Base metals prospecting
Base metals are abundant in New Brunswick, although base metals are often associated with gold and other precious metals they are mined or prospected on their own. Typically these deposits contain a higher grade ore combined with a greater tonnage estimate than gold mines or other rare earth mines. Base metal prospecting is actually an excellent foundation for individuals learning to prospect. You will find that while looking for gold or other metals you often have to learn about indicator minerals or associate minerals to help locate the more precious metals. These indicator minerals are often in the base metal category and offer a very diverse range of combinations or presentations in their natural environment. Lets start with some of the more basic base metals.
Copper - Can be found in it's native form in nature however it is more often found combined with other minerals. Copper can be found in several forms which I will list below.
1. Copper Sulfides - Chalcocite, Chalcopyrite, bornite, covellite, digenite
2. Copper Carbonates - Azurite and malachite
3. Copper oxides - Cuprite
These are just a few examples of the many minerals where copper is found. Note though that not all of these occur in economical concentrations of copper, however being able to identify these minerals certainly helps.
Copper-Gold Porphyry deposits - These deposits form deep within the earths mantles, often several kilometeres beneath present levels before coming to the surface as orebodies. Hydrothermal fluids and meteoric waters create chemical reactions which concentrate these mineral rich fluids into orebodies or stockworks. Often these deposits are large in nature and are associated with intrusive rock formations. Porphyry dikes are one of these associated formations. Copper porphyry often contains low amounts of gold however can be mined soley for the gold content in some situations. Below I will provide a couple of photos of Porphyry ore under the microscope. This ore is a copper gold porphyry.
Above - Copper ore from Saint Martins area N.B.
This photo is courtesy of www.leafandstone.ca who worked in conjunction with local prospector Robert Murray on his discovery of a large copper deposit.
Chalcopyrite
Chalcopyrite is a copper mineral but has the potential to hold many other minerals including but not limited to: Silver, gold, cobalt, cadmium, nickle, antimony etc. Chalcopyrite can sometimes be confused with gold to the untrained eye however there are a few distinct features which can help you identify it. Chalcopyrite has a hardness of 3.5 to 4 on the mohs scale and will have a greenish streak when rubbed on unglazed porcelain. Also chalcopyrite will often need light to see it's full metallic lustre where as gold can be seen even in low light conditions. Chalcopyrite will often also oxidize to have a rainbow like sheen, Once again I have a couple of photographs to show you what chalcopyrite looks like, under the microscope.
