[Faramir Jones]

This was what Tolkien had to say about Gollum’s stay in Moria, after his escape from Thranduil’s realm, pursued by Elves and Orcs, according to ‘The Hunt for the Ring’ in Unfinished Tales:

What then happened to Gollum [in Moria] cannot of course be known for certain. He was peculiarly fitted to survive in such straits, though at cost of great misery; but he was in great peril of discovery by the servants of Sauron that lurked in Moria, especially since such dire necessity of food as he must have he could only get by thieving dangerously. No doubt he had intended to use Moria simply as a secret passage westward, his purpose to find ‘Shire’ himself as quickly as he could; but he became lost, and it was a very long time before he found his way about. It thus seems probable that he had not long made his way towards the West-gate when the Nine Walkers arrived. He knew nothing, of course, about the action of the doors. To him they would seem huge and immovable; and though they had no lock or bar and opened outwards to a thrust, he did not discover that. In any case he was now far away from any source of food, for the Orcs were mostly in the East-end of Moria, and was become weak and desperate, so that even if he knew all about the doors he still could not have thrust them open. It was thus a piece of singular good fortune for Gollum that the Nine Walkers arrived when they did. (My emphasis)