 So my name is Annika Brown. I am with the Cluster Gallatin National Forest and I am the assistant on-scene coordinator For those of you not aware of that term on-scene coordinator basically means project manager So today I'm going to go over the background of the site Go over some problems caused by mining the contamination issues we have at the site Our design challenges for our reclamation Why we chose to do landform design for our reclamation design And then I'll show you some cool before and after photos of past work we've done And go over the vegetation monitoring results And then what future work we have out at the site and how we measure success at the site So The site Riley Pass is located in the far northwest corner of South Dakota It is 25 miles north of Buffalo and just west of Ludlow We have 12 bluffs at the site Kind of spread out in the North Cave Hills area Which you can see on that larger map there So the geology of the site The landscape looks a lot like this photo I have right here. It's a nice flat Even sandstone cliffs and bluffs out at the site and then some rolling hills The fort union formation It is where We got the lignite beds that were mined in the 60s So these are about 63 to 50 million years old and Yeah Mining first occurred at the site in the first prospecting occurred in the 1950s And then mining happened from the early 1960s to 1964 and what they did was it was Strip mining so they just pushed off the overburden on top of the bluff either to the bluff edge or over the bluff edge To get to the black lignite beds that they were after And then this was all done before Modern reclamation laws were around so when they stopped mining they just walked away from the site and Left it how it is So of course Resulting from mining we have contamination. So the contaminants at the site are arsenic molybdenum selenium uranium radium and thorium so we've done some risk assessment at the site and Determined that our cleanup goals are 30 pico curies per gram for radium 226 And 142 milligrams per kilogram of arsenic if we focus on those two contaminants We will also be addressing the other contaminants at the site at the same time And then of course in areas where there was mining we have distressed vegetation So here are some good examples of bare ground. That's just been sitting there since the 60s and nothing's been growing And then due to the The high silt and clay content in the soil out there and the arid region As well as the wind We have a lot of erosion especially sent especially in areas where we don't have vegetation anchoring The soil down and we get these Really deep gullies that just go down down down down down just so deep The some of them are so deep that we've even lost cows in them So we're trying to address that so I have a close-up on the left side and then a zoomed out picture on the right side Yeah, you can see this giant goalie right here And then here's a good overview You have the the mining overburden that was just pushed over right here That's just all the mucky and gross And then what we're trying to do is clean this up Put it back on top of the bluff so that we can expose these beautiful sandstone cliffs that you can see in the surrounding area And these are just super steep in some areas. They're one to one So really steep not not able to walk on them And then also because of the soil out there It's really prone to piping so it's really unstable. It's hard to get equipment on certain areas. It's just dangerous and then because we have A high sodium adsorption ratio. It's really hard to get plants to grow out there So our cleanup goals also include Our plan is to isolate the contaminated material Place this in on-site repositories We cover this material with clean material and then we anchor it with vegetation and stabilize the ground with vegetation but also with Landforms and we're using natural landform design, which I'll get into more detail a little bit later but basically natural landform design incorporates features of the surrounding landscape so we can match that landscape, but also that provides us a good example of what The land surface eroded to So we're trying to jumpstart the geomorphological processes and so it'll be more stable in the future We also have contamination issues out there. You can't see or smell evidence of high arsenic or radium concentrations Also, lab analysis for radium Is really expensive and it takes about 30 days turnaround time to get those results back So it's just not feasible to collect a bunch of soil samples to evaluate our How our cleanup is progressing while we have heavy equipment out there just sitting on site. It's really expensive So what we do is we use field screening techniques. We use a gamma meter which measures radioactivity But that's in different units than Our soil cleanup goal So therefore we need to We use field screening methods, but then we cross check it by collecting Samples that we'll send out to the lab and make sure that we're meeting our cleanup goals Also, there's no point source of contamination out there. And there's no real pattern of contamination So here I have On the left hand side is an aerial photo. You can see the areas where there's no vegetation And then on the right hand side The pink indicates Where the contaminated material is And you can see they're not totally the same although keep in mind the Image with the pink outline. We didn't collect samples On those slopes because it just wasn't safe to get equipment out there and collect samples So you have to incorporate that in as well We also need to provide Direction to the contractors of where where to clean up so We're also planning on just taking all of the mining over burden off the side, even if it's not Over our cleanup goals, but just picking that up and putting them back on top of the bluff And encapsulating it the higher concentrations are going deeper into the landforms So they're going to be buried deeper and isolated from human health and the environment Then of course, we have design challenges. So our design plan is to Bring the site back to what it looked like pre mining conditions. So that was pre 1954 We don't have a lot of data from 1954, but we do have a topo map that we've digitized so