Hobgoblin mine at level 31 wilderness. You'll need to dig at the location shown in the map below while having the clue scroll and navigation tools in your inventory. Be ready to fight lvl 65 wizard that will attack you with the flames of zamorak spell, you'll need to use the protect from magic prayer. Avoid bringing items that you are not prepared to lose. If you are attacked by another player you can teleport away unless you're above level 20 wilderness, at higher levels you have to log out before you are being attacked.

Required items: clue scroll, watch, sextant, chart, spade, weapon, two pieces armour, anti poison, teleport runes and food.

Required quests: none.

Possible way of transport: Walk North-East from the chaos temple near Goblin village, go past the Dark knight fortress and Bandit camp or walk North-West from Varrock go past the Graveyard of shadows and the Ruins.