Design is the art of applying the principles of science in formulating practical solutions to real-life problems. Design is the act of coming up with a cost-effective way to build and operate a physical structure, whether it be a bridge, a building, a tailings impoundment, a heap leach pad, or an access road to the new mine. Design is an act of creation; a good design comes seemingly out of nowhere; yet a good design comes from everywhere, being a reflection of past practice, knowledge, understanding, calculation, perspiration, inspiration, and judgment.
The word “design’ however has two distinct meanings, however. The first is the act of creation I refer to in the paragraph above. The second, more common meaning is the set of calculations, specifications, drawings, and a design report that documents the creative act. Both the act and the documents are important; both should be interwoven into a seamless process.
I wrote these word some while ago. I was reminded of them when I recently looked at the layout for the diversion ditch around a proposed heap leach pad. In a mere mile of length, it meandered like a contorted snake across the landscape through deep cuts and over impossible fills. It looked wrong. I asked its designer, a young fellow, but two months out of colleague about its design.
He proudly told me he had made the base width 6 meters so that the 100 year precipitation runoff would sheet flow down the channel. What is the grade of the channel, I asked. He told me some impossible low number–one of those inclinations where water delays and ponds. I asked him how the channel would perform in the one year storm and the two year storm and so on.
“I don’t know,” he replied, “They told me to design for the 100-year storm. I have not looked at lesser events.”
I reminded him that in lesser events, which obviously occur with greater regularity, that in practice, sand bars and banks would build up and vegetation would grow in the moist soils. Take a look at the outlet channel from the Santa Ana River between Huntington Beach and Newport Beach if you doubt me. And then when the 100-year runoff came along it would find a choked channel and would overflow the banks.
He grinned sheepishly, scratched his head, and promised to go back to the drawing board. I hope he does.
Right now I am dealing with a mining client who is a scientist by training. He is trying to get his head around the imprecision yet demand for accuracy of design. As a scientist he seems to believe we must set up a perfect numerical replica of physical reality before we design or build. If he would pay me to do 3-D analyses with a fast computer, we could move in the direction of a replica of perfect reality. But in practice ,we do 2-D analyses and thus limit our ability to perfectly replicate reality. In fact we even arrange our design so that we are able to analyze what we build with 2-D analyses. Regardless, all our analyses are simulations, models, foci on one or more aspect of reality that we seek to understand before we commit to a drawing or a construction program.
No matter; young men will learn, although it will take longer than it took us old men: the young still have to sluff off the illusion that their electronic gadgets can replicate reality. If you doubt the illusions of young men, look at the economy, modelled by so many bright young things with no knowledge of history.