(Yicai Global) Nov. 21 -- Bitcoin prices have fallen to a level lower than the cost of production, making operations at many Chinese mining farