LiDAR shows where old mines are collapsing in the Appalachian Mountains

Historic iron mining in the Virginia Valley and Ridge produced plenty of ore and also cause large-scale slope movements. Most of these shifting mines are located in Botetourt and Alleghany Counties. Highwall cuts that exposed the ore led to mountainsides shifting enough to produce scarps and cracks visible with LiDAR imagery. One hilltop actually sank about 8 feet as the surrounding slopes bulged outward due to mine activities. The forest has reclaimed the mine areas now, but the fascinating geologic impacts remain as a reminder just how unstable some landscapes can be.

[@cowboygeologist7772]

Great presentation. There's an area in a town a few miles from me like this. They removed the toe of the mountain from mining. There's a huge slump area and crack on the mountain. I told my friend, the Sheriff, if that slides on down, Virginia City could have a chain reaction from all the abandoned silver mines under the town collapsing. At minimum, it would make a noise that would even scare off the ghosts - lol.

[@TheGeoModels]

I have wondered how prevalent big but subtle movements like this are. I guess you can actually see them in a drier place without trees everywhere! Most Appalachian slopes that experience large but deep, gradual movement appear to be susceptible to just that--large and slow movement. Plenty of huge slope failures have a stream eroding their toe, and they just creep along. I'm not sure if there is enough potential energy in the landscape to make more rapid large, deep failures, but nobody would want to find out, either. I was recently told about a bridge piling with anchors going 80 ft deep that was moving peacefully along on top of a huge landslide. The slide was apparently 115 ft deep.

[@cowboygeologist7772]

@TheGeoModels not sure if this will work on here. If it does, it's on Google maps, horseshoe shaped above the open pit mine. Very deep and obvious from the ground. ⁦39°18'10"N⁩ ⁦119°39'25"W⁩

[@moendopi5430]

Very interesting! I did a seismic/geophysics job out in Iron Gate a few years back. Now I know why it got its name.

[@TheGeoModels]

What yall looking for out there (if you can divulge)?

[@moendopi5430]

@@TheGeoModels Ah, well, there was an old gas pipeline that was put in back in the 40s(?). It was gonna get replaced so we were doing a depth to bedrock study to see where competent bedrock started. Basically they needed to know where they could blast or just use a dozer. Some areas we did them in, I don't know how you would get a dozer back there. Also, carrying a car battery up or down those slopes was not fun. Also, those adits sound dangerous. I don't know if the Virginia Survey has closed them off, but a buddy of mine and I explored some old small mines around Dadeville, Alabama which were not marked or closed off, but abandoned. If you fell down into one of those, you're not coming back out. I have a video of one where we dropped a GoPro down in one. If you look closely towards the end, you can see deer bones at the bottom. Don't wander the woods at night.

[@j.douglassizemore792]

Being born and raised in the mountains of Eastern Kentucky near Black Mountain and having worked in the coal mines of Appalachia including Kentucky and Alabama, I did not know about the geology of those mountains south and east of the coal field. Thanks for educating me and presenting such a nice video.

[@valoriel4464]

Great presentation. Thx. ✌🏻 enjoyed hearing a speaker that doesn't add in uhh, you know, etc. Well done Sir.

[@TheGeoModels]

I do my best! Glad you enjoyed it!

[@michaelmartin4816]

Very cool! My great grandparents lived in Covington & I spent a lot of my Summer's up there while growing up in the 80's & early 90's. Would swim in the creek at Humpback Bridge which was actually owned by my family way back when. My grandfather's parents are buried in Low Moor. I love those mountains! Very interesting to see them in a different perspective!

[@TheGeoModels]

They are something else. When you look at them with this sort of digital topography there are lots of "humpback" looking features. Big Hill on 220 is particularly interesting. Low Moor is really cool from the standpoint of landscape evolution--the river has some old terraces and meander cut-offs way up in town. You could find "river jack" cobbles way up on the hills today and wonder how on earth they got up there.

[@daver00lzd00d]

this is an amazing video!

[@MorganBrown]

OMG, the LIDAR is incredible. You guys don't even need to walk the transects anymore. 😂

[@TheGeoModels]

I guess it's nice to ground-truth features, but the lidar is def a game changer. Lots of structural geology work in Appalachia is legitimately better done with lidar, at least from a qualitative standpoint in heavily forested areas

[@fredwood1490]

I grew up in central West Virginia where a great deal of strip mining took place in the 1930s and 40s. I used to roam those hills above the strip mines and found many such slip faults, where the top of the mountain had become unstable. This was in the 1960s so it must be much worse by now. There are few people living directly near the strip mines but those who are, in Brooklyn and other such places, may be in great danger. Since the underground mines have closed, in the late 20th century, water has stopped being pumped from the mines so many springs have returned, weakening the rock structure even more. Nothing can be done about the slippage but what can be done to warn the people way back in the Hollars?

[@cherylm2C6671]

Thank you for your presentation! There have been recent terrestrial landslides that have impacted thousands of people, but your presentation is showing creepy similarities to some of the larger historic landslips. Can this be called geochemical faulting? Thank you for your work!

[@JamesChubbyDamron]

Are these landslides/ mine collapses the cause of the frequent minor earthquakes in western Virginia and other states?

[@TheGeoModels]

No, those are from deeper down in the Earth where more stress can accumulate and then slip loose. Most are a few miles deep, though some are only a couple of miles. The slides in this video still aren't too big in the greater scheme of things, and they probably didn't move all at once...I'd actually be interested to know! Check out Rattlesnake Mountain in Washington State; it's a recent landslide sort of like the ones in the vid. It moved over a period of time--it was fast geologically, but was still a slow process. Eastern North America has some tectonic stress on it. It's not huge, but there's enough there to make the Earth's crust slip and budge now and then. The fact that the Appalachians have so many old geologic structures in them allows the crust places to slip.

[@jimlescault2139]

I live in clifton forge, is that LiDAR map available online ? I'll totally go check them out

[@TheGeoModels]

It is on The National Map Viewer hosted by the USGS. Just Google for it. When the viewer opens, you have to select the Hillshade layer from the drop down menu. The Layer drop down is like a little stack of plates or cards or whatever. Select hillshade, and you can see a lot. They don't have slope shade, so the northwest ridges are bright, but it's still awesome.

[@10rcoleman]

I’m from Grundy Va they have deep mined striped mine this place to death there are still a few mines left buch 1 is a huge shaft mine they put out about 10 million tons of coal a year or did I haven’t checked in a while.

[@10rcoleman]

I always wondered why it is called iron gate I’ve seen it the exit on 81

[@phillipdavis3316]

I appreciate your videos and dedication, but the inset of your narrating is not necessary for the videos. It is distracting.

[@TheGeoModels]

I'll keep it in mind!

[@davechristensen2493]

@@TheGeoModels I enjoy seeing you in your presentations and I like your sketches too.