You're the blaster-in-charge. Read the rock, set the pattern, load the holes, and shoot. Match the powder factor to the ground, keep your stemming honest, and never — never — put rock over the highwall. Five shots per shift.
SHOT 1/5TONS BANKED 0BEST SHIFT 0
ROCK: MEDIUM DOLOMITETARGET PF ≈ 1.10 lb/CY
BENCH 40 FT · SUB-DRILL 4 FT · 6-3/4" HOLES · 11 lb/ft
⚠ FLYROCK OVER THE WALL
POWDER FACTOR —S/B RATIO —STEM/B —
The physics: powder per hole = (bench + subdrill − stemming) × 11 lb/ft. Powder factor = pounds ÷ (B×S×40/27) cubic yards. Harder rock wants a higher PF. Sweet spots: S/B near 1.25, stemming near 0.8×burden. Short stemming = flyrock and a call from MSHA. Long stemming = boulders off the top. Bigger patterns bank more tons per shot — if you can still break them.