The our plan is we kind of do a two-step process So we excavate the contaminated material and then Place those in repositories on the site and then we resurvey that site and then design the landforms on top of those So we ensure that the hottest material we place deep in those um In those landforms deep in those repositories also We're trying to uncover that beautiful sandstone cap But the sandstone isn't Evident in all places. So we don't know what areas it's there and What areas it just happens to be missing because we can't it's just not feasible to sample Everything on the site we have to kind of make guesses Also, we have to estimate the thickness of mine waste It's not even on all areas of the site So we have to make assumptions of how deep we think it is but that's definitely an issue We deal with and contracting and telling contractors how much material we think they're going to have to move And then also our work season is from April to October So we have to make sure that everything is buttoned up and stabilized before winter comes. The reason we do that is because We the ground is frozen in the winter and we can't reach our compaction goals with frozen material So we just perform work between april and october and then we do our design Over the winter for the next season And then why we're doing landform design. So basically landform design is replicating the features of the natural landscape. So Our goal is at the end of this That you won't be able to tell what areas were reclaimed and what areas were just not mined. So we're looking at Well natural natural landform design emphasizes diverse surface topography it has multiple slope angles and aspects small drainage basins and Looking at natural stream morphology as well as differing vegetation patterns And here's a good example of the same area at Riley Pass with two different designs So on the left is traditional mine reclamation and you can see there's really smooth uniform slopes We only have Two drainage ditches. So these would be really strong and lined with riprap to make sure that they're stable and Then on the right is the natural landform design and you can see There's at least 11 Drainages and they're very sinuous And they're at a low angle And we don't have those uniform slopes. It really Models the land in the surrounding landscape. So what we do is we collect data from unmind undisturbed areas such as stream sinuosity Um slope aspect and angle and we put this into a program in autocad And that puts out a design and then of course once we have that design We have to massage it to make sure it's constructable it's Yeah, it's constructable if it's our equipment and then also in the areas where the The reclaimed area meets the undisturbed area We need to make sure that that's going to be smooth because that's where a lot of Failures happen is that meeting point between the reclaimed area and the Un undisturbed So challenges out there as I've said before it's very dry. It's very windy waters a scarce resource and when we we have to use water for dust suppression But also we can't use too much because The water makes the ground really slippery really sticky. I know you guys are all familiar with gumbo so we That that's a challenge. So we like to start our work in the spring when the ground is Very moist and we don't have to use as much water for dust suppression And then of course we had those really steep slopes that are extra slippery when they're wet So because we have these really complex slopes Um, we've been using gps controlled equipment instead of having Surveys on site. We'd have to have surveyors on site Full-time or if we had to call them out for to survey an area that hadn't been done yet They're over 150 miles away. So it would be really expensive just to have Operators sitting around waiting to figure out what work they were going to be doing. So we used gps controlled equipment which Helps make the process a lot faster. So basically we input the design into the computers in the cabs and then the operators know How and or how deep and where they need to excavate or where they need to fill This is a map showing our 12 bluffs. Um, the red ones Are areas that we have completed reclamation and the areas in yellow are the ones that we're still working on um so the total site is over 300 acres, but um Total unreclaimed is a little less than 197 that this chart shows because we've been working on Bluff B right here, which is the biggest so, um Bluff B is about 153 acres. So it's going to take us several years to take care of that. Um, and I got some pictures. So Here's bluff G In the left hand picture. This is the early stages of reclamation. They're using excavators to load up dump trucks to haul the waste to The repository and then you can see in the bottom of the photo. We've constructed a road to facilitate Um transporting that material In the right hand picture is the completed Um the reclaimed area but without vegetation and you can really see the detail of this complex topography Um slowing down that water as it drains off um the side slopes of that butte So here's a good before and after so on the left side. This was after mining but before any reclamation was done you can see We just have a lot of erosion no soil no vegetation has grown And then on the right hand side is after reclamation when the vegetation has grown in there's probably between three and five Um three to five years between these photos And then bluff I of course on the left side Is after mining but before reclamation And you can see that road Had been constructed to transport material and then on the right hand side is um After mining or after reclamation Once the vegetation has grown in Here's a before picture of bluff b um we're working on this now But you can just see the lack of vegetation And just the slumpy sides covering up those sandstone cliffs This I took last year um at bluff b and I think it's a really good example of Here's the un reclaimed area And this is the nice beautiful clean soil All these stockpiles this was taken in the middle of reclamation. So they've Built the landforms, but then they have all this stock piled material on top With the clean material that they're going to use as The 18 inches of clean