In 1898 when thousands of eager gold-seekers rushed to Alaska and the Klondike, they encountered an obstacle that many did not anticipate: permafrost. Unlike at southern latitudes, the ground in the Far North was frozen all year round, locking the gold in an icy embrace.
The first work the prospector does a new creek is to pan wherever the bedrock is exposed by the action of water. (Bonanza creek was accidentally discovered by Carmack, who panned in this way, and staked without further prospecting.) If, after panning, favourable prospects were found, a small space of ground is cleared and a shaft, usually 3 feet by 5 feet, is sunk to bedrock. When the gravel was reached it was necessary to make a fire on the bottom of the shaft and thaw downwards until bedrock was reached.
Building wood fires was not only inefficient—it used large amounts of wood and only thawed about one foot of gravel in a day. The tunnels quickly filled with smoke and carbon monoxide which burned the miners’ eyes and could kill by asphyxiation.
Another method of thawing the gravel was by boulders which have been heated in a fire. The warm boulders were dropped on the bottom of the shaft and covered with moss or brush. However, in many localities, the muck contained streaks of sand through which the heat is more rapidly conducted, and as a result a portion of the roof may fall down or cave-in.
The Klondike-Alaska Gold Rush inspired much innovation, particularly in the field of thawing. An inventor named Greenleaf W. Pichard tried and failed to use an electric-powered furnace to melt frozen ground; others pumped hot water into and out of their mine shafts. It was by accident in 1898 that led to the widespread use of steam in the thawing process. A Dawson miner named Clarence Berry was using a steam-powered hoist to drag logs up a hill to his mining claim when he noticed that steam spouting from an exhaust hose had melted a hole in a pile of frozen gravel.
Further experimentation led to the invention of the steam point, a steel pipe used to deliver steam deep into the frozen earth. By the following year most of the miners in the Klondike goldfields had begun using rubberized hose to connect steam boilers to lengths of steel pipe, which they then hammered into the earth. Early on there was no hydraulic pipe available, leading some to use old rifle barrels welded end to end. By fastening a bit to the end and employing multiple points at once, miners would thaw and excavate more gravel than ever before.
Large mining operations in the Klondike and Alaska were soon importing boilers that weighed several tons and could power dozens of steam points at a time. The units cost thousands of dollars and were so heavy that a steamboat was needed to deliver them up the Yukon and a bobsled with a team of horses was necessary to deliver them to mining sites. But for the pick-and-shovel miners, who formed partnerships of two or three men, huge boilers were not an option.
Small-scale miners were frequently on the move and needed a thawing machine to sink prospecting holes and to thaw modest amounts of “paydirt” in remote locations. For them the only way was to have a custom boiler built that was light enough to be carried or transported by dog sled. Instead of the barrel shape of traditional boilers, these novelties were small and boxy and received the nickname “doghouse boilers.”
In 1938, the Northern Commercial Company in Fairbanks announced it had designed a boiler weighing 200 pounds that could be carried by two men using poles inserted through sturdy steel loops on the boiler’s housing. A glass water-level indicator and brass pressure gauge made it a high-tech tool for the independent placer miner, and the boilers were snapped up by customers across the region. The package also came with a six-foot steam point, twelve feet of steam hose, and thirty feet of 3/8 inch pipe.
