Modern life simply wouldn’t be possible without materials from mines.
Thousands of tons of gravel support the runways at SeaTac Airport. Large riprap rocks protect the new park at Point Defiance Park from being washed away. Sand helps support athletes during games at CenturyLink Field.
All of these materials came from a mine, and they all happen to come from Washington Rock Quarries.
Where do Washington Rock’s materials come from?
Our rock, sand, and soil products come from two locations: a quarry (Kapowsin Quarry) and a sand and gravel pit (King Creek Pit). Both locations are open-pit mines, which means that instead of tunneling underground, miners extract materials from the surface.
What is a quarry?
When you think of a quarry, you might imagine slick cliff faces or large blocks of stone.
An excavator at Kapowsin Quarry loads rock into a crushing machine.
Kapowsin Quarry is a basalt quarry. Unlike a granite or marble quarry, we don’t cut rock into perfectly rectangular blocks. Instead, we break up rock deposits with dynamite. The rock is blown into large pieces, which are sorted by size. Most of the rock is broken down even more and crushed into pieces of many different sizes.
The size of the rock determines how it will be used. For example, oversized boulders can be used to create seawalls or landscape features. Quarter-sized rocks can be used for gravel, while fist-sized rocks are used to stabilize railroad tracks.
What is a sand and gravel pit?
King Creek Pit doesn’t have a deposit of solid rock but is a mix of soil, round stone, and sand. Tens of thousands of years ago, a glacier probably passed through the area where the pit is now and dragged along with it rocks of many sizes and colors. The stones can be as small as a pea or as big as a car.
Banks of virgin earth at King Creek Pit tower over an SUV.We don’t use dynamite at King Creek Pit to mine materials. Instead, excavators dig up the soft soil and deposit it in a machine that separates the rock from the soil. Some areas of the pit have sandy layers that are scraped from the surface and used to make sand.
Together, Kapowsin Quarry and King Creek Pit supply over 1 million tons of material to projects throughout Washington State and across the U.S. every year. The next time you drive on a road or feel the gravel of a hiking trail under your boots, remember that it was made possible by a mine.