Gold Samples and Placer Evaluation (Part 2)

(There's gold in this ground...using trusted sampling methods can tell you how much.)

Here's the second installment in my series of posts on placer gold sampling and valuation and in it I'll be directing my attention toward placer evaluation methods, including the block and triangle methods, so read on.

Block Method

In the block method, placer samples are taken from test pits having the same lengths, widths, and depths. These "blocks" can be quite small or they be large really doesn't matter as long as the blocks are uniform across the board.

Gold Panning Kits
Mining Equipment
(Let me know if you find the following confusing, as one reader did. I took this material straight from a good source but my "translation" may be the culprit here.)

Anyhoo, here's what I made of the block method:
  • First, determine the volume of each block by multiplying the length times the width times the depth.
  • Next, multiply the volume by the gold values per cubic yard.
  • Use the sum of the gold values as your "total" value.
  • Find the AVERAGE VALUE of your ground or claim by dividing the TOTAL VALUE by the TOTAL VOLUME of your gold ground or claim per cubic yard.
This is pretty straightforward and you don't have to be a math wizard to use this method.

Triangle Method

The triangle method is just dig or drill three holes in an equilateral triangle with the holes forming the point of each part of the triangle.
  • The triangle's volume equals the average depth of each hole times the area of the triangle.
  • Average gold content for the triangle is equal to the gold values taken from each hole times the depth of the three holes divided by the total depth of the three holes combined.
  • The total volume is equal to the sum you derived in the first step.
  • The total gold content is equal to the total volume times the average you derived in step two.
  • The average gold valuation you can expect equals the total gold content from step four divided by the total volume in step three.
It's as simple as that (just kidding...the triangle method is a bit more complicated than the block method...for me at least).

Worth the Time, Money, and Effort?

I know some of you are sitting there scratching your heads, but if you're deadly serious about making money from placer mining then these methods are proven ways to determine if the expected gold values you'll get are worth the time, money, and effort.

 (Block test pit.)

Don't believe me? That's OK, but just take a look back at some of the TV gold mining crews you're familiar with from the Discovery Channel. If those bonehead wannabes had done systematic sampling up front, they'd have saved boo-coo money and gotten good gold much quicker.

That's my view, anyway.

If you liked this post, you may want to read: "Gold Sample Values and Placer Evaluation (Part 2)"

(c)  Jim Rocha (J.R.)  2013

Questions? E-mail me at


  1. Pretty straight forward J.R......just remembering the geometry and algebraic formulas for volume. Now I don't know how many old-timers were "book learners"....but for larger scale mining...and "real" scale size placer operations...this is a must! Thanks for the installment!

  2. JR, sure sounds like the way to go to me. Of course it's still a guess on the ground you don't dig, but it's a much better guess and a place to start. Bought some new hip boots today, just waiting on the snow to melt so I can get up the mountain....Thanks again, Gary

  3. Thank you for commenting...I'm glad it made sense...I actually was a bit confused with the process when I researched it. But you are obviously an intelligent and discerning miner! J.R.

  4. Keep me posted how things go when you get out and about Gary. Thanks for commenting, as always. J.R.


Post a Comment