This works! Try it!
1. Find node. Ck for nearby trollhouse and put a workbench inside entrance just for giggles. Kill troll.
2. Take down trees over top of copper and around edges. Leave them as logs and push off node. Makes for pathing issues with enemies.
3. Go right up against node with your pick and dig the ground straight down and even a little under the node if you can. Once you get to BEDROCK, don't stop before that, then start going right or left all around the node as deep and close to node as possible. Do NOT hit the node.
4. When you have made complete circuit decide whether you want to put your portal down there, a chest and campfire. If you do there is possibility of event. If you are getting troll events this might be iffy, or not, your call. If you already have a safe spot a bit away really don't need to do this.
5. Start working on node and clear it out around the edges a bit. They still won't be able to get to you, you might get a troll every day or two. Go to center top and dig down so you are shielded by copper and clear it all out in a logical manner.
6. Go home at night or figure that you will call in mobs. Good target practice. Have fun. You should have no more problems.
Hot tip: Mine silver from underneath too, Nothing can reach you and when vein is fully released from dirt one or two good taps and it all comes tumbling down. Very fast method.