UPDATE 1-Barrick Gold earnings in line with forecasts, output seen falling

(Recasts with adjusted earnings; adds production, cost forecast, analyst forecast)

Feb 14 (Reuters) - Barrick Gold Corp reported adjusted fourth-quarter earnings on Wednesday in line with market expectations and forecast gold production dropping over the next four years with mining costs seen flat to higher.

Barrick, the world's biggest gold producer, said it expects to produce between 4.5 million and 5 million ounces of gold this year at a cost of between $765 and $815 an ounce on an all-in sustaining basis, the industry benchmark.

That was down from output last year of 5.32 million ounces of gold with comparable costs in 2017 of $750 per ounce.

Based on its currently-held assets, Toronto-based Barrick said it expects to produce an average of between 4.2 million and 4.6 million ounces of gold a year between 2019 and 2022 at all-in sustaining costs of $750 to $875 per ounce.

In the fourth quarter, Barrick's adjusted net earnings were flat at $253 million, or 22 cents a share, from $255 million, or 22 cents a share, in the same period a year ago.

Analysts expected the company to earn 21 cents a share, according to Thomson Reuters I/B/E/S.

On a net basis, Barrick reported a loss $314 million, or 27 cents a share, as it wrote down the value of unmined gold at a stalled project in South America after its plans for how to develop the mine changed. (Reporting by Nicole Mordant in Vancouver; editing by James Dalgleish, G Crosse)