We rarely take a field trip, but a local woman who recently began homeschooling her son organized a trip to the Echo Coal Mine, just north of Reefton, this month. The mine manager (her brother) gave us a fascinating peek into the running of an open-cast coal mine. We all very much enjoyed it, and learned a lot!
Because there were so many in our group, we were divided into two tours. Our family waited in Reefton with some friends while the first tour happened. We spent some time in the museum part of the local I-site (information center), and then walked out of town a little way to the swing bridge over the Inangahua River before eating our lunch. You can see from these photos that we had a beautiful, sunny day.
After we ate lunch, we drove up to the road that goes into the mine. We found this shed, and parked beside it to wait for the first tour to return. A truck went past, hauling coal down from the mine to the railroad, and someone who was near the shed heard the driver inform the manager, via radio, that there were people at the red shed. He replied that he knew about it; they were waiting for a tour.
Soon, the first group came back down, and it was our turn. We reorganized a bit so we didn’t have to take so many vehicles up; two of our boys rode with the manager in his ute, and we followed him up the road into the mine.
When we came to a stop in front of the office, we looked out over the processing area. The coal is brought in here. After it is dumped out of the trucks, it goes through the sorter. The large pieces are used for heating buildings, mainly, or processing milk powder. The dust, which, if I remember right, comprises about 80% of the end product, mainly goes to Japan, where it is made into such items as silicon chips for cell phones and computers, or turned into carbon fibre for bicycles and dialysis machines, among many other uses. He rattled off so many things I couldn’t remember them all!
We went into the office next, for a slideshow of the history of the mine, and photos of scenes from the past 12 years or so. The rock layers they have uncovered are amazing! So is the view from his office…rough life, to have to work in a place with a view like this, isn’t it!
Our next stop was to see what the mine is doing to rehabilitate the area after mining it. All the tailings are dumped in mountains, and reshaped similarly to the natural mountains. Then, the mine has a local helicopter company seed the slopes with lotus grass (actually a legume) that grows in the rocks and fixes nitrogen in what little soil there is. A year later, they plant native trees among the grass. Our guide also pointed out the smoke from a mine that caught fire in the 1960s and has been burning ever since. DOC (the Department of Conservation) now owns it, but won’t do anything about putting out the fire. It burns 20-30,000 tons of coal a year, if we understood correctly.
Finally, we got to see the mine itself! These photos don’t come anywhere near showing the magnitude of this pit. It is huge! Can you pick out the digger and dump truck just left of center? The red dot over the middle of the pond at the bottom is a ute (pickup truck), and down a little from that, right of it, is a smaller, blue digger sitting on a coal seam. And look at those layers! We discussed later how they must have formed during the Flood, as sediment washed in on tidal waves, covering mats of trees and other plant material, followed by more layers… and then, while it was still soft and wet, seismic activity folded the layers. So amazing!
Our guide told us why the water in the pond has such a beautiful color. It has a pH of about 3.2. Iron sulfites leach into the water from the mine, creating sulferic acid. They have to neutralize that before letting the water go back into the environment. At first, they treated it with lime, but then discovered that mussel shells work even better, for much less cost! In fact, when Esther took the video below, she caught part of that discussion!We went from the mine to the dumping spot, to watch a load of dirt and rocks be dumped. Little Miss found this quartz rock and wanted me to take a picture of it. In the video you can see the truck being loaded, and then the same truck dumping. The bulldozer is there all day, smoothing off the area, building the “wall” around the edge to keep trucks from going over, and being there in case a truck would back up too far, to pull it out. It didn’t sound like that has happened much, if at all, though.
Our last stop was down at the bottom of the area they are rehabilitating right now. This is a close-up of some of the lotus grass. This area has been growing for a number of years, and there are several inches of rich-looking soil there now on top of what used to be bare rocks.
Here, the children got to climb on a digger and a bulldozer. They enjoyed that opportunity! This is a 75-ton dozer; we didn’t catch the size of the digger. It’s enormous, though!After we followed our guide out of the mine, we asked about these fords we noticed beside the bridges. They are for the heaviest machinery to go through—anything over 40 tons or so.