CaseStudyForm | |||||||||||
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Title | The Forestry (Logistics) Problem | ||||||||||
DateSubmitted | 3 Apr 2008 | ||||||||||
CaseStudyType | DIYCaseStudy | ||||||||||
OperationsResearchTopics | LinearProgramming, IntegerProgramming, NetworkOptimisation, TransportationProblem | ||||||||||
ApplicationAreas | Logistics | ||||||||||
ProblemDescription |
Adapted from a real-world problem
A paper company own a number of mills that produce paper with different processes, e.g., the thermo-mechanical process (see Figure 1), the cold caustic soda process, etc. They procure raw materials for each of their processing machines from a number of different suppliers.
Figure 1 Thermo-mechanical Processing Machine
![]() Process (TMP) | Refiner-Mechanical Process (RMP) | Stone Groundwood Process (SGW) | Cold Caustic Soda Process (CCS) | Recycled FibreM Process (RCF) | | ||||||||||
Kawerau | yes | yes | yes | no | no | ||||||
Boyer | yes | no | no | yes | no | ||||||
Albury | yes | no | no | no | yes |
**Thermo-Mechanical** | **Refiner-Mechanical** | **Stone Groundwood** | **Cold Caustic Soda** | **Recycled Fibre** | |||||||
**Mill** | **Process (TMP)** | **Process (RMP)** | **Process (SGW)** | **Process (CCS)** | **Process (RCF)** | ||||||
Kawerau | 10 | 15 | 52 | - | - | ||||||
Boyer | 15 | - | - | 10 | - | ||||||
Albury | 20 | - | - | - | 22 |
The transportation cost of the raw materials is given in the following table: <p
Note that pulp logs can be "chipped" into woodchips at the suppliers at a cost of \$250/tonne and that waste paper can be "compacted" into woodchips at the recycling plant at a cost of \$600/tonne. Any excess waste paper that is not used must be disposed of at a cost of $150/tonne.
The paper company want to know how to supply their mills at minimum cost. They also want to know how much "streamlining" their processes (i.e., reduce the amount of raw materials they use) will reduce their overall transportation costs. For more detail see Supply Chain Optimisation in the Paper Industry, Philpott and Everett