Friday, December 17, 2010

Maury Island and Mining

North end of run ways at Seattle Tacoma Airport

While getting ready for takeoff I took this picture of the end of the run way at Seattle-Tacoma Airport. Big airports cover lots of ground and alter the landscape significantly. In the case of this airport lots of fill was required to extend the run ways over a low area at the north end of the runways. Bridges were constructed to support landing lights beyond the ends of the runway. But the changes to the landscape extend beyond the airport. All that fill has to come from somewhere and so the changes to the landscape take place elsewhere as well.

East shore of Maury Island

One source of sand and gravel is visible right after take off. The west shore of Maury Island has several mines. The mining takes place in glacial advance outwash, deposits of sand and gravel associated with melt water from the advancing glacial ice that pushed down into Puget Sound from the north. These deposits are particularly thick on Muary Island. Cal-Portland a Japanese owned concrete producer planned a major mine expansion on the island about ten years ago. The permitting process has taken a very long time primarily because the mine proposed using water access to ship via barge the mined aggregate. Without the ability to ship by water the value of the deposit is limited due to the low demand on Maury Island and Vashon Island (the two islands are actually attached via a narrow neck of land).

There are a variety of permits that are needed for any gravel mine, but water access and the construction of a pier involve more permitting than the mine itself. A variety of groups opposed the pier construction, but the mine obtained most of the permits until 2009 when a Federal Court judge ruled that the Army Corps of Engineers needed to do a more in depth analysis of the proposed pier and how noise and shading from construction and operation might harm orcas and chinook salmon, both of which are listed as endangered species. David Mann who recently argued a Freedom of Information case before the U.S. Supreme Court regarding another Washington Island was the attorney for groups appealing the Army Corps initial permit (see HERE)

After that decision the mining company became more receptive to selling the land and leaving the project. In April 2010 the Washington State Legislature approved $14.5 million for purchasing the land. King County Council approved $19.1 million dollars in November 2010 as well as a non monetary agreement worth $2.4 million regarding another mine site that is owned by the county but leased to the mining company. There is a commitment of $2 million by non profit groups to partially offset the County's purchase. 

The State money comes from a settlement fund paid to the state by another mining company, ASARCO. ASRCO operated a smelter in Tacoma for many years and one legacy from that smelter is an area wide contamination of lead and arsenic from air borne deposition. One of the places most impacted by the smelter is the Maury Island and Vashon Island area, so there is a link between using the money at the location to offset the damages caused by the smelter. The County money is from a Conservation Tax, a property tax for purchasing properties for public open space. Many Washington Counties have such a fund. In King County the fund collection is bolstered by the high value of land in the most populous county in the state.

From a gravel mining perspective, this means that the value of other deposits that could serve the area or have an easier time accessing water will increase in value and demand. Gravel mining already takes place with water access south of Tacoma and a pit in Jefferson County near Hood Canal has proposed a conveyor system to load barges. There is a small rock quarry on Lummi Island in Whatcom County with water access and several mines in the straits between Vancouver Island and main land British Columbia.  But other market factors also play a role. Some projects may not be constructed if the prce of aggragate gets too high or projects may be redesigned to use less aggregate or different materials.

At this point it looks like a new park with water access is in the works for the east shore of Maury Island. The geologic map that covers Maury Island (Booth, 1991) notes that the area of homes that can be seen on the photo above is modified land associated with mining. Post mining development is not uncommon. Shopping centers have been built in the old mines in Monroe and a residential development and championship golf course have been in development south of Tacoma in an area mined out.       

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