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10 Ounces of Alluvial & Eluvial Gold from the Bathurst Region of NSW
Firstly lets identify the difference...."Alluvial" gold is gold that has weathered from primary reefs and made its way to either ancient or modern water courses. Within these water courses it is moved by the stream or river and generally ends up on or near the bottom of these streams. Water action on these nuggets tends to erode the edges and as such are generally well rounded having few if any sharp edges.
"Eluvial" gold is gold that has weathered from a primary source and not made its way to a river or stream. It tends to be rough in nature with either sharp edges or a "prickly" formation, with in many cases the host rock still attached....we call these "species" and can quite often be large in size if they have only weathered a short distance from the parent reef. This is the gold that I most like to chase as many small stringer reefs were either missed or not substantial enough for the old timers to bother with. They were chasing the mother loads from large reefs and were extremely good at finding them to the point of very few were ever missed.
Successful detecting for these nuggets on a consistent basis is not a matter of luck and learning a few basics will greatly increase your chances of getting more rattles in your jar. Firstly, understanding how to read a geological map and by that I mean not just looking at rock structures in the areas you are searching. There are many more important things to look for such as "strike" and "dip", sheer or fault zones, uplifts and folding, direction of weathering, and the list goes on. It's worth taking the time to familiarize yourself with these as, when you overlay a topographic map to these areas you can soon establish which streams run through them and which direction they are travelling. These "geo" maps also show areas which have metamorphic zones and when they coincide with a fault zone in a gold bearing area you can very much narrow down where the best spots will be to start your research.
In NSW most of our gold fields tend to be at high elevation and as such make them very desirable for the detector operators who do their homework. Being high in elevation many of the smaller streams and creek beds have long bedrock sections and shallow overburden which makes them prime targets for the better PI machines and operators, as the gold is usually well within reach. Being able to isolate some tell tail signs like distinguishing greenstone from shalestone caused from metamorphic action by heat and pressure is also a good thing to know and learn, as being able to identify these areas will put you closer to the better gold.
Many of these high level gold deposits are also very rich in reef zones and shafts are common on almost every gold bearing area. This is where those who chase "Eluvial" gold can have some very rewarding finds if they can isolate some of the smaller stringer reefs that the old timers didn't bother about, and believe me when I say a very large number of these still exist to this very day. One small such stringer rewarded me with several ounces of rough gold from an area of less than 50 sq. metres from the primary source. They do exist and once you know what to look for, are not that uncommon to come across. My advice to the newcomers is keep well away from the larger shafts as when the old timers loamed their way up to them they didn't miss much. Also these deeper shafts saw a lot of action over considerable time, plus most of the miners camped on or near these shafts leaving huge amounts of accumulated rubbish strewn all over the place. Not fun when detecting. You will find that most of these shafts are in a line and follow fault zones. In my experience searching areas further up from these shafts are the most rewarding, remembering these hills/ mountains were hundreds of metres higher millions of years ago.
Successful detector operators are also the ones that take the time to become one with their machines. Coil selection also plays a big role. Not much benefit in running a large coil in a small stream/creek or a small coil for "eluvial" on the side of a mountain. Pretty obvious you might say but I have witnessed on many occasions wrong coil size has led to negative results in areas where they should have found a nugget. Pulse Induction or similar format machines are a must on our goldfields and will find more than 90% of the gold. VLF machines will find gold but with much less consistency coupled with a big headache from all the ground noise one has to contend with. If you want to be serious about getting good consistent gold, get a minimum of a GPX4500, 5000, 6000 Z7000 or SDC. As with any trade the better your tools the better your outcome.
There is a saying amongst fishermen that goes...10% of the fishermen catch 90% of the fish. The same goes for prospectors and that 10% get 90% of the gold. It is those who dedicate themselves to their craft and learn their trade who eventually become successful. One might say... but you still have to walk over that nugget so luck has some input. To that I say those who know "where" to walk, will walk over many more nuggets in the long run and make their own luck rather than rely on luck itself......may that big paddock be kind to you and may a large proportion of your targets be positive. Cheers Wal.
Below is a video of what type of creeks we tend to look for when chasing NSW alluvial gold.
