Locking your food in a truck cab is a good way to one day find your truck destroyed. If you have no trees to hang your food you should dig a cash and put steel doors on it with a heavy lock. Bear spray is not made to be sprayed around as a deterrent it is a last resort made to be sprayed in the bears face so that its eyes burn so badly it can't see and it has a hard time breathing. It sounds to me like you are no where prepared enough to be doing what you are doing in an area that has predators that kill and eat humans and you need some expert advice on how to do it. I suggest you contact the wildlife agency that has jurisdiction of the state you are mining in. Those animals are doing what they do, you are in their backyard and you need to learn how to safely be there and how not to attract trouble to the best of your ability. You don't say what kind of shelter you are living in or if you have bear proffed it.