Australian exports of iron ore to China via the Port Hedland terminal dropped to a seven-month low in November from a near-record the previous month, port figures showed on Tuesday.

Iron ore miners are under fire from government and private industry for flooding China with cheaply-mined ore and driving iron ore prices to 5-1/2 year lows.

Shipments to China from Port Hedland, which handles about a fifth of the world’s seaborne trade, dropped to 29,027 million tonnes in November, the lowest since April and 8 percent under October’s tally of 31,714 tonnes.

On a year-on-year basis, November shipments to China rose 30 percent, according to the port.

Australia’s biggest producers, Rio Tinto and BHP Billiton both reported record iron ore output in their latest quarterly reports, and affirmed they were on track to boost production even further.

No. 3 producer Fortescue Metals Group, shipping up to 155 million tonnes annually, is looking to make more incremental increases to output.

Critics, which include Ivan Glansenberg, the chief executive of rival Glencore, said a strategy of mining more iron ore has backfired and led to a dramatic fall in prices.

Western Australia state premier Colin Barnett has noted the impact on state royalties from the weaker market and urged Rio Tinto and BHP to rethink expansion strategies.

Both companies, however, have refused to slow expansion work. Rio Tinto Chief Executive Sam Walsh said iron ore mining was about “survival of the fittest”.

Iron ore <.IO62-CNI=SI> was last quoted at $70.60 per tonne. The steelmaking commodity fell to $68 a tonne last week, its weakest since June 2009.

The record for shipments to China was set at 32.03 million tonnes in August 2014, according to the port authority.

On July 1, the Port Hedland Port Authority amalgamated with the port of Dampier, creating what it says will be the world’s largest bulk export tonnage port.

BHP and Fortescue ship from Port Hedland. Dampier is one of two used by Rio Tinto. The other is Cape Lambert.