material that we put over all the landforms. So that's why it looks like that So I'm on the final final picture, but we did seed this area last year Um, and I'm excited to see what it looks like this spring. Hopefully we get lots of plants growing with how wet it was last year So then we are monitoring vegetation Um out at the site and this table shows On the right hand side. These are our comparison areas And these are the undisturbed non-mined areas that we are using to compare natural vegetation at the site to our reclamation areas. So These areas are the reclaimed areas And then on this side the bluff name along with the year that reclamation was completed and they were seeded The reason there's a line between 2020 well 2020 2021 and 22 and 23 is because we kind of changed our monitoring techniques, but even if you look at 22 and 2023 we have higher Areas of cover versus non-cover even compared to our comparison areas. So we're doing pretty good vegetation wise And then of course we're also another method of evaluation we're using species richness and then Species riches and diversity Um, so once again, we have our comparison areas over here These are our readings for the eight bluffs that we are currently monitoring And you can see that our numbers are either the same or they're a little bit higher for our reclaimed areas versus our comparison areas So we're pretty happy with it Future work at the site. So as I said before we have three Remaining bluffs requiring reclamation. We're working on b which is pretty big. We're going to be working on it for a while and then we also bluffs h and l and then as part of This reclamation the work includes designing the excavation design Where's the hottest material and then our consolidation design? Where are we going to put the hottest material? And then on top of that we're designing the landforms to make the area more stable Overtime and indistinguishable from the surrounding landscape And then of course on the bluffs that we've reclaimed So far we're doing We're making sure that the vegetation is stable. We don't have a lot of invasive species coming in And we don't have a lot of slumping or erosion happening And then we're also monitoring sediment. So we're comparing the sediment that's eroded from bluff B pre reclamation And then we're going to be taking measurements over time as we reclaim it and compare how much sediment Is being eroded from bluff B as we reclaim it and anchor that material with vegetation and then of course we do site maintenance as needed which is Taking care of the roads at the site so we can access these different areas dealing with culverts dealing with um spraying invasive weeds Or planting trees in certain areas to kind of get everything to grow back So how do we measure success at the site? As I said before we do verification sampling to make sure we're meeting our cleanup goals for the contamination at the site And then we're also monitoring sediment, which I showed you our tables of the last few years Making sure that we don't have invasive species taking over and we say we have good vegetation growth But it's really invasive species. We don't want those. So we want to get native Plants there and one thing I forgot to say earlier. It's taking two to three years for plants Yeah, two to three years for the plants in our seed Seed mix to really become established at the site Um, and then we're doing the sediment monitoring trying to monitor hopefully how much less erosion we have as we complete our reclamation and increase our vegetation growth Um, and then of course house our vegetation over time you might get you know the first year Of reclaiming an area as you guys probably all know You might have a few dominant species But then over time more species will come up. So we'll have a good variety at the site And then making sure that these landforms are stabilized and not failing. We don't have erosion We don't have gullies forming. So making sure everything's really stabilized And I think I probably have time for some questions Okay, good. Yeah Thank you We actually we so we've done some studies in the area on neighboring properties and we've identified cover borrow areas. So We've done a lot of testing in these areas But they're they're just areas off the forest service land on private property where we have an agreement with the landowners To take that top soil Which isn't great, but it's what's out there. So we're trying to really match the surrounding area So we take that material and um haul it from local areas. So we're not we do um amend that soil with some Compost that we do bring in so that's imported in But otherwise the most of the borrow is taken from neighboring areas We haven't sampled the in the reclaimed areas. We haven't sampled that vegetation But we did before we started the work. We did do um A risk assessment study and I'd have to go review that and I can you have my contact information So I can I can get that to you, but we did um evaluate that in our risk assessment um Can you explain again what you did with the hot stuff that used to use and did you try to refine them into different Like the same repository or did you do it pretty much on each view? Generally on each butte it's kind of dependent on our scope of work is I don't know of you Don't say we can go back, but I mean we combined let's see so This is bluff cd and e which just grew bigger and bigger that we just kind of combined it into one butte So that has one repository on it even though it's three bluffs but generally each bluff We're pulling the material From the side and putting it on top but then making sure we're encapsulating it deep enough that nobody's going to dig into it and um the the radioactive material Is blocked by that clean cover soil that's on there And then we do the sampling on top of that to make sure that all that material on that surface Meets our cleanup goals Does that answer it? Yeah, so I'm I think I might have missed it and you pull it up on top. Do you? Is that where you? Yes, because that's where it originally came from when they were mining They just scraped off that top and pushed it to the edge of the bluff or off the side of it So we're putting it all back where it started Thank you so much