Okay, so what you will need is the harvest basket, if you don't have it, purchase it from jeff at the store. What you need to do is, take your basket to the the mine. And, just start mining, everything you get from digging, just throw in the basket, I'm pretty sure you can have up to the 30 things in that basket, and you still have room in your rucksack. Make sure that when you dig and you find the stairs that go down, take your basket with you. When your done, you can take your basket back to the farm and sell it all, it gets you waaaay more money this way!
Hope I helped
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