Introduction The old adage “Gold is where you find it!” can be taken to indicate that applied exploration methods for conventional gold deposits are becoming increasingly more non-specific and non-productive. New, viable gold discoveries are fast becoming a rare occasion; their consistently lower grade-tenors require larger-scale mining operations in order to maintain a reasonable profitability.
“Hidden Gold” The widespread geochemical presence of a bizarre phase of gold, often termed “hidden gold,” that is very fine grained and, using conventional methods, is difficult to nearly impossible to analyze, has been well known for at least 150 years, and possibly much longer. Only rarely has this “hidden gold” phenomenon been discussed or described in the professional literature. Very likely, most researchers prefer not to be classified professionally as delusional; it is much less stressful to take the conventional, more classical route! One rather outstanding exception follows:
The following statement, published more than 30 years ago by Aurthur F. Daily in the SME Mining Engineering Handbook, recognized the existence of what I have termed "precursor ore." With respect to my research, Daily's conclusion ia appropriate in that the analytical procedure used for assaying is, in essence, a miniaturized or scaled-down version of the production methodology.
"Gold in similar free form, or in organic or inorganic compounds down to molecular size particles, undoubtedly occurs in alluvium. In none of these forms would gold be susceptable to cyanidation, because free particles in alluvium are coated with mineral salt and thus insulated from the solution, and compounds would not react. No reliable method of assay for gold in these forms is known at present. The presence of significant amounts of such gold in certain unconsolidated sediments has been very strongly indicated from recent research. It is expected that a method of extraction will be developed, which may also be the first method of assay. After determination of the parameters, the scientific knowledge acquired undoubtedly will lead to other applications of more importance than extraction of gold." (Italics added). AIME, SME Mining Engineering Handbook, 1973, v. 2, p. 17-158.
As it turns out, Daily’s predictions were amazingly accurate? What should be added, however, is that the remainder of the precious elements, as well as many of the other transition elements, also exist in nature in the same curious form as “hidden gold.”
Atomic Clusters, etc. The concept of naturally occurring, precursor-type, transition elements, especially the precious elements, is discussed in some detail in various sections on this website. This so called “hidden gold” is an example of this precursor-type cluster complex and may be described more specifically as “small gold atomic clusters firmly bonded to amorphous colloidal silica; = au/a.c.s.” Extensive bench and pilot testing clearly demonstrates that au/a.c.s. (hidden gold) responds chemically in a manner similar to precursor-type platinum group elements.
Some Comments on Production Using a combination of heterogeneous catalysis, colloidal chemistry, and heterogeneous nucleation, a production system has been developed that might well come close to mimicking nature. This procedure is rather simple and inexpensive to operate, requires no harsh chemicals (no sodium cyanide, aqua regia, etc.), and is environmentally “green.” At the operator’s discretion, one to all of the precious metals may be recovered from a precursor ore source during a single leach cycle. This makes the economics rather interesting!
The photograph to the right is part of a precious metal product that was derived by processing a cenospheres/fly ash by-product from a western U.S. power plant. This photograph shows the pinkish red final product (in a white bowl) which contains in excess of 25% gold + (platinum). The adjacent small plastic weighing tray contains the parting residue from a standard fire assay of 2 grams of this material with 6 grams of analytical silver as an additional collector; it consists of gold with some alloyed platinum.
So, gold (and the platinum group elements) is where you find it (them); almost everywhere! A.C.J. (11/10/08)
