Question

In a bord and pillar panel, the following data are obtained: 
Number of blasting rounds per shift: 8 
Face dimension (m × m): 4.2 × 2.5 
Average pull (m): 1.2 
Specific gravity of coal: 1.4 
Manpower per shift: 100 
The OMS (output per manshift) of the panel, in tonne, is __________ (rounded off to 2 decimal places)}

Hint:

Field estimates can affect OMS. Always cross-check actual output with reported data if discrepancies occur.

Answer 1

Step 1: Calculate the total volume of coal extracted in one shift.
Each blasting round extracts a rectangular block of coal: \[ \text{Volume per round} = 4.2 \times 2.5 \times 1.2 = 12.6\ \text{m}^3 \] For 8 rounds per shift: \[ \text{Total volume} = 8 \times 12.6 = 100.8\ \text{m}^3 \] Step 2: Convert volume to mass using specific gravity.
\[ \text{Density} = \text{Specific Gravity} \times 1000 = 1.4 \times 1000 = 1400\ \text{kg/m}^3 \] \[ \text{Total output (in kg)} = 100.8 \times 1400 = 141120\ \text{kg} \] \[ \text{Total output (in tonnes)} = \frac{141120}{1000} = 141.12\ \text{tonnes} \] Step 3: Calculate OMS (Output per Manshift).
\[ \text{OMS} = \frac{141.12}{100} = 1.4112 \Rightarrow \boxed{1.41\ \text{tonnes}} \]