METSIM® The Premier Steady-State & Dynamic Process Simulator
The heap leach module performs mass balances around the heap leach process including chemical reactions, precipitation and evaporation, solids and water inventories, heap drainage and control logic. With the incorporation of the Contouring Module, any heap type/geometry may be accurately constructed, including: on/off pads, dump leaches, valley-fill leaches, etc. Tracking not only ore to the heap but also all solution flows to, through, and out of the heap will optimize the process performance and allow metallurgists to accurately predict future performance and production.
METSIM allows input of several ore types with separate recovery curves for each ore type. Detailed data on the day to day operation of the heap are provided. Comparisons of control strategies, the effects of changing key parameters and the effect of seasonal variations can be evaluated.
Example of a simplified heap leach flowsheet that includes ponds for raffinte, ILS, PLS, and emergency
runoff. Inclusion of ponds in the dynamic model allows for detailed pond sizing and operation.
The Contouring Module allows for accurate construction of any heap type or shape and may be used to directly import topography or heap construction contours from dxf file types or survey data points. METSIM then uses a variety of tools to quickly and simply build a 3-D model of the heap system.
Screen-shot of a dump leach built in METSIM using actual survey data. Each cell
is individually controlled based on stacking sequence and leaching cycles.
As with any simulation, model verification is key to the success of the model. Instrumentation is easily added to any model so that actual data may be plotted against METSIM predicted figures, including cumulative production, raffinate/pls flows and grades, leach cycle detail, reagent consumption, etc.
Model verifications for two separate projects modeled in METSIM. Cumulative production (left) is one of the key figures that the model must predict accurately to add value to the project. Actual gold production (white line) over a span of 6 years compared to the METSIM predicted cumulated production (orange line) clearly shows the accuracy of the simulation. Solution chemistry (right) is also a critical factor in determining plant operating conditions. Actual pls copper tenor (yellow line) over a production period of 5 years compared
to the METSIM predicted pls copper tenor (blue line) again demonstrates the accuracy of heap leach simulation in METSIM.