Project helps find abandoned Santiam Canyon mines

Santiam Canyon mining operations of yore coupled with seasonally dry trends of recent years combine to create potential safety hazards for foresters and public safety crews such as firefighters.

Fortunately, new marking and mapping of abandoned mine sites in the North Santiam Mining District has emerged following a four-year project using lidar (light detection and ranging). The project is a welcome one for those who work in the Willamette National Forest, within which the mining district falls.

Oregon Department of Geology and Mineral Industries (DOGAMI) Earth Science Information Officer Ali Ryan said the U.S. Forest Service initiated the project to inventory mine sites and features, primarily with safety issues in mind.

"USFS was particularly interested in knowing where mine openings had been closed with foam, because it accelerates fires," Ryan said.

One historically-related bonus that arose through the project was an appreciation of the tenacity and perseverance of those who once mined the canyon.

"The mountains are rugged, with steep, densely forested terrain," said Clark Niewendorp, industrial minerals geologist with DOGAMI. "Prospectors had to be extremely motivated to get in there."

A March, 1985, report issued through the U.S. Department of Agriculture titled "Little North Santiam Mining District Cultural Resource Inventory Report" indicates that initial mining in the region dates back to 1860 with claims filed in the Marion County Clerk's Office.

The report preparer, archeologist James B. Cox Jr., noted:

"Most of the available accounts speak of the tremendous potential of the area. This potential has never been realized. Investment in mineral development in this area runs into the millions of dollars, but reported production between 1880 and 1947 totalled $25,000 (Anon., 1951)."

Ryan said some mining resumed in later years; in 1977 the Shiny Rock Mining Corporation reopened the Ruth Mine and development of several other claims. Mining in the district ceased in 1992 with the closure of the Ruth Mine.

The decades since have seen the hundreds of former mine features overtaken by the region's heavy vegetation. DOGAMI's use of lidar to uncover these mine features has paid huge dividends: the project's maps reveal 226 abandoned mine features in the district, including mine entrances, exploration pits, and waste rock areas; previous mapping showed only 58 abandoned mine features.

"We can now see an incredibly detailed image of the earth's surface," Niewendorp said. "Lidar imagery has real value for inventorying abandoned mine land, because it can show mine openings that weren't well documented, or that were even completely unknown."

That's good news for foresters and firefighters.

"Lidar aids in the inventory and closure of abandoned mine features with the aim to protect public safety," said Ruth Seegar, a U.S. Forest Service minerals geologist for western and central Oregon and western Washington. "Lidar is an effective tool in advance of a ground survey because it increases the efficiency and labor of a time-consuming abandoned mine survey."

Ryan said the four-year project came together incrementally with lidar technology providing the foundation.

"Geologists first identified likely abandoned mine features with lidar, then field (workers) verified those features," she said. "Finally we created the inventory maps."

The safety elements go beyond just forestry personnel.

"The area is widely used for recreation," Ryan added. "Oregon's had a few dry years; the combination of people and dry conditions can lead to fire. Knowing where mine features are helps keep firefighters safe should a fire happen."

jmuch@StatesmanJournal.com or (503) 769-6338, cell (503) 508-8157 or follow at twitter.com/justinmuch