(2nd LD) Industrial output, retail sales, facility investment down in Aug.

(ATTN: ADDS details in paras 6-7) By Kang Yoon-seung SEOUL, Sept. 30 (Yonhap) -- South Korea's industrial output lost ground in August from a month earlier, data showed Wednesday, with retail sales and facility investment also backtracking in a triple whammy for the first time since May. Industrial production lost 1. 3 percent from a month earlier in August, according to data from the Ministry of Data and Statistics. Output in the mining and manufacturing sector, a key pillar of the economy, slipped 4.