Cornish Buddles Unearthed at a Michigan Copper Mine

The copper mines of Michigan's Keweenaw Peninsula were America's most important source of copper for most of the 19th century. Copper in this region exists in its native metallic state, unalloyed with other minerals. Large-scale development of the district began in the 1840s, when a geologist's report on the prospects of the area helped spawn a mineral rush. Numerous companies bought tracts of land and sent crews to begin exploratory work. Cornish mining technology came to the region with immigrant miners and was a key factor in the district's development. The organization of underground work and the stamping and washing practices all drew on Cornish precedents. A small number of mines, the Cliff, the Minesota [sic], and later the Quincy, and the Calumet & Hecla, were very productive and profitable. Most of the early ventures were not so successful and expended the investors money without returning a profit.

Michigan Technological University students and faculty, Ottawa National Forest archaeologists, and volunteers have been researching one of the early failures, the Ohio Trap Rock mine, for several years. Mining began at the site in 1847, and by 1858 the original company had expended its capital and closed down. Other companies continued to work the same copper veins, but appear not to have used Ohio Trap Rock's surface works. Over the last four years we have mapped the site, surface collected approximately 10 acres (primarily the domestic area of the site), test excavated three structures, and studied historic information about the site. The most extensive excavations have taken place at the company's stamp mill, one of 35 surface buildings the company constructed . At the stamp mill mine rock was crushed and washed to liberate small grains of copper. The mill at Ohio Trap Rock was apparently built in 1852, and was probably out of use by 1858. The mill had 24 stamp heads run off a 40 horsepower steam engine. Over the past three seasons we excavated 19 test units covering 56 m2 of the structure. The combination of archaeological and historical research has given us a very good idea about the construction, layout, and organization of this early mill.

The 1994 and 1995 excavations centered on portions of the washing and laundering system where the copper was concentrated after the rock was crushed. Most of the test units had very similar stratigraphy. The first 5-10 cm were a dark brown mat of roots and decaying twigs, leaves, pine needles, and other organic matter. Beneath this organic layer was sand, the byproduct of the stamping process of the mill. The sand was olive green, and ranged in consistency from silty-sand to very coarse sand. The residual copper in the stamp sand sediments acted as a biocide and contributed to excellent organic preservation. Wood, leather, and other organic materials in the sand were well preserved, and the buried wooden components of the structure were in virtually perfect condition.

The sill of the washing house, sections of working floor, drainage and supply trenches, a classifying or jigging area, and sections of two circular buddles were all found in the excavations. The mill burned, and there were many charred wooden pieces of the structure that had fallen down and been buried. The most striking example was a portion of a wooden door . This was constructed of several layers of planks held together with clenched nails, and still had a fragment of a hinge attached. Only the bottom of the door remained, as the upper portion had burned away. This door remnant was lying on top of a preserved section of wooden floor, which also yielded several intact barrel bottoms.

Nails, bolts, washers, spikes, window glass, pieces of lumber, and other architectural artifacts were scattered throughout the stamp sand deposits. Two major artifact concentrations were also excavated. One was a mix of fill, trash, and destruction rubble that contained several copper alloy brackets, barrel parts, textiles, sections of metal pipe, and a host of other artifacts. The second concentration was in the fill of one of the drainage trenches. This contained many well preserved organic artifacts including textile fragments, several pieces of leather boots or leather leggings, and several sections of wooden trough. It also contained half of a metal-bound wooden crown gear. The gear was originally about a meter in diameter with projecting wooden pegs around the edge to engage another gear. This might have been part of the drive mechanism to power the sweeps on one of the buddles.

The remains of two circular convex wooden buddles are the most interesting discovery. Each of these had a vertical metal shaft in the center, surrounded by vertical planking approximately 55 cm out from bearing. Outside the vertical planking was a horizontal wooden floor that sloped down slightly away from the center. The floor was made of wood planks radiated out from the center of the buddle. These were tongue-and-grooved together, and cut with a taper so that they widened towards the edge of the buddle. The outside edge of floor was not truly round, but polygonal. Vertical planking about 25 cm high was attached to the exterior edge. Floor butted up against the vertical planking on one side, and in another area a wood-lined trench was next to the edge of the buddle. The trench seems to have been designed to help drain water and fine sand out of the buddle. We excavated from the center of one buddle across to the outside edge, and it proved to be about 9 meters in diameter .

In 1851 the Ohio Trap Rock company fired the English mine captain who was their on-site agent, and hired an experienced Cornish miner, Captain Joseph Buzzo, in his place. Buzzo tripled the workforce to more than 100 workers and directed the construction of additional surface facilities. It is likely that Buzzo and Cornish miners he hired built the stamp and washing house. The wooden buddles at this site represent a serious investment of time and effort, yet they were only in use for a few years before the company shut down. Circular buddles are a distinctly Cornish style technology, and were the leading edge of ore dressing technology in the 1850s. This technology was not well known in North America. The presence of these buddles at the Ohio Trap Rock mine site shows the early transfer of Cornish copper processing techniques to Michigan's Keweenaw Peninsula.