* Copper production rises 4 percent
* Q1 total output down 6 percent
* Minas-Rio iron ore mine ramp-up ahead of plan - CEO (Adds analyst comments, graphic, updates share move)
By Muvija M and Barbara Lewis
April 25 (Reuters) - Anglo American said on Thursday technical problems dragged first-quarter production down 6 percent, but copper output rose, as did that of iron ore from its Minas-Rio mine in Brazil, which ramped up operations after a leak last year.
The share price fell 1 percent by 0908 GMT. The stock extended losses from the prior session, when JPMorgan warned of a $900 million cut to 2020 core profit if Minas-Rio failed to obtain a Brazilian tailings permit by the end of the year.
Brazilian authorities have increased scrutiny following the Vale dam disaster in January.
JPMorgan downgraded the stock to "neutral" from "overweight", saying the share no longer looked cheap. It has gained nearly 20 percent this year, outperforming some peers.
Anglo American's strength has been driven by increased productivity and a promising outlook for copper as the mineral is in demand for an anticipated upsurge in electrification.
Anglo's Copper output climbed 4 percent to 161,100 tonnes for the three months ended March 31, the miner said. Minas-Rio iron ore production jumped 61 percent, following a faster-than-expected ramp-up.
Anglo American in December restarted operations at Minas-Rio, after getting regulatory approval to step up production. At the same time, it increased production targets for 2019, but it still needs another permit.
On Thursday, Chief Executive Mark Cutifani said the fall in total output had been offset by a strong performance in copper.
"By the end of the quarter we had increased our production run-rate, are on track to deliver this year's production targets and our guidance is unchanged," Cutifani said in a statement.
Many analysts broadly agreed. Edward Sterck of BMO Capital Markets maintained his "outperform" rating, saying Anglo American remained his top pick among diversified miners.
Smaller peer Antofagasta posted a 22.6 percent jump in first-quarter copper production this week, bolstered by better-quality ore.
Reporting by Muvija M in Bengaluru and Barbara Lewis in London; additional reporting by Zandi Shabalala; editing by Dale Hudson and Gopakumar Warrier