Mining Methods & Machinery

Continuous Surface Mining (BWE Output)

The theoretical output of a bucket-wheel excavator, the effect of fill factor, and converting loose volume to solid in-situ rock.

PART 1

Topic Breakdown & Traps

The Engineering Principle

Continuous surface systems such as the bucket-wheel excavator (BWE) dig without interruption. Their theoretical output is the number of bucket discharges per minute times the bucket volume — converted to per hour. Real output is reduced by a fill factor. Because dug material bulks up, the loose volume divided by the swell (bulking) factor gives the equivalent solid (bank) volume actually removed from the face.

The Core Formula Matrix

Loose output:

Q_{l oose} = n \times V_{b} \times f \times 60 [m^{3} / h]

n

= buckets/min,

V_{b}

= bucket volume,

f

= fill factor.

Solid (bank) output:

Q_{so l i d} = \frac{Q _{l oose}}{swell factor}

The ‘IIT Traps’

⚠
Multiply by 60 to go from per-minute to per-hour output.
⚠
Fill factor reduces output; it's ≤ 1.
⚠
Loose vs solid: divide loose volume by the swell factor (>1) to get the in-situ bank volume.

PART 2

Progressive 3-Tier Question Suite

Q1BASIC1 Mark · MCQ

A BWE discharges

30

buckets per minute, each

0.5 m^{3}

(fill factor

1.0

). Its theoretical output is:

Q2MEDIUM2 Marks · NAT

A BWE makes

40

discharges/min of

0.6 m^{3}

buckets at a fill factor of

0.9

. Its loose output is ______ m³/h. (Round off to the nearest whole number.)

m³/h

Q3HARD2 Marks · NAT

If that loose output of

1296 m^{3} / h

corresponds to a swell factor of

1.2

, the solid (bank) output is ______ m³/h. (Round off to the nearest whole number.)

m³/h