The Math of Nugget Distribution (Part 1)
For the majority of small-scale gold miners nuggets are the icing on the proverbial cake. I know in my own four decades of prospecting and gold mining that nuggets are few and far between, especially medium-to-larger sized nuggets. So let's talk about the "rarity" factor of nuggets in both general and math-specific terms.
Not an Exact Science
First off, I'm basing this distribution math on data gathered in Australian goldfields. That may pose a question in your mind that goes something like this: "How can nugget distribution in Australia help me understand how nuggets are distributed here in the United States (or the United Kingdom, South Africa, South America, Mexico, Canada, or anywhere else in the world?)." Well, it's my contention that nugget distribution and/or rarity Down Under provides a solid basis for comparison elsewhere in the world including the U.S. One reason for this is that Aussie goldfields have been highly prolific in producing placer nuggets, including many exceptionally large ones. In fact, Australia ranks at the top when it comes to overall nugget recoveries, both historically and in modern times. The second reason is that the Aussies have made it a point to collect as much data on gold nuggets as is humanly possible. Now you can accept or reject my premise as you may, but I think it wise to consider it just the same because there is proven comparison data from other countries that supports my premise from a mathematical standpoint, despite differences in gold nugget recovery or production records from country to country, region to region, and area to area. Nugget distribution is not an exact science in Australia or anywhere else, of course. But it does provide a basis for understanding what sort of math is involved when you're out there mining, prospecting, nugget hunting, etc., both here in the U.S. or elsewhere. In other words, nugget distribution data provides a simple, math-based guideline for understanding what you may expect out there in terms of distribution numbers per size of nugget considered.
(A "big one" from the Aussie goldfields.)
One Big Monkey Wrench
So let's stick to placer gold in this nugget context because that's what most of us do and are interested in. Hard-rock mining is a different beast entirely, although at one time or another elluvial nuggets or nugget patches that have eroded out of nearby mine sites, reefs, veins, or blow outs may come into play here. Next, let's include all forms of placer mining and the equipment used therein, including nugget hunting with a gold detector. Finally, for reasons that should be readily apparent we have to include larger-scale or commercial gold mining ventures that move (or at one time moved) tons of material on a daily or weekly basis. That sets the stage for the mathematics of placer gold nugget distribution, OK? It doesn't take a rocket scientist or, better yet, a math whiz to understand that larger nuggets are always rarer than smaller ones. But what many of you may not know is that familiar, and often repeatable, patterns tend to show up in any given gold area known for producing nuggets of varying sizes. Granted, science or math can't account for every variable Ma Nature tosses out when it comes to nugget distribution in a specific area or region, but both of those analytic pursuits can get closer than you might think. Most of the data for this sort of mathematics-driven assessment of nugget distribution comes from 1) historical records, or 2) production figures (both small and large-scale). But let's digress for a moment here. When we think of commercial or large-scale placer mining operations today we immediately think of huge excavators, skip loaders, hauling trucks, huge wash plants, etc. In the past, however, a large-scale operation could've been a small group of miners banding together to divert a stream with a flume to get at bedrock or a "company" of Argonauts using cast-iron or brass "monitors" to wash down hillsides in hydraulicking operations. There were probably many other larger-scale many variants like these applied in the past as well. So we have to mix together the old and the new when it comes to nugget-related data extracted from known production records. If there is one big monkey wrench in the nugget math distribution data, it is the fact that many very large nuggets recovered by the old timers were simply melted down and sold for weight value, not as specimens. Additionally, many smaller-sized nugget finds in the old days were not even recorded. So we have to take these factors into account as well when it comes to nugget distribution. Lastly, we have to remember that we're talking solely about placer nuggets here, whether alluvial, elluvial, eolian, etc., and whether those specific placers were wet, semi-wet, or bone dry (desert or in arid regions).
(Commercial mining operations [small or large] also count in gathering nugget distribution data.)
Now I want you to consider something. None of this nugget data or math distribution stuff is going to apply to you if you are working a gold area that's NOT known for producing nuggets. Some gold areas here in the U.S. are known only for producing fine gold or flakes with no known or recorded nugget finds. So applying nugget distribution projections to areas like this is simply pissing into the wind. It won't do you a damn bit of good, to put it even more bluntly. Next we have to understand the subjectivity involved when it comes to defining exactly what a nugget is. The old-timer's standard here in the U.S. was (and remains) any single piece of placer gold that is as large as the tip of a wooden kitchen match head. Now that's a very small nugget to be sure, but it does provide a general starting point for recognizing what a nugget is here in the U.S. My very first nugget find was this size/dimension, by the way, and I still consider that find my "first nugget." Elsewhere throughout the known world (including Australia) this minimum nugget standard may be different and based not on size, but weight. I really don't know or particularly care, for that matter. We just need to establish that nugget standard for the the U.S.
(Is the smaller one a nugget?)
OK, enough of that.
So now I've set the stage for you. We'll move on to some real facts and figures about nugget distribution in my next post. (Notice how I left you hanging here!?)
Until then, hang tough and don't let the bastards grind ya down...
(c) Jim Rocha 2018
Questions? E-mail me at firstname.lastname@example.org