Distinctly Montana Magazine

w w w . d i s t i n c t l y m o n t a n a . c o m 81 storage bin at the top of the flotation mill. A now-collapsed tram system also carried ore from the upper tunnels to the mill. The intimidating Portland jaw crusher, comprised of heavy moving and stationary plates, and the ball mill, a cement truck- sized, rotating drum charged with water and forged steel balls, then pummeled the ore into fine grit or pulp. Throughout the latter half of the 19th century, millers extracted precious metals from crushed ore using chlorination and cyanidation. These techniques were effective for leaching out valuable gold and silver concentrates but were unsuitable for processing the more prosaic base metals now in enormous industrial demand in early 20th century America. Equally problematic, most accessible, high-grade ore bodies were de- pleted, necessitating new technologies to effectively process abundant low-grade ore. To the Western mining industry's considerable luck and great fortune, Australian millers devel- oped the froth-flotation process in the early 1900s. In essence, froth-flotation enabled metals to be extracted from pulverized ore in flotation tanks containing water, oil, chemicals and solvents. Conveyor belts carried the ore pulp from the ball mill and rake classifier (a device that separated any remaining coarse material from the fine pulp) to nearby interconnected flotation tanks. Paddles at the bottom of each water-filled tank agitated the pulp in various chemical formulas, causing the desired metals to attach to rising air bubbles. Millers then skimmed off the frothy metal-rich concentrates, and dried, stored and shipped them to local and distant smelters. Work crews pumped the minerals-de- pleted sludge in the bottom of the tanks to convenient places below the mill, usually floodplains, leaving cadmium, arsenic and other heavy metal-laced tailings piles for future generations to clean up. Gold and silver are Montana's signature minerals but base metals are its bread and butter. Look no further than Butte to appreciate the enormous socioeconomic impor- tance of copper. During World War II, zinc produced at Charter Oak and many other mines saw extraordinary demand as a key in- gredient in cartridge brass, rust-proofing iron and steel, dry cells, waterproof paint, rubber manu- facture, cloth dyeing, and a myriad of military-oriented products. Similarly, lead found use in an array of war supplies and alloys. Man- ganese, chromium, molybdenum, and tungsten became critical steel alloys. Tetraethyl lead was a critical component of motor and aviation gasoline fueling America's harrowing ground and aerial warfare in the Atlantic and Pacific theaters. The Western stereotypes of fiercely independent miners and powerful corporate mine bosses overshadow the federal government's gargantuan role in supporting and subsidiz- ing the American mining industry during World War II. Congress first passed the Strategic Materials Act to stock- pile critical war materials. Gold Limitation Order L-280 effectively closed most gold mines by refusing operators access to crucial mining supplies (gold had limited appli- cation in strategic war products). The government offered price supports and premium payments for zinc and other base metals. This enormous financial investment by the U.S. government transformed the West into an expansive war- time workshop, which eventually became part of America's post-war industrial infrastructure. After the war, James Bonner from California became involved with the Charter Oak operation, creating the Char- ter Oak Mining Company with the inveterate miner John Hopkins. Bonner and his wife Esther lived in the old cabin. Despite the pleas of their neighbors, the Bonners refused to dynamite beaver dams, helping to insulate the Little Blackfoot River from the noxious mill tailings piled up on the floodplain below the mine. Charter Oak continued to produce lead and zinc into the early 1950s, but had limited production thereafter. Bonner conveyed his mine interests to John Hopkins and Henry "Hank" Lauri, an Elliston miner, who formed the Hopkins Mine Incorporated. Not much on-site mining was done. In-

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