PRECIOUS-Gold slips as U.S. 10-year yields hit highest since mid-July

* Dollar gains as U.S. yields rise, Spanish tensions pressure euro

* Speculative investors cut net long positions in gold

* GRAPHIC-Platinum/palladium ratio: http://tmsnrt.rs/1QjSZAC

(Updates prices) LONDON, Oct 2 (Reuters) - Gold fell to its lowest since mid-August on Monday as rising U.S. Treasury yields pushed the dollar higher while concern over violence during Catalonia's independence vote at the weekend weighed on the euro. U.S. 10-year Treasury yields hit their highest since mid-July on expectations that the Federal Reserve will increase U.S. interest rates for a third time this year, upbeat U.S. data and talk of a possibly more hawkish successor to Fed Chair Janet Yellen. Rising yields increases the attractiveness of bonds compared to gold while strength in the dollar makes assets priced in the U.S. currency more expensive for buyers holding other currencies.

Spot gold was down 0.3 percent at $1,275.81 an ounce nearly seven weeks. U.S. gold futures for December

delivery were down $6.30 at $1,278.50. The metal posted its biggest monthly fall this year in September despite a quarterly rise of 3 percent, lifted in part "The recent sell-off is mostly related to a stirring of the reflation trade following the announcement by the Trump administration of the long-awaited tax reform proposal," Mitsubishi analyst Jonathan Butler said. "The dollar has jumped to six-week highs, Treasury yields have surged to three-month highs as investors search out risk assets and U.S. equities reached new record highs on Friday." The euro also came under pressure after Spanish police used batons and rubber bullets in an effort to thwart an independence vote in Catalonia on Sunday, leaving hundreds injured. The single currency was down 0.6 percent versus the dollar. With European bourses opening higher, gold failed to benefit from increased demand for havens from risk. Speculators cut their net long positions in COMEX gold and silver contracts in the week to Sept. 26, U.S. data showed on Friday.

Among other metals, silver was up 0.5 percent at

$16.68 an ounce after marking its lowest since Aug. 9. Platinum

rose 0.1 percent to $910.50 and palladium was down

0.6 percent at $930.75. Platinum held in a historically unusual discount to sister metal palladium for a fourth session. "There is arguably speculative froth in the palladium price, so a short-term correction is likely," GFMS analyst Ross Strachan told the Reuters Global Gold Forum on Monday. "However, the longer-term picture is one where the sharp downward path for stocks of palladium mean that eventually (it) is likely to reach a sustained premium over platinum. Our new forecasts show that on an annual average basis we expect palladium to exceed platinum in 2019."

(Additional reporting by Apeksha Nair in Bengaluru; Editing by Susan Fenton and David Goodman)