Instance: w23

mine picture
  1. Contents:
  2. Information
  3. File downloads
  4. Solution files
    1. UPIT
    2. CPIT
    3. PCPSP
  5. References

Information:

Description:
Partial mine (Phase #2 and #3)
Block model:
74260 blocks of size 25x25x20 ft
Precedences computed with a 45 degrees pit slope (8 levels)
4 destinations: Sulfide mill, Oxide mill, Oxide leach and Waste
Blockfile columns detail:
id x y z dest phase AuRec AuFA tons co3 orgc sulf Mcost Pcost Tcost Tvalue Bvalue rc_Stockpile rc_RockChar
Blockvalue computation
UPIT & CPIT: percomputed using column Bvalue
PCPSP: Computed using (AuFA x Recovery x $900 – Mcost – process cost – transportation cost)*tonnage
Process cost $28.28/ton (sulfide mill), $4.30/ton (oxide mill), $1.12/ton (oxide leach) $0.033 (dump)
transportation cost: 0.18 (sulfide mill), $0.22 (oxide mill), $0.20 (oxide leach)
Recovery is equal to column AuRec (sulfide mill), 92% (oxide mill), 62% (oxide leach)
Only sulfide blocks can go to sulfide mill. Others blocks can go to oxide mill/leach (except RCODE does not include "red", "bf" and "ag")
Discount rate = 0.1
Type of Constraints:
C0 Capacity constraint (mine): Total extracted tonnage <= 68M tons
C1 Capacity constraint (sulf mill): Total processed tonnage <= 3.61M tons
C2 Capacity constraint (ox mill): Total processed tonnage <= 1M tons
C3 Blending Constraint (sulf mill): Average sulf <= 4.5 
C4 Blending Constraint (sulf mill): Average sulf >= 3.8 
C5 Blending Constraint (sulf mill): total sulf/co3 <= 1.2 
C6 Blending Constraint (sulf mill): total sulf/co3 >= 0.85 
C7 Blending Constraint (sulf mill): Average co3 <= 1.6 
C8 Blending Constraint (sulf mill): Average otgc <= 0.6 
CPIT only includes capacity constraints

File downloads:

Download the Minelib data format specification.

Solution files:

UPIT

Download: w23_upit.sol
Objective value: 510,973,998
Computed using Hochbaum's pseudoflow algorithm. [*]

CPIT

Download: w23_cpit_gmunoz120723.sol
Objective value: 392,226,063 (LP GAP 2.1%)
Provided by Gonzalo Muñoz, and obtained from the LP relaxation using a modified TopoSort heuristic. [*]
Download: w23.LPcpit
LP relaxation solution (not feasible)
Objective value: 400,653,199
Computed using a modified version of Bienstock & Zuckerberg algorithm. [*]

PCPSP

Download: w23.LPpcpsp
LP relaxation solution (not feasible)
Objective value: 387,693,394
Computed using a modified version of Bienstock & Zuckerberg algorithm.[*]

References:

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