BLM Runs Check on Assay Services
May 2003 by Scott HarnThe Bureau of Land Management (BLM) recently conducted a multi-year study of sixty-five assay laboratories to determine the accuracy of their testing procedures. The laboratories, all located in North America, were provided with ore samples of known concentrations without benefit of identifying the source as BLM. Payment was rendered for the service provided.
Most laboratories involved were sent 4 samples containing known values of gold, silver, platinum, and palladium, and 2 samples that were complex blanks. Prices charged for assay services varied from $60, for fire assays, to $2,250 for a “tin fusion method.” In our review of the report, price did not seem to be reflected as a determining factor for accuracy. In some cases, a lower cost for service provided a more accurate assay.
The results of assays conducted are compiled in a 34-page report, including 16 pages detailing the reasons for and methods used in the study, and 18 pages of results. The volume of the report does not allow for inclusion in this publication, but ICMJ’s Prospecting and Mining Journal has made the entire document available free on our web site:
Study preface (.pdf file) 0.8MB
Study results (.pdf file) 1.0MB
Many of the results published were well within acceptable limits, but some were so far out in “left field” that utilization could be disastrous. Substantial quantities of precious metals were reported in some blanks. Some samples that contained valuable quantities of precious metals were reported as “none detected.” As a result of this report, several assay labs were barred from advertising in our publication.
BLM should be applauded for conducting this badly needed study, and hopefully they will continue this public service. The resulting report should be a valuable tool as a validation for assay services.
When I was a student in the College of Mines at the University of Utah, the Verde district was used as an exploration model for “submarine volcanogenic massive sulfide deposits.” So I looked forward to visiting this district and the town of Jerome in central Arizona in the spring of 2012.
We started planning for this trip last year, after we left Ganes Creek, Alaska, and headed back to civilization. I found 4.75 ounces of very nice nuggets and the group had a total of 47.47 ounces for the week.
I am learning more about gold deposition in this area than I knew previously. I am passing this information on with the hope that many of you will be able to locate patches and lines a little easier in the future because of this article.
Congressmen Richard W. Pombo and John E. Peterson’s Response to Planting of False Evidence by Environmental Extremists
The story begins in the early 1940s in Vance County, North Carolina, on a farm that belonged to the Hamme family. During spring plowing in 1942, one of the brothers accidentally plowed up an odd looking rock and took it home to show his younger brother who was studying geology at Duke University.
The next morning, I retrieved the compressor and again attacked the sticky head bolt. As if by magic (and some applied physics) the head bolt sighed and finally broke loose.
Q: Our group has found a nickel deposit in the Yuma, Arizona area that is similar to the one that you wrote about...
The Ball Mill • Our Readers Say • WMD Raffle Raises Funds for Lawsuit • Gold in Alabama • From the Editor • Yukon Placer Miners Fighting Extreme Discharge Limits • Picks & Pans: Red Beryl Mining—Beaver County, Utah • The Investigation • A Gold Detector Sitting in a Closet Only Finds Dust—A Potpourri of Detector Tips • Central Coast Ranges • Poll: Montana in Favor of Repealing Anti-Mining Initiative • Platinum in Laccoliths • Mining Stock Quotes and Mineral & Metal Prices • Looking Back • Melman on Gold & Silver