Reserve Silica & Landsburg Mine Site Cleanup

On Monday, March 4, the Area Council held its monthly meeting received an update on the cleanup status, under the State’s Model Toxics Control Act (MTCA), for both the Landsburg and Re- serve Silica mine sites. Guest speakers, respectively, were: (1) State Department of Ecology’s (DOE’s) Jerome Cruz and Brad Petrovich and (2) DOE’s Tim O’Connor and Alan Noell.

Landsburg Mine Site MTCA Cleanup

The site is a former underground coal mine located ~1.5 mi northwest of Ravensdale (south of Summit-Landsburg Rd, north of Kent-Kangley Rd). The Cedar River is ~500 ft north of the site. The former mine site occupies property currently owned by Palmer Coking Coal and formerly by Plum Creek. During the late 1960s to late 1970s industrial wastes (in ~4,500 drums) were disposed in the trench (20-60 ft deep; ~100 ft wide) that formed above the former coal seam. DOE has found no groundwater contamination in a variety of test wells dug over several years (DOE tests for ~120 chemicals). This site is now being monitored and subject to cleanup under the State’s MTCA.

A Consent Decree for cleanup under the MTCA was agreed to with Potentially Liable Parties in November 2017. Since then engineering design is complete; cleanup construction is nearly done in- cluding clearing and grubbing to access key part of the site, sentinel wells have been installed; and groundwater is being monitored quarterly.

DOE is working to ensure there is no detectable contamination of nearby private wells to the northwest and the Cedar River. Consequently, groundwater has been monitored at the site using 10 monitoring wells set at various depths and locations. The groundwater was analyzed for around 220 contaminants in order to detect any potential contamination coming from the waste area. Low levels of 1,4-Dioxane were found at several monitoring wells on the site that exceed allowable levels under MTCA standards. Three additional monitoring wells were installed to further investigate the 1,4-Diox- ane near the north portal of the trench. Chemical validation has yet to be completed.

1,4-Dioxane is a man-made industrial chemical that is mixable in water. It is used as a stabilizer for chlorinated solvents and is a byproduct in many products. It is a likely human carcinogen and low- level exposure over a lifetime can increase the risk of cancer. Arsenic also has been detected in one deep interior well.

Long-term groundwater monitoring will be conducted. The Final Cleanup Plan calls for putting in clean fill and capping the trench with a clay-like material. Alongside the cap will be diversion ditches to capture excess surface water draining off the cap. Contingency plans for any contaminated water include pumping out, containing, treating, and discharging it.

More information can be found on the Area Council’s web site:, which has links to the DOE presentation materials and all related information.

Reserve Silica and previous owners and operators used the site (generally located at 28130 Black Diamond–Ravensdale Rd near Ravensdale) for coal through 1956 and sandstone mining until 2007. As part of site reclamation, the mine pits are being backfilled with materials from construction sites. Once the pits were mined out, reclamation was required starting in 1979. Monitoring on site started in 1984.

Through the 1980’s a corrosive material called Cement Kiln Dust (CKD)—a fine-grained, solid, highly alkaline waste removed from kiln exhaust gas by air pollution control devices during the pro- duction of cement—was disposed of in two of the open mine pits: Lower Disposal Area – a former open pit sand mine reclaimed between 1979 and 1982 — and Dale Strip Pit – a former open-pit coal mine reclaimed in the 1980s. Both pits were filled and closed under solid waste permits issued by Public Health Seattle King County (Public Health), which also issued a Post-Closure Maintenance Permit. Reserve Silica is now filling the final surface mine area with inert waste, under permits issued by Public Health and DOE.

One of the concerns with CKD is that when it comes in contact with water, it releases toxic metals. Groundwater moving through the CKD in the Lower Disposal Area pit has seeped to the surface. Groundwater and surface water contaminants include high pH (corrosive) water and toxic metals— including arsenic and lead. Contamination from this site has the potential to affect plants, wildlife, sur- face water, and groundwater on and near the property.

Holcim, one of the potentially liable parties associated with the deposit of CKD on site, has put in place a leachate treatment system, which lowers the pH and attempts to filter out metals. Treated wa- ter then is sent to infiltration ponds, which seep down into the ground.

An Agreed Order under the State’s Model Toxics Control Act (MTCA) still is in negotiation with Po- tentially Liable Parties). The Draft Cleanup Plan is expected in 2023.

More information can be found on the Area Council’s web site:, which has links to the DOE presentation materials and all related information.


The Puget Sound Regional Council (PSRC)—the 4-county Regional Planning Organization—is developing VISION 2050, an update to VISION 2040, released in 2008, and currently the region’s growth management, economic, and transportation strategy. It was designed to meet the needs of the 5 million people expected to be living in the region in 2040. It is an integrated, long-range vision for the future that lays out a strategy for maintaining a healthy region — promoting the well-being of peo- ple and communities, economic vitality, and a healthy environment.

VISION 2050 is being developed as forecasts show the region needs to plan for another 1.8 mil- lion more people and 1.2 million new jobs by 2050. The population is expected to reach over 5.8 mil- lion in 2050. VISION 2050 is intended to guide growth to support thriving communities, a strong economy and a healthy environment.

PSRC released a draft Supplemental Environmental Impact Statement (SEIS) for VISION 2050 on February 28. It evaluates the environmental effects of three regional growth alternatives: Stay the Course (No Action Alternative), Transit-Focused Growth, and Reset Urban Growth.

The GMVUAC is coordinating a joint response with its “sister” Unincorporated Area Councils/Un- incorporated Area Associations throughout the King County. Public comments are due to PSRC on April 29. More information can be found at:

Upcoming Monthly Meetings (All monthly meetings are from 7 – 9:30 PM and held at the Fire Sta- tion located at the SE corner of SE 231st St & SR-169 intersection across from the Police Precinct. All members of the Public are welcome. Each meeting begins with an open Public Comment period.)

Department of Local Services: Monday, April 1. A “Special Event.” Our Guest Speaker with be John Taylor, Director of the King County’s new Department of Local Services (DLS) which is comprised of Permitting (formerly Dept. of Permitting & Environmental Review—DPER) and Roads (formerly part of the King County Dept. of Transportation—KCDOT).

Water Restoration & Enhancement (WR&E) Committees: Monday, May 6. The progress of the WA Department of Ecology (DOE)-established WR&E Committees will be discussed with DOE repre- sentatives and the Center for Environmental Law & Policy (CELP), which serves on the WRIA-8 (Cedar River Watershed) WR&E Committee.

King County Comprehensive Plan (KCCP) Update: Monday, June 3. KCCP Manager, Ivan Miller, will discuss the 2020 KCCP Mid-Point 4-yr Update and the Public Review Draft to be released for 30-day comment in July.

Your Area Council serves as an all-volunteer, locally elected advisory body to King County on be- half of all rural unincorporated area residents living in the Tahoma School District. Please see the Area Council’s web site: The Area Council has two open positions. If a resident has an interest, he or she should attend one of our meetings and express such interest for consideration by the Area Council.