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Computer Modeling for Mines [blog]

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These past two days I have had to deal with that knotty subject, computer modeling for mines.

I proposed a series of 2D runs in order to get a feel for how groundwater flows into an open pit and from the tailings facility.

The younger generation cried in horror at my simplicity. “We need 3D models to truly replicate the situations,” they protested.

I protested: “We are not modeling things on the computer in order to replicate reality and create an electronic simulacrum of what is in nature.”

“Then why are we modelling,” their innocent & ignorant reply.

“In order to understand the system and ask specific questions,” my reply.

The idea of understanding a system baffled them. They see e-replication as the objective–simply enter what is there into the computer, let the computer run, and the truth will out. At least that is how I interpreted their perspective.

It took a long time for me to point out that we had a pretty good understanding of how water would seep from the lake through the fractured bedrock to the open pit, and this understanding came simply from looking at the topography, getting to grips with the bedrock, plus a damn good understanding of seepage and flow net. It took a long time for me to point out that we knew how and where water would seep from the tailings facility for the same good reasons of looking at data and understanding fundamentals.

The smart kid on the block asked: “Then why do you want to model?”

“Because I cannot easily and quickly sketch the flow nets. Yet I need these to quantify seepage rates and need to do a parametric study of different rock and tailings permeability.” I replied. “The computer makes parametric runs easy & quick.”

So they said OK and we proceeded with 2D modelling. We documented our modeling objectives thus:

  • Confirm first concepts of where groundwater will flow.
  • Detail flow paths.
  • Quantify seepage quantities for a range of material permeability.
  • Examine the impact, if any, of cut-off walls, capture trenches, and drains.

They did persuade me to look to 3D models. But only after I insisted that we establish why we were doing 3D modeling. After much discussion, we agreed that 3D models could tell us definitively where the seepage from the tailings facility will go, where we need to concentrate dewatering wells, and where a cutoff trench will suffice.

The point was that the computer modeling is subservient to the needs of engineering design. The modeling is not an objective in and of itself–an attempt to replicate reality in the interests of intellectual bragging.

Hope these stories and ideas help you avoid the terrible expensive route of computer modeling for the sake of modeling and showing off. Let me know, for I am sure I gore some confirmed egos.

This article appears courtesy of I Think Mining. To read more of Jack Caldwell's blog click here.

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