I bought some BTC on Coinbase last night and had it sent to Poloniex. I know the BTC wallet address was accurate. Its still pending 11 hours later and doesn't show up in the Poloniex deposit/withdrawal history. Any clue on how long BTC transactions are taking?
Typically a bitcoin delivery transaction depends on how many unconfirmed transactions you can see here
https://blockchain.info/unconfirmed-transactionsAnd usually also depends on how much fee you provide for the fee, the greater the fee you give the faster bitcoin delivery process.