Difference between revisions of "Benchmarking: Amelunxen SGI - Agnico Eagle"

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==Design Criteria==
  
==Design Criteria==
−
Actual operating data from Esperanza
 +
Actual operating data, table 7 from the reference
  +
* SAG circuit F<sub>80</sub> = 100 mm
−
* A&times;b of Esperanza ore (Aug-Dec 2012); avg= 39; range is 30.7 to 45.5.
  
−
* Wi<sub>BM</sub> average is 16.0 kWh/st, = 17.6 kWh/tonne.
 +
* transfer T<sub>80</sub> = 244 &micro;m
  +
* circuit P<sub>80</sub> = 74 &micro;m
−
* E<sub>SAG</sub> for "normal" blasting, average = 5.5 kWh/tonne; range is 3.9 to 7.2 kWh/tonne.
  
  +
* SAG power draw (at motor input) = 1350 kW (at mill shell = 1283 kW)
−
* E<sub>SAG</sub> for "high intensity" blasting typically 10% lower E<sub>SAG</sub>.
  
  +
* SAG mill ball charge = 10.6 % vol
−
* SAG feed size range 33.6% to 49.0 percent passing 1&frac14; inch (32 mm).
  
  +
* SAG mill discharge % solids = 84% weight
  +
* SAG mill speed 8.59 RPM (53.4% of critical)
  +
(to achieve DCS power of 1350 kW requires 14% vol mill load)
  +
* ball mill power draw (sum of 2 mills, at motor input) = 1422 kW (at mill shell = 2 &times; 673 kW = 1346 kW)
  +
* ball mill % solids = 83% weight
  +
(to achieve 1422 kW, assume 30% vol mill charge, 17 RPM)
   
  +
Design criteria
−
Design criteria for expansion cases (which may reflect Esperanza operating conditions)
  
  +
* SGI (actually SPI&tm;) of ore (Oct 1, 2000 to - April 30,2001); assumed to be the 25<sup>th</sup> percentile = 24 minutes.
−
* SAG circuit F<sub>80</sub> = 132 mm
  
−
* transfer T<sub>80</sub> = 3500 &micro;m (text erroneously says "3500 mm")
 +
* Wi<sub>BM</sub> assumed to be 10 kWh/tonne.
  +
* Plant availability = 94.4%
−
* BM circuit P<sub>80</sub> = 180 &micro;m
  
−
* SAG mill power utilization = 92.3%
  
−
* Ball mill power utilization = 95%
  
−
* Plant availability = 93%
  
   
 
Mill criteria
 
Mill criteria
−
* SAG mill: 40 foot nom dia by 26 foot flange-to-flange cylinder length
 +
* SAG mill: 24 foot nom diam by 12 foot effective grinding length (EGL)
−
* ball mill: 27 foot nom dia by 45 foot flange-to-flange cylinder length (2 units)
 +
* ball mill: two 11 foot nom diam by 17 foot (assumed to be EGL)
−
* SAG mill gearless motor 31,500 HP (given in Thiele & Parraguez, Relpas 2011 conference)
 +
* SAG mill single variable speed motor 4500 HP
−
* Ball mill gearless motors 25,000 HP
 +
* Ball mill single fixed speed motors 1000 HP (each mill)
  +
* assume rubber liners in SAG, nominal 8½ inch liner thickness
−
(some references give 30,000 HP for SAG motor; this is thought to be the value excluding a 5% design margin)
  
  +
* assume steel liners in ball mills, nominal 3¼ inch liner thickness
   
 
==Modelling==
  
==Modelling==

Revision as of 20:04, 19 May 2015

Benchmarking: Amelunxen SGI Specific Energy Consumption - Agnico Eagle Laronde

Starkey, J., Robitaille, J., Cousin, P., Jordan, J. and Kosick, G., Design of the Agnico-Eagle Laronde Division SAG mill. Proceedings of SAG 2001, pages III-165 to III-178.

Survey conducted shortly after start-up

Design Criteria

Actual operating data, table 7 from the reference

  • SAG circuit F80 = 100 mm
  • transfer T80 = 244 µm
  • circuit P80 = 74 µm
  • SAG power draw (at motor input) = 1350 kW (at mill shell = 1283 kW)
  • SAG mill ball charge = 10.6 % vol
  • SAG mill discharge % solids = 84% weight
  • SAG mill speed 8.59 RPM (53.4% of critical)

(to achieve DCS power of 1350 kW requires 14% vol mill load)

  • ball mill power draw (sum of 2 mills, at motor input) = 1422 kW (at mill shell = 2 × 673 kW = 1346 kW)
  • ball mill % solids = 83% weight

(to achieve 1422 kW, assume 30% vol mill charge, 17 RPM)

Design criteria

  • SGI (actually SPI&tm;) of ore (Oct 1, 2000 to - April 30,2001); assumed to be the 25th percentile = 24 minutes.
  • WiBM assumed to be 10 kWh/tonne.
  • Plant availability = 94.4%

Mill criteria

  • SAG mill: 24 foot nom diam by 12 foot effective grinding length (EGL)
  • ball mill: two 11 foot nom diam by 17 foot (assumed to be EGL)
  • SAG mill single variable speed motor 4500 HP
  • Ball mill single fixed speed motors 1000 HP (each mill)
  • assume rubber liners in SAG, nominal 8½ inch liner thickness
  • assume steel liners in ball mills, nominal 3¼ inch liner thickness

Modelling

The Bond/Barratt SABC-B model is used with the default 10% Essbm calibration factor.

  • circuit F80 = 132 mm
  • circuit P80 = 180 µm
  • The average ball mill work index given as 16 kWh/short ton = 17.6 kWh/tonne
  • The relationship between A×b and WiRM for Andean copper porphyries can be used to determine the following rod mill work index values.
    • A×b of Esperanza ore; avg= 39; becomes WiRM=14.5 kWh/tonne
  • No crushing work index is given. Assume a value of 12 kWh/tonne (slightly higher than typical porphyry)
  • No ore density is given. Assume similar to Los Bronces, density=2.64 t/m³

SAG mill is modelled using following:

  • Austin model
  • assume ore density 2.64 t/m³, same as Los Bronces
  • nominal diameter 40 foot, effective grinding length 26 foot (deduct 2 ft from cylinder length)
  • assume 6 inch liner effective thickness, mill speed 75% of critical
  • ball charge 16% v/v; total filling 26% v/v gives the desired 92.4% utilization of motor power

Ball mill is modelled using following:

  • Nordberg wet overflow model
  • assume ore density 2.64 t/m³, same as Los Bronces
  • nominal diameter 27 foot, effective grinding length 44.5 foot (deduct 6 inches from cylinder length)
  • assume 6 inch liner effective thickness, mill speed 75% of critical
  • total filling 30% v/v gives the desired 95% utilization of motor power

Results

Result for default Amelunxen SGI SAB model conditions:

Esag Epeb Ebm Etotal t/h
Predicted -
Survey -
Difference -
Difference -
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