The Situation

A mineral processing plant had experienced ongoing problems with the heat recovery section of their production facility since start-up in the 2000s. This led to partial decommissioning of the original spiral slurry/slurry heat exchange equipment and the phased installation of a vacuum flash system via an initial pilot plant followed by a full scale unit. By 2014 production had been ramped up through both flash units. The full scale unit was processing 70% of production capacity compared to its original design of 50%, with the pilot unit processing the remaining 30%. The full scale unit was performing well but suffering a moderate amount of wear. The pilot plant was experiencing serious wear and had reached end of life.  New sustaining capital expenditure would be needed to avoid significant production losses.

Scope

The client had generated a preliminary in-house concept for the flash heat recovery system. This involved refurbishment of existing and installation of new duplicate plant. Advisian offered to perform a high level review of this concept and was able to identify a substantive value-adding alternative. On this basis Advisian was awarded a Pre-Feasibility Study (PFS) to develop capital (±30%) and operating costs and technical deliverables for Advisian’s proposed alternative concept. 

After a successful PFS outcome which validated the benefits of Advisian’s concept, Advisian subsequently was awarded and completed Feasibility and Detailed Engineering phases for the project.

Our Solution

Advisian was able to avoid the cost of refurbishing existing and installing new duplicate plant equipment through maximizing the performance of the full scale flash unit, allowing it to process 100% of plant production.  Additionally, the solution provided several important opex cost enhancements which:

  • Significantly improved energy recovery
  • Reduced vacuum flash unit downtime / improved operational flexibility 
  • Reduced flash tank wear

Advisian’s solution was estimated to be approximately 30% lower in capex compared to the original solution, and offered a 3.5 year payback on improved energy recovery alone. Additional unquantified benefits included lower maintenance and increased plant uptime.  

On implementation the upgraded system met and exceeded guaranteed performance levels.