Retreat Mining - checklist

WHEN performing pillar recovery mines should use the below risk factor checklist.

Donna Schmidt

Primary local stability risk factors:

Cut sequence: Is an outside lift sequence being used?


Final stump: Is an adequate final stump consistently being left in place?


Support: Are mobile roof supports being used?


Roof bolts: Is extra roof support used in intersections?


Global stability risk factors:

Pillar design: Is the ARMPS SF adequate to prevent a squeeze?


Collapse prevention: If the ARMPS SF less than 2.0 and the pillar w/h less than 4.0, either on advance or in the worked-out area, have steps been taken to prevent a massive pillar collapse?


Barrier pillar design: If the depth of cover is greater than 1000 ft, are stable barrier pillars (SF greater than 1.5 to 2.5) being used to separate the panels?


Other risk factors:

Roof geology: Is the roof at least moderate in strength?


Intersection span: Have entry widths and turnouts been minimized?


Multiple seam interactions: None anticipated?


Depth of cover: Less than 650ft?


Block size: Are the blocks uniform in size?


Age of workings: Is the development less than 1 year old?


Continuous haulage: None?


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