Most will recommend to not use the cart and only use 1 crate at time, just running back and forth. with default agility or maybe a little higher - you move about the same speed - and don't have to deal with any of the glitches associated with the cart.
The cart is really more of a....Optional... feature at the moment.
It's known buggy.... but to just "disable" it would mean the option of taking the risk to maybe get a /lot/ of ore, isn't present.
Personally. I rarely see a need for more than one light-source filled crate - If I ever saw a point that I could maybe manage 3+ crates in a single run - I would /maybe/ set up the cart to be used to transport it....
But I'd honestly probably just leave the other 2 crates of ore in the corner of the mine while I take one crate back and smelt and open shop for a bit, then go back for another crate before bed - its 24hrs in game (I assume at time of depletion) that depleted veins change over, so usually, That ore is a few trips worth, anyway, and I won't be mining anything the next day, regardless if its picking up the last crate, or just checking veins.
Having to go back for ore gives me more sense of purpose in the trip over though, instead of being disappointed when none of them are new or good.
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Associated with cart
- riding shatters player sheet/orientation to some degree.
- Heavily Physics sensitive, You're lucky that pole grip fell in, and not sent the cart and crates skyrocketing off into the distance.
- If it shatters Player orientation/height enough - can leave the player "swimming" (sliding) inside the ground or high in the sky.
- (point 1 and point 3 can be fixed with Slipcor's Reset Player model, point 2 can partially be fixed with Slipcor's Reset Horse/waggon - "fixed" is a "reset", not a "It doesn't break anymore")
- Ish kinda slow... it really should be more than two crates a trip...
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more towards your issue
- Try jumping onto the cart (manually, not riding) till you can see inside, there's a couple areas you can, and jump-crouch may help further. - then you can have an easier time seeing grabs.
- Simply fish around from the side for a "highlight" and grab - You can grab things, within some level of reason, through the cart and other solids, and then move them around that object/solid.
- Be careful and good luck.