Mine roof monitoring apparatus

A mine roof monitoring apparatus, comprising;

• a first contact member and a second contact member operatively associated with each other and resiliently biased in an expansive manner;
• and a motion monitoring apparatus attachable to either said first contact member or said second contact member, said motion monitoring apparatus comprising;
• an attaching member;
• a flag mount having an extending end and a base end, said base end of said flag mount being fixed to said attaching member;
• a flag having at least a first end edge and a top edge with a latch receiver on said top edge proximal to said first end edge, said flag being pivotally connected proximal to its first end edge to said flag mount;
• a latch operationally associated with said flag mount and attaching member, said latch capable of engaging said latch receiver to maintain said flag in a first position, and;
• a latch release;
• wherein,
• said first contact member is maintained in contact with a mine roof and said second contact member is maintained in contact with a mine floor by being resiliently biased away from each other, and;
• said attaching member attaches said motion monitoring apparatus to either said first contact member or said second contact member with said latch release in proximity to the complimentary contact member,
• and wherein,
• when said mine roof subsides a predetermined amount, said first contact member moves said predetermined amount with respect to said second contact member, causing said latch release to unlatch said flag from said first position.