more or less intact into the tube. One way to get more detailed samples of a formation is by coring. In February 2012 NOV acquired a Russian coring company Interval Ltd.