Freeport-McMoRan reported a fall in fourth-quarter copper output and said it expected higher spending in 2020 as it transitions its giant Grasberg copper mine in Indonesia to underground mining, sending its shares down 9%.

The US miner has spent billions of dollars in the switch from a depleting open pit mine and to develop a coexisting underground mine that would help achieve low cost, long life production and generate significant future cash flows.

Copper production at Grasberg fell 14% in the fourth quarter, while total production of the metal dropped 1.7% to 827-million pounds.

The company said it expects capital expenditure for 2020 to be about $2.8 billion, higher than last year, including $1.8-billion for major projects. It has also earmarked another $500-million for the development of a new smelter in Indonesia.

“We think the market has taken a very short term view of 2020 and focused on the capex related to the smelter, the first quarter guidance and the cash costs”, said Deutsche Bank analyst Chris Terry.

Unit net cash costs are expected to average $1.75 per pound of copper for 2020, the company said, compared with $1.74 last year.

Freeport forecast sales of 725-million pounds of copper and 105 000 oz of gold in the first quarter.

CEO Richard Adkerson said copper will benefit even during modest global growth, but added current prices are still well below the incentive needed to attract new supply.

The average price Freeport received for its copper fell marginally to $2.74 per pound in the fourth quarter.

Copper prices have rebounded as a Phase 1 trade deal between the United States and China eased pressures on the red metal. Prices for copper, often seen as a gauge of economic health, posted the biggest monthly gain in two years in December.

Net income attributable to shareholders fell to $9-million from $485-million in the three months ended Deember. 31, as the company booked a tax provision of $329 million, compared with a benefit of $552 million in the year-ago period.

Excluding one-time items, Freeport earned 2 cents per share, while analysts had expected break-even, according to IBES data from Refinitiv.