Frequently Asked Questions

What is the purpose of the mine expansion?

● The purpose of the expansion is to extend the life of the current mining operation and to incorporate an additional 56 acres to the mine.

Where has material from the mine been used for local projects?

● 382k tons of material extracted from the Granite Falls operation has been used locally in recent projects including:

• • Resurfacing Mountain Loop Highway
  • SR 9 South Lake Stevens Road intersection improvements
  • Lake Stevens Costco construction
  • Additional projects for Amazon, Sound Transit, and residential developments in Snohomish County

What are the potential impacts to the community from the mining operation and what is being done to help mitigate each of these impacts?

• Noise and Vibration from Blasting: The operation requires the continuation of drilling and blasting with explosives to access the rock at the site. That creates the potential for both noise and vibration impacts. Heidelberg Materials has proven techniques to avoid/mitigate impacts. These include (but aren’t limited to): exact calculations for spacing of drill holes and blasting targets to minimize the noise to the greatest extent possible; using seismographs to monitor vibration levels. Heidelberg Materials has retained BRC Acoustics to develop a noise study and conduct noise monitoring at the site. Heidelberg Materials will continue to abide by the restrictions in the current conditional use permit that specify when blasting can occur.
• Groundwater Impacts: Heidelberg Materials will continue to conduct operations in a manner that avoids or minimizes potential impacts to the local aquifer. There is an existing groundwater monitoring program for the site which will be updated to account for the expanded mine footprint.
• Aesthetic Impacts: Currently, only the entrance is visible from the road, and this will not change with the expansion.
• Truck Traffic: Heidelberg Materials does not anticipate any increase to truck trips because of the expansion. The proposed expansion will provide access to additional reserves of aggregates but will not change the types or quantity of materials mined each year.
• Dust: Transport of the material from the mining area to the processing area has the potential to create dust which will be mitigated by best available technologies (i.e., water trucks for roadways).
• Road Debris: All Heidelberg Materials trucks are required to cover their loads as part of company policy. Many of the trucks that come to the site are customers of Heidelberg Materials, and do not have to abide by this policy. Though it is strongly encouraged that ALL trucks cover their loads, it is not required by law as long as the vehicle bed maintains six inches of freeboard (See RCW 46.61.655). These secure load requirements are enforced by Washington State Patrol.

How often does blasting occur at the mine?

• Blasting typically occurs between 6 and 12 times per year. We have an email list that receives notifications when Heidelberg Materials knows they will be blasting the site. Please join the list by clicking here.

What does your groundwater monitoring program entail?

• The well monitoring network consists of 9 wells spread out across the current site. The wells are monitored for arsenic, pH, specific conductance, temperature, and static water level. Three of the wells are monitored quarterly, and six are monitored annually. There are two wells that are monitored for water level only. Annual groundwater monitoring reports are provided to Snohomish County.

What is the expected length of time this mine will be in operation?

• • The permitting effort is for a 25-year mine life, although it is expected actual reserves will last longer than 25 years. If there are remaining reserves, Heidelberg Materials will likely go through this process again in 25 years to submit applications for new permits.