How To Salt A Gold Mine


One famous example of this sort of unintentional salting occurred at the Ray copper mine in south-central Arizona in 1899. A careless English engineer let his Mexican crew collect samples without adequate supervision. They naturally chipped away at the softest spots. The samples, sent to London for assaying, indicated a bonanza—rock containing five per cent copper, or a hundred pounds of metal per ton. Excited investors built a railroad into the area, erected a mill, and built tennis courts, a golf links, and a polo field to go with houses staffed with butlers who astounded the local populace by serving afternoon tea.

Repeated mill runs on the first 50,000 tons of ore showed that the samples had erred by about two per cent. Within two years the company was bankrupt. More cautious American investors took over the operation a few years later and spent $300,000 to sample the mine. Eventually mass-production techniques and an ore body of over a hundred million tons made the Ray mine one of America’s greatest producers.

As engineers became more sophisticated, so did swindlers. Some bunco artists tamped minute fillings of dental gold into tiny cavities in the rock. Others preferred to paint the face of the ore bed with a solution of gold chloride or silver nitrate, as the case might be, or to squirt the liquid into cracks with a syringe. Another favorite device was to load a shotgun shell with coin shavings and fire the charge at close range against the rock. Enough metal adhered to give high assay values to samples chipped from that face.

But these methods did not go undetected. Suspicious engineers vigorously washed down the rock faces with brush and water, or blasted a foot or so of rock off the face and sampled the freshly exposed ore before a salter could get at it. Frustrated by these precautions, the salters then turned with fresh ingenuity to meddling with the samples themselves.

Gold dust is easily concealed in any kind of tobacco. Doctored quids were sometimes used by the sellers of California placer mines. A man would bite off a chew, chomp it well, and spit into the pool of water he was using for washing the gravel in his gold pan. Inevitably the residue showed colors.

Ashes from the pipes of native women employed on the sluicing operations at the head of the Jaina River in the Dominican Republic salted those alluvial deposits enough to bleed thousands of dollars from a Boston mining concern. Subsequently, an American con man named Ely Dorsey got hold of the same Jaina River field and interested some Philadelphia capital in running extensive boring, panning, and sluicing tests. Values were intriguing—thanks to tiny clay pills, each containing a grain of gold, dropped into the gravel by native workers. No sale resulted, however, because suspicions were properly aroused when five of the workers suddenly disappeared.

Before long, no engineer would allow tobacco users near a place where sampling was going on. Nor were workers allowed to wear their fingernails long. Wax under the nails of one bribed Mexican laborer in western Chihuahua enabled him to transfer tiny flakes of gold from his pockets to some samples, and his employer extracted a down payment on the mine of $100,000 from a San Francisco operator.

Toward the close of the last century, churn drills were introduced for sampling ore bodies hundreds of feet beneath the surface of the earth. A heavy drilling bit on the end of a stem was lifted a few feet by a cable run by a steam engine on the surface. The bit was then dropped back into the hole. The chips loosened by this hammering accumulated in the water that was dribbled into the hole to soften the earth. Every so often the sludge was raised to the surface, dried, and assayed. Engineer C. S. Haley told, in a 1913 issue of the Mining and Scientific Press , of a test hole that he carefully sealed against tampering during nights when the crew was away. Nevertheless, the hole was salted. The swindler did it by sprinkling gold dust into mud that he then smeared onto the cable attached to the bit. The next morning the dried mud jiggled loose as the cable moved up and down; the mud fell to the bottom of the hole and raised the apparent values. But one morning the swindler applied the mud too late. An alert driller wondered why fresh mud was on a cable that had been idle all night. The plot failed.

Salters were unfazed by canvas sample sacks with their wired-shut mouths and lead seals. Sometimes they got hold of the bags before they were used, and sprinkled grains of gold along the fuzzy inside seams. Some managed to take wax impressions of the engineer’s seals, make duplicates, open and salt the sacks at leisure, and reseal them with the counterfeit seals. Or, given the proper circumstances, they would slit the bags open, salt them, and sew them up again.

Refined swindlers occasionally blew gold dust into sample sacks through goose quills, or injected solutions of gold chloride with hypodermic needles. One suspicious engineer, investigating a mine on an island near Juneau, Alaska (selling price: $450,000), demanded that the owners and their men leave the island while he did his sampling. He took his sample sacks to the docks at Juneau and hired watchmen to guard them night and day until a ship arrived that would take them to San Francisco for assaying. During the wait, dudes would wander by on various occasions asking foolish questions of the bored watchmen and now and then poking at the sacks with their walking sticks. Many weeks later the buyers figured out that there must have been syringes in the ends of those canes. By then, however, it was too late. The deal had gone through, and the victims were stuck.