Kyanite Mining at Willis Mountain, Virginia
This weekend, I spent three days on an extended field trip down to southwestern Virginia with NOVA adjunct geology instructor Chris Khourey and four of my Honors students. We left Annandale on Friday morning, and made our first stop at Willis Mountain, Virginia, site of one of the most productive kyanite mines in the world.
Here's a Google Map of the mountain:
The Kyanite Mining Corporation was very gracious in hosting us. I'd particularly like to thank Mike Morris, who took two hours out of his day to show us the site and the mining operation.
Why mine kyanite? It's used as a refractory mineral: that is, one that won't melt under high temperatures. A lot of their kyanite is heated in kilns to produce a second mineral, mullite. The mullite is even more stable than kyanite in high temperature refractory situations. (It won't melt until it hits over 1800 degrees C!) Additionally, they cleverly saw up big blocks into dimensional stone for countertops and the like.
The kyanite mined at Willis Mountain is in a quartzite which also includes a fair amount of pyrite and hematite. We heard about the different procedures used to extract the non-kyanite minerals so that their end product is relatively pure and of constant quality.
Here's Mike showing the overall anticlinal shape of the deposit:
It's a plunging anticline, as you can probably make out from the Google Map terrain view up top.
Some of the dimensional stone, which I think is pretty spectacular:
Close up of the kyanite (light blue, on left) in the dimensional stone.
Nearby Baker Mountain also hosts kyanite deposits, which show a deeper blue color (Mike wasn't sure why, but suggested that chromium may be responsible):
Inside a huge storage building where the mullite (white powder at our feet) is stored:
Atop Willis Mountain itself, showing the weathered kyanite quartzite exposed there:
Honors students ask questions of Mike:
Mike and Chris standing near some fresh boulders of kyanite quartzite:
It wasn't all metamorphism and mining... I also noticed these nice raindrop impressions in a drying mud puddle:
After lunch atop the mountain, we hopped back in the van and hightailed it for southwestern Virginia, on our way to the Virginia Geological Field Conference. More on that tomorrow.
Thanks again to Mike and the good folks at the Kyanite Mining Corporation for hosting our visit!
Here's a Google Map of the mountain:
The Kyanite Mining Corporation was very gracious in hosting us. I'd particularly like to thank Mike Morris, who took two hours out of his day to show us the site and the mining operation.
Why mine kyanite? It's used as a refractory mineral: that is, one that won't melt under high temperatures. A lot of their kyanite is heated in kilns to produce a second mineral, mullite. The mullite is even more stable than kyanite in high temperature refractory situations. (It won't melt until it hits over 1800 degrees C!) Additionally, they cleverly saw up big blocks into dimensional stone for countertops and the like.
The kyanite mined at Willis Mountain is in a quartzite which also includes a fair amount of pyrite and hematite. We heard about the different procedures used to extract the non-kyanite minerals so that their end product is relatively pure and of constant quality.
Here's Mike showing the overall anticlinal shape of the deposit:
It's a plunging anticline, as you can probably make out from the Google Map terrain view up top.
Some of the dimensional stone, which I think is pretty spectacular:
Close up of the kyanite (light blue, on left) in the dimensional stone.
Nearby Baker Mountain also hosts kyanite deposits, which show a deeper blue color (Mike wasn't sure why, but suggested that chromium may be responsible):
Inside a huge storage building where the mullite (white powder at our feet) is stored:
Atop Willis Mountain itself, showing the weathered kyanite quartzite exposed there:
Honors students ask questions of Mike:
Mike and Chris standing near some fresh boulders of kyanite quartzite:
It wasn't all metamorphism and mining... I also noticed these nice raindrop impressions in a drying mud puddle:
After lunch atop the mountain, we hopped back in the van and hightailed it for southwestern Virginia, on our way to the Virginia Geological Field Conference. More on that tomorrow.
Thanks again to Mike and the good folks at the Kyanite Mining Corporation for hosting our visit!
Labels: conferences, economics, field trips, metamorphism, minerals, nova, piedmont, teaching, virginia
3 Comments:
I didn't know you could get kyanite dimension stone - I'll have to figure out some reason to order some!
Willis Mountain - one of my first mine tours, a very neat place. Thanks for the great report!
Yes, I want kyanite built into my house, too!
(Also, as I was reading about kyanite being stable at high temperatures, I thought "hey, shouldn't it transform to sillimanite or andalusite? It's the low-temperature polymorph! But then you mentioned mullite, and I remembered that experimental petrology on the aluminosilicates is notoriously slow and difficult. Hooray for metastability, then.)
I find the foresight w/r/t environmental issues that the owners and operators of the mine have had over the years to be extremely impressive.
Very fun mine to tour.
Post a Comment
<< Home