08:46 AM EST, 03/01/2018 (MT Newswires) -- First Majestic Silver (FR.TO) dropped 3.2% in premarket New York trading after the company said it swung to a fourth-quarter loss on charges, lower silver production, higher costs and weaker prices.

The company said it lost US$56.1 million in the quarter, or US$0.34 per share, compared with a year-prior profit of US$1.8 million, or US$0.01. It attributed the loss to a US$42.4 million writedown on its Del Toro silver mine. It pegged its adjusted loss per share at US$0.04 but offered no additional detail.

First Majestic said its silver-equivalent production in the quarter was 4.07 million ounces, down 7.2%, while all-in sustaining costs were 9.5% higher at US$14.13 per ounce and its average sale price dropped 3% to $16.61 per ounce.

The company, which operates six mines in Mexico, said it expects higher output this year

"Investments made in 2017 are expected to generate double digit growth in silver production in 2018 primarily due to higher underground production rates at Santa Elena and Del Toro. higher silver grades from caving and the start-up of the new roasting circuit at La Encantada," Keith Neumeyer, the company's chief executive, said in a statement.

First Majestic was down US$0.17 to US$5.14 in premarket trading. The shares closed Wednesday at $6.80 on the Toronto Stock Exchange.