Don't worry about that, they were common at plants down in Texas. We had one or two log washers at each of our 15 or so plants back in the 80's. Our company, at that time, used machines made by Eagle Iron works. We usually were mining sand and gravel that had a very high clay content, so the log washers were used to get everything cleaned and separated out, after it want over/through the primary screen. We then discharged into a secondary screen and then all the fines went into the sand classifier. (I think, it has been 35 years or so). I do know we could not have produced spec sand and gravel without the log washer in the process, as we had very muddy material. Can not help with costs and such, as it has been too many years ago.