* Q4 iron ore sales volume up 26 pct to 7.8 mln tons in U.S.

* Q4 revenue $1.28 bln vs. est $1.21 bln

* Shares up 11 pct after market (Adds details on iron ore sales, share movement)

Feb 2 (Reuters) - Miner Cliffs Natural Resources Inc reported a 26 percent jump in quarterly iron-ore sales volumes and lower production costs in the United States as it continued to cut jobs and related expenses.

Cliffs Natural Resources shares rose as much as 11 percent to $7.70 in after-market trading.

U.S. iron ore pellet sales volume increased to 7.8 million tons for the fourth quarter ended Dec. 31, while cash production costs for iron ore fell 5 percent to $59.06 per ton.

Iron ore miners are struggling to survive weak prices as low demand for the steel-making ingredient in both domestic and international markets continues to weigh on their results.

Cliffs Natural moved to stop production at its loss-making Bloom Lake iron ore mine in Quebec in November, helping it cut its fourth-quarter capital spending by more than half.

Last week, the company scrapped its quarterly dividend and sought creditor protection for its Canadian arm, which will shield it from the majority of the closure-related costs.

Cliffs is the third major U.S. company in the past six months to seek creditor protection for their Canadian operations. U.S. Steel opted to do the same in September, while discount retailer Target Corp said last month it was abandoning its Canadian expansion.

Cliffs took an impairment charge of $1.2 billion, partly related to the exit from Canada, leading to a fourth-quarter loss of $1.26 billion, compared with a profit of $30.5 million a year earlier.

Revenue fell nearly 15 percent to $1.28 billion, but edged past average analysts estimate of $1.21 billion, according to Thomson Reuters I/B/E/S.

Up to Monday's close, the miner's shares have lost nearly two-thirds of their value over the last 12 months. (Reporting By Kanika Sikka and Manya Venkatesh in Bengaluru; Editing by Joyjeet Das)