We are looking at a job where everything looks pretty straight forward but for the pnuematic stowing. I have done as much searching as I could and still haven't found a company that does this near us. Also would like to see what the equipment looks like and how hard it is to do this. Any info from you folks would be great.
Well buckfever, I will have to do some investigating for you. We just did a Maronda plan in the south hills where a lot of the home sites are getting that, but they called it mine groutting, never heard of pnuematic stowing before. I googled it, sounds the same. I would like to see it but have since moved to the next job, so won't be around to see it.
Sure seems like they did that on Dirty Jobs show. They filled the hole with foam boards and they used two component foam to seal the top with. Just guessing you could do the same thing with the foam board and then spray a cementitous material or shotcrete over the foam?
This prosess is a little different then grouting. You basicly make the worlds largest potato gun. Using a 6" plastic pipe you slide the pipe in as far as the engineer says then you make a T out of a Y and a 45. The leg of the T is pointed up and a hopper is attached, this is where the gravel is dumped. On the back of the T you hook up a very large air compressor (about 1500 cfm at 120psi). The air blows the gravel into the mine shaft up to 70 feet from the pipe. There is not cement involved and the stone is moving so fast that it compacs it self. The stone has to be limestone and acts as a filter to reduce the amount of acid in the water. Once you read about how it was done it seems pretty simple but would just like to find someone with firsthand expirence.
Gotcha Buck, I did go back and continue reading about the process, sorry its not the same sounds close though. Seems like an interesting process.