subsurface formations 114 the drill string 108 includes a kelly 116 in the upper portion a drill pipe 118 and a bottom hole assembly 120 located at the lower portion of the drill pipe 118 the bottom hole assembly 120 may include a drill collar 122 a downhole tool 124 and a drill bit 126 the downhole tool 124 may be any of a number of different types of tools including measurement while drilling mwd tools logging while drilling lwd tools etc during drilling operations the drill string 108 including the kelly 116 the drill pipe 118 and the bottom hole assembly 120 may be rotated by the rotary table 110 in addition or alternative to such rotation the bottom hole assembly 120 may also be rotated by a motor not shown that is downhole the drill collar 122 may be used to add weight to the drill bit 126 the drill collar 122 also may stiffen the bottom hole assembly 120 to allow the bottom hole assembly 120 to transfer the weight to the drill bit 126 accordingly this weight provided by the drill collar 122 also assists the drill bit 126 in the penetration of the surface 104 and the subsurface formations 114 during drilling operations a mud pump 132 may pump drilling fluid known.