SYDNEY, Feb 28 (Reuters) - London copper steadied on Friday after comments from Federal Reserve Chair Janet Yellen eased concerns about the U.S. economic outlook, but London copper is expected to end the month flat as worries about a slowdown in China's economy play a role. Do not go.  
   Yellen said on Thursday that the unusually harsh winter appeared to be contributing to recent signs of weakness in the U.S. economy. This suggests that the central bank will continue to reduce stimulus measures.   U.S. durable goods orders excluding transportation and a measure of business spending unexpectedly rose in January, raising hopes that manufacturing activity has slowed in recent months.

   "The global economy has been weak, as has China and the US - although in part the weather has contributed to the downturn in the US. It's hard to say what will significantly support prices going forward," said National Australia Bank analyst James Glenn. .

   Three-month copper on the London Metal Exchange was up at $7,034.25 a tonne by 0726 GMT, after closing almost flat in the previous session, when it fell to a near three-month low of $6,993.50. Copper in London traded as low as $6,995 a tonne on Friday. 
   Copper on the LME has erased February's gains and is nearly flat for the month, down more than 4 percent so far this year.

   The most actively traded May copper contract on the Shanghai Futures Exchange slipped 0.12% to 49,280 yuan a tonne. The contract had fallen to 48,930 overnight, its lowest level in seven months.

   Market attention now turns to Chinese economic data and next week's two sessions. Over the weekend, China is to release manufacturing data.

Worries about emerging markets were further fueled by news reports earlier on Friday that an unidentified group of armed men had seized the Crimean capital Simferopol International Airport.

   China's manufacturing activity is expected to expand only marginally in February and the official manufacturing PMI is expected to fall to an eight-month low in February, a survey showed, adding to evidence of a slowing economy. The data will be released on Saturday.

China's economy is expected to grow 7.5 percent this year, but it is also possible if it is revised to 7 or 7.25 percent, Glenn said.

   U.S. Freeport-McMoRan copper-gold mine said its Indonesian operations may need to declare force majeure on copper concentrate sales due to regulatory changes in Indonesia.

   "The market is not expected to react positively to this."

   Tin prices are expected to record a 7% gain this month, supported in part by a supply ban in Indonesia.

   The only domestic tin trading platform in Indonesia has set a "recommended opening price", which provides guidance for the trading price, but does not serve as the minimum trading price for tin futures.

   Global markets other than China have eased pressure on tighter copper supplies. Spot copper traded at a premium of $61 a tonne to benchmark copper futures, retreating from a 22-month high of $78.50 hit in the previous session.