The Comstock Foundation for History and Culture purchased the historic Donovan Mill in Silver City, Nevada, USA. Originally called the Jackson Mill, this important site in Silver City reflects a fully integrated production facility, preserving evidence of one of the earliest experiments in the cyanide processing of gold and silver ore in the USA.

“The Donovan Mill represents some of the more important and lasting technological innovations that made the name Comstock a legend in the mining industry,” said Corrado De Gasperis, chairman for the Comstock Foundation. “The buildings were at risk of being dismantled and lost. Our whole board felt it was critical to take this step in an effort to preserve this significant historic and cultural resource.”

De Gasperis is also the CEO of Comstock Mining Inc., which has dedicated a 1% royalty of its Storey County operation’s net smelter return to the Comstock Foundation for the advancement of historic preservation and other aspects of cultural development within the historic district.

Much of the Donovan Mill — including 10 of its 30 stamps designed to crush ore into a fine powder — dates to 1890 when the Comstock Mining District was enduring a slump. At the turn of the century, Dr. J. Warne Phillips at the University of Nevada in Reno formed a partnership with the mill operator to experiment with the newly invented approach of using cyanide to precipitate gold and silver from ore. The process proved a success, and in 1904, Phillips secured full ownership of the mill.

The success of the efforts of Phillips with the mill encouraged others to employ the new cyanide process, which promised to renew productivity of mining on the Comstock and elsewhere: the innovative approach for extracting precious metal meant that lower grades of ore could become profitable, allowing for more productive excavations of ore within mining districts that had ceased operations.

The timing of the experimentation with cyanide coincided with the 1903 discovery of a rich ore body on the north end of Virginia City. The combination of a more efficient approach to milling and the discovery of new ore bodies renewed the vigor of the Comstock, employing miners and once again infusing wealth into the region’s economy.

As Phillips was demonstrating the success of his approach, R. A. Trimble constructed another cyanide mill next to the Jackson Mill in 1900. Known as the Pollard and Trimble Mill, this facility proved to be extremely profitable. In the first decade of the 20th century, William Donovan Sr. purchased that business, and then acquired the neighboring mill operated by Phillips, consolidating both operations under his sole management. Donovan managed the facility for the next 30 years, reaching a capacity of processing 100 tons of ore daily.

In the 1920s, William Donovan Jr. began to assist with the management of the mill, which ceased operation in 1959. Since that time, the historic site has continued to dominate the southern approach to Silver City. “

Experts in the history of mining technology have long recognized the national significance of this site,” said Ron James, executive director of the Comstock Foundation. “I am pleased that our non-profit organization can assist in the preservation of this important resource, and we look to our fellow Nevadans for support as we attempt to restore the site.”
The Historical American Engineering Record — or HAER as it is commonly known — documented the Donovan Mill in the early 1980s. The project was an undertaking of the National Park Service.