(Adds details on production, context)
MEXICO CITY, April 28 (Reuters) - Grupo Mexico's first-quarter profit fell just over 6 percent as a drop in copper prices hit revenue even as production increased, the company said on Tuesday.
Grupo Mexico said first-quarter profit fell to $372.6 million from $397 million in the year-earlier period.
The company said despite a 7 percent increase in mining output, revenue for the January-March period was $2 billion, down 3.92 percent from the same quarter last year.
Grupo Mexico said copper production rose 7 percent during the quarter, compared to the year-earlier period, while zinc output dropped 27 percent. Silver production fell 8 percent, while gold output was up 8 percent, it added.
The company's transport division recorded sales of $462 million, up nearly 2 percent from the same quarter last year.
At the end of the last quarter, the company said it hoped to list its ITM rail unit by the first half of this year. The company expects to raise $1.3 billion with the offering, which would provide investors a proxy for investing in Mexico's booming auto sector.
The company also said its first-quarter results were affected by $6 million in costs related to last year's toxic spill at the Buenavista copper mine in the northern state of Sonora.
Grupo Mexico has spent a total of $97 million on spill-related costs, it said.
Nevertheless, the company is currently investing $3.4 billion to expand capacity at the Buenavista mine, it said.
Grupo Mexico's shares traded down 0.04 percent at 47 pesos per share on Tuesday morning. (Reporting by Joanna Zuckerman Bernstein, Michael O'Boyle, and Gabriel Stargardter; Editing by Meredith Mazzilli)