Benchmarking: Bond - Boddington

Benchmarking: Bond/Rowland SSBM model - Boddington HPGR circuit

Sources, SAG 2011 conference

Steven Hart, S., Parker, B., Rees, T., Manesh, A. and McGaffin, I. COMMISSIONING AND RAMP UP OF THE HPGR CIRCUIT AT NEWMONT BODDINGTON GOLD, SAG 2011 paper number 41.

Hart, S., Rees T., Tavani, S., Valery W. and Jankovic, A. PROCESS INTEGRATION AND OPTIMISATION OF THE BODDINGTON HPGR CIRCUIT, SAG 2011 paper number 126

• Primary crusher product (model F₈₀) approximately 160 mm
• Secondary crushing circuit 4×MP1000 crushers, typically using about 60% of power draw
• Tertiary crushing circuit 4×2.4 m by 1.65 m HPGR, each with two 2.8 MW drives
• Fine screen aperture 10 mm
• Ball mill 26 ft diam by 44 ft long with twin-pinion 8 MW drives

Plant survey conducted April 2010. Ore sample was sent to local laboratory (assumed to be ALS Ammtec) gave following determinations:

• UCS 135 MPa
• Wi_C 27.7 (metric)
• Wi_RM 20.0 (metric)
• Wi_BM 14.4 (metric)
• DWi 9.3; A×b 30
• Bond Ai 0.52

Plant operating parameters:

• throughput 1100 t/h per line × 4 lines = 4400 t/h
• secondary crusher specific energy consumption 0.50 kWh/t with product size about 60-66 mm
• HPGR specific energy consumption 1.60 kWh/t
• overall E_crush 2.10 kWh/t
• HPGR circuit product size (T₈₀) 6 mm
• ball mills drawing about 14 MW (assumed DCS, works out to 13.0 MW at mill shell)
• E_ball = 13000 kW / 1100 t/h = 11.82 kWh/t (at shell)
• circuit P₈₀ ranged from 92 to 128 µm (use 100 µm)

Sources, other

AGC AusGroup project fact sheet. Photo of the ball mill bay indicates:

• Mills are trunnion mounted. Simulate with Nordberg wet overflow model.
• Motors are induction, use 0.96 as motor efficiency.
• Mechanical drives include gearboxes, use 0.97 motor efficiency to shell.

CITIC Censa installation list

• mill shell is 44.5 ft long (F:F, use 44.0 ft EGL)

Modelling

Use the Bond/Rowland single stage ball mill circuit model with the HPGR-BM flowsheet.

Circuit model:

• Set the Essbm calibration factor to 0
• Set the crusher product size to 6000 µ
• Circuit feed size 160 000 µm and product size 100 µm

Ball mill model:

• Use the Full Morrell C-model
• Mill dimensions, diameter 26 ft, EGL 43.5 ft
• motor mechanical efficiency 0.97; motor efficiency to DCS 0.96
• Assume 6 inch liner thickness, 1.26 k-factor, 7.80 t/m³ ball density.
• To achieve 14 MW at DCS, assume speed is 73% of critical and load is 27 % v/v