Prospecting an Outcrop

In most cases the prospector will need to use the digging tools he had used most on the tracking search. Some of these tools include the posthole digger, spade and auger. If these do not work, or if the pick and shovel does not work well either because of the resistance of the hard earth, then the most practical and fastest way is by trenching.

This method was brought in by the Cornish miners and is known as “costeaning”. The main idea of it consists of digging a narrow ditch at right angles to the down slope movement of the heavy mineral. The ditch is started at the most likely area and is dug for several feet in each direction. There are predetermined spots that then get sampled every so often (these distances are usually of around five feet). As soon as the colors can be located and have been picked up, the hole or the ditch is then made bigger at this certain area in order to try to find the outcrop.

If the prospector is not able to find any evidence of hard rock lode while searching, and if the material is quite well cemented but still brings up a good amount of color, there are two different possibilities this is occurring.

To begin with it could be that this consists of residual or alluvial placer that had been buried under the overburden. If this just so happens to be the case, it is likely that it is the residual of an outcrop that has leached out and it may be all that is left. If this were to occur it could be that the area is very rich and it could be a good place to work by hand. When the hard rock area of the vein is reached the rock might not have enough gold in it to support any kind of commercial mining and it could be simply too costly for the average miner to work on and get out.

If a prospector has seen that his discovery is a buried alluvial placer, this would then probably point to that further on up the hill there is probably a residual or at least a rich outcrop that has been buried maybe deeper. If a lot of test drilling or a geologists report it may not be possible to find the original source of the gold. As a matter a fact this might not even be there at all and it may have become eroded many years ago.

There are certain areas such as in California in where it is possible to find a hidden placer located in a lode search that is the channel of an ancient river. This type of deposit can be very extensive and cost-effectively reasonable to promote. These types of deposits can also be found in the West but they cannot be worked on anymore because of the restrictions against hydraulicking. Nonetheless, a good section of this kind of placer might be found during a lode-prospecting search that would be a good idea to work on by hand.