The ancient city requires 2 key items:
1) The big bone can be obtained by defeating the big skull enemy. One spear and some kiting is enough to kill it. Make sure to save beforehand.
2) The other item can be crafted in the key crafter. To craft the key crafter, you need an egg, which can be obtained from defeating the big bird. The item costs 3 glass and 10 gold, which can be smelted in a furnace with 6 sand and 20 gold ore.
The Miner and Lumber achievements can be easily obtained in the tutorial. Start the tutorial by clicking on new game in the menu, collect the 2 eggs, mine the gold ores, and smelt them. You will have enough resources to craft either the miner or the lumber. Craft one of them and then reload the tutorial.
Caution! Currently, loading a save destroys items in backpack mutations. Do not carry any important key items in these slots.
