Geophysics is really just a high tech and specialized way of sampling. Rather than sample hard, touchable things like rocks and dirt you can also sample invisible things like electrical currents and magnetic responses. Remember earlier on I said that minerals have a lot of different properties including their ability to conduct electricity? These characteristics can actually be measured which is like saying they can be sampled. Its all very mysterious and cool actually. What petroleum engineer has not listened to a scintillating discourse from a geophysicist showing how the seismic reflective wave has hit the Laburnam Formation and changed direction as it passes through a zone of high porosity. Obviously there is a reservoir in this area. Everyone in the room nods their head sagely and says things like “hmmm uhmm”. And everyone in the room is in a panic thinking. “Am I the only one who thinks it just looks like a bunch of squiggly lines?” The geophysical tools used in mineral finding is much the same. Instead of undecipherable squiggly lines there are undecipherable patterns of pretty colours. Instead of the Laburnam Formation the geophysicist will point to the map and say, “So over here you can see how the Reallybig Fault has ended the conductivity of the signal and turned it back onto the sulfide zone resulting in a hot spot shown in .... red.” And everyone looks knowledgeable and thinks “Huh?”

The collection of geophysical data is left to experts who can afford the expensive equipment and enjoy spending hours outside in rainstorms shooting electrical currents into the ground so that other probes can read the current. I am absolutely convinced that geophysicists are willing to do this because they never tire of watching the bugs jump when the current is injected into the ground. I must say I was fascinated the first time I saw it.

There is a danger in the use of geophysical data however. Because no one really knows what it is saying, there is an inherent danger in being attracted to the red hotspots. Inevitably, when looking at geophysical maps, the question becomes; where should one drill? And equally inevitably the answer comes back - the hotspot. Not because that is the best place to drill - usually it isn’t - but because it just looks so... so... right. It is a very difficult temptation to fight. One might argue that the drilling companies are the owners of the software that create geophysical maps but I have done some checking and it isn’t so.

So now the exploration company has a geological map showing all the rock types and the structures. Based on its soil and rock chip sampling it has found some higher than expected values of gold so a geophysical program was undertaken to develop a map of where the high conductivity rock occurs. All this data is put together and analyzed and darned if it doesn’t look like there might be something there. While the head office guys tell the world that the company is this close to a major discovery a decision must be made on what to do next. The stock price of the company will never be higher than it is right now unless against all odds something is actually found. So now it is time to put up the big dough and drill some holes. This is the point at which well-developed sphincter muscles are a requirement of the job. Drilling is the next topic.