carter 3 Report post Posted December 16, 2014 Seems like ive read before of people saying an average% loss of excavator/trommel vs a dredge(say a typical 6" modern) I know many variables here but do plan on moving from dredge to mini excavator/trommel and afraid of not getting much into the bedrock with 9,000lb machine. Anybody make the transition from dredger to mechanical and notice a % loss? jay Share this post Link to post Share on other sites
Reno Chris 101 Report post Posted December 16, 2014 So many, many variables here its tough to give a meaningful answer - what is true of such a comparison in one place could be completely untrue in another. Really and sincerely an apples to oranges comparison. Dredges work in the water, excavators work mostly on dry land, though some water can be in the gravels. Most environmental authorities would not want you using an excavator in the flowing water of a stream. In some places bedrock is weathered, and so digging into it is no problem and operators will take a couple feet of bedrock to get all the crevices. In other places bedrock is hard and even with the biggest bulldozer on the market you are not going to efficiently rip that hard, solid bedrock. Share this post Link to post Share on other sites
mendoAu 1 Report post Posted December 22, 2014 Best of both worlds, excavate/washplant/trommel what you can and then longarm the bottom with a dredge/combo. And if you are worried about the % of loss rework your tailings....the big cobbles are already out of the way. Share this post Link to post Share on other sites
carter 3 Report post Posted December 22, 2014 I agree with you all the way chris, my bedrock is mostly vertical fractured schist so their is very good gold 24" into it that I have dredged. Once the first pieces are bared apart its like a puzzle, quit fun. Once the material is mined I don't want to rehandle the tailing except for reclamation. Gold will be out of it if I build the tromel/sluice right anyways. I have to move creek to mine that spot under a APMA .Once done in that section and creek back I wanted to dredge the bedrock.(If I can keep the tailings from covering it) Share this post Link to post Share on other sites
Ricky D N 7 Report post Posted January 5, 2015 Actually it has more to do with how many yards of material you process in a day, that is the determining factor , you still have to do a clean up on both pieces of equipment , with the trommel you won't be all wet !! Share this post Link to post Share on other sites
Geowizard 122 Report post Posted January 12, 2015 If the gold is in a river, creek, lake, pond or other water - it is either on or near bedrock. - Geowizard Share this post Link to post Share on other sites
rjcjid 6 Report post Posted February 9, 2015 Geowizard, You have studied the Ophir/Ganes Creek area. I imagine that you have seen/studied the bucketline dredge tailings. Do you believe that the dredges were efficient in tearing up the bedrock to get the gold? Is there a lot of bedrock on the top of the tailings piles? How easily is the bedrock in that area ripped? Thanks, RJ 1 Geowizard reacted to this Share this post Link to post Share on other sites
Geowizard 122 Report post Posted February 9, 2015 RJ, Excellent question! Every tailing pile tells a story! - Geowizard 1 rjcjid reacted to this Share this post Link to post Share on other sites
rjcjid 6 Report post Posted February 11, 2015 Geowizard, I've seen a lot of bucketline dredge buckets and used to operate the dredge at Platinum AK. I've never seen a dredge bucket with something along the lines of a ripper tooth attached. I would think a ripper tooth of 4" to 6" deep would work good on bedrock like sandstone or shale/slate. Your thoughts? RJ 1 Geowizard reacted to this Share this post Link to post Share on other sites
Geowizard 122 Report post Posted February 11, 2015 RJ, Wow, you have some interesting experience! I'm sure the original designers were approached with that idea. - Geowizard Share this post Link to post Share on other sites
Got the bug 6 Report post Posted February 12, 2015 If I can figure out how to post photo's, I have some good pic's of a couple of Steam Donkey's that I took while prospecting in the old Fortuna Ledge Mining District this past fall. As well as some other old mining equip. 1 Geowizard reacted to this Share this post Link to post Share on other sites
Geowizard 122 Report post Posted February 12, 2015 Cool! I was going to mention the first dredges (1600's) were powered by manpower! - Geowizard Share this post Link to post Share on other sites
chickenminer 42 Report post Posted February 13, 2015 . I've never seen a dredge bucket with something along the lines of a ripper tooth attached. I would think a ripper tooth of 4" to 6" deep would work good on bedrock like sandstone or shale/slate. RJ I have but it was used on an old Dipper dredge. I don't think the design proved worthwhile on bucket line dredges because of the added maintenance other parts incurred. There is a string of buckets in the woods along the South Fork of the Fortymile that have teeth. If I remember they were small size, not home brew affair but manufactured. I have photos somewhere ... if I could ever find them! 1 rjcjid reacted to this Share this post Link to post Share on other sites
rjcjid 6 Report post Posted February 15, 2015 ChickenMiner, I would agree that they would most likely be a very high wear item, but the ripper teeth on a Dozer are a high wear item as well. I've been on a bucketline dredge when it was scraping bedrock, every passing bucket rocked the dredge. I can't imagine what kind of reaction there'd be if a ripper was added to the buckets. RJ Share this post Link to post Share on other sites
