Review by Ed Quillen
Mining History – September 2002 – Colorado Central Magazine
Mining Among the Clouds – The Mosquito Range and the Origins of Colorado’s Silver Boom
by Harvey N. Gardiner
Published in 2002 by the Colorado Historical Society
ISBN 0-942576-40-3
Leadville’s great silver boom of 1877 certainly happened in thin air, but it didn’t spring from thin air — even if it sometimes seems that way in our histories.
As the usual story goes, an enterprise was building a flume to bring water to a placer operation near Oro City, the 1860 mining camp that sprang up along California Gulch. The ditch kept getting clogged with heavy black sand, and eventually somebody got around to getting it assayed. It turned out to be rich in silver, and the rush was on.
But as Mining Among the Clouds explains, this discovery was hardly an accident. Experienced prospectors knew just what they were looking for on the west side of the Mosquito Range, for there had already been rich discoveries high on the east side, over in Park County near the summits of several 14ers: Lincoln, Cameron, and Bross.
Because the geology of the Mosquito Range is complex, it took the prospectors a while to discover that the same silver-rich formation sat on the west side, too, but about 3,000 feet lower, since the Leadville side of the fault had not risen as much when the Rockies took form millions of years ago.
The silver ores occur where gray porphyry sits atop blue limestone. Millions of years ago, hot water bearing dissolved silver compounds rose up through the limestone, which water can penetrate and dissolve. Then it hit the porphyry and could rise no more, so it spread through the limestone and silver ores replaced the soft rock.
Geologists call this a “replacement deposit,” and it was pretty easy to understand the process, thanks to Gardiner’s clear writing. It wasn’t so easy to understand in the early 1870s. The ore came in pockets, not veins, and the mining laws of the day assumed there would be a vein when someone filed a lode claim. But these clearly weren’t placer deposits, either. And of course, sorting this out enriched some pioneer lawyers.
Park County was the scene of placer mining for gold as early as 1859, but by 1870, those gravels had been worked over pretty well. Population had dropped from 10,600 in 1860 (a third of the population of the territory) to a few hundred before the decade ended.
Daniel Plummer and Joseph Meyers, both experienced mining men, continued to search in the mountains above Alma. In 1868, they found a rich silver outcrop — the first discovery of silver in limestone in Colorado — at 13,600 feet on Mount Bross. That was just the start of the transportation challenge; on account of the primitive mills and smelters in the area, they shipped the ore all the way to New Jersey to get it assayed. Some of it came back at 400 ounces ($528 at the market price then) of silver to the ton, and the excitement commenced.
The ore was rich, but also sporadic, as the miners soon learned. It also sat at an inconvenient altitude — the Present Help (yep, that’s the mine’s name) sat at 14,157 feet, and the lowest was at 13,200. Lightning and snowslides were frequent hazards. Transportation was by pack-burro, and there weren’t enough smelters to provide good local markets for the ore.
Even so, “by 1876 it was clear that there was one fabulous mine [the Moose] and one great mine [the Dolly Varden] on Mount Bross.” Rich as the mines were, though, “the dynamics of the local ore market continued to limp along.”
Profitable mining, as Gardiner explains and documents, is about more than rich ore. The ore has to be milled and refined, and unless that infrastructure is in place, the mine will have to close for lack of a market. One might have evolved in Park County, but the Leadville discoveries of 1877 — made by two South Park veterans — attracted the talent and the capital.
Mining among the Clouds explains a small but influential mining district in a detailed yet accessible way. There’s the geology, of course, but there was also the technology of smelting the ore, along with issues of law and finance, and Gardiner covers them all without getting lost in arcane details.
So even if this book specifically concerns only one small mining district, it’s also a good book about 19th-century mining in general, one that will explain many oft-ignored aspects of the industry that built Colorado. If you’ve got any interest in Colorado’s mining lore, you’ll be glad you read it.
— Ed Quillen