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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