Willoughby: The Assayers of Aspen | AspenTimes.com

Willoughby: The Assayers of Aspen

Aspen Historical Society photo A scale and a furnace for melting ore samples occupy front stage in one of Aspen’s assay offices of the 1890s.

During Aspen’s mining era, assay offices commanded as much main street real estate as boutiques do today. The businesses offered a vital service to the industry town. Assayers worked overtime to evaluate and quantify ore components that ranged from arsenic to zinc.

Before the railroad reached Aspen, prospectors and miners developed a good eye for ore. They had to quickly distinguish profitable, silver-laden ore from stone that would not pay its own way on a mule train to a smelter.

An assay analyzed silver content in a random sample from a batch of ore. That measure offered a benchmark from which to predict profit. As the price of silver changed, the proportion of the metal that would cover smelting and transportation costs also varied. When milling reduced shipping and smelting costs, assays offered a measure of quality before and after the process.

An assay functioned to keep everyone honest, much as analyses of comparable properties do in real estate today. A prospector who promoted the sale of a claim or lease depended on the analyses to document the value of their offerings. Conversely investors relied on assays to raise shareholders’ expectations.

Mine owners used assays to estimate how much a smelter should pay for processed product. Assays guided the twists and turns of ore exploration. And mill operators valued assays when they fine tuned innovations such as chemical processes to separate lead, zinc and silver.

Lloyd Ward performed assays for the Midnight Mine from within the building that became Elli of Aspen on Mill Street. The Midnight increased production to meet demand for strategic minerals during World War II and needed three expensive, time-sensitive assays each week.

Ward died in 1944, and the mine had to send its samples to Denver. But a stopgap measure soon developed. Facing shortages of vital workers nationwide, the war department created crash-course programs to train replacements, assayers included. Fred Willoughby, my father, and Frances Herron, his sister, enrolled in the course. Frances specialized in wet analysis. My father learned dry analysis, which required that he melt materials.

Traditionally, mine operators delivered samples to the assayer at the end of the day and expected results the next morning. Father worked long days underground and then performed assays, which added three to four hours’ work, three nights a week. The Midnight rented a space for him on Hyman Street near where he lived in the Cowenhoven Building. During the war, the mine produced 2.5 million pounds of lead and 1 million pounds of zinc. After the war, Father continued the assay work and processed his last sample in 1951.

I benefited from that work after the assaying shut down because a shed behind our home stored the equipment. My childhood playground offered all the unused assay cups and crucibles I could want, plus many fired with colorful residue on the bottoms. With a leftover scale, I could balance rock on one tray against tiny weights I would place in the other. The precise scale tipped with a greater degree of accuracy than a young boy’s fine muscle skills could handle.

I wish my father had trained me to do assays. I might have learned more about minerals doing assays than I did from geology textbooks.

Tim Willoughby’s family story parallels Aspen’s. He began sharing folklore while teaching Aspen Country Day School and Colorado Mountain College. Now a tourist in his native town, he views it with historical perspective. Reach him at redmtn2@comcast.net.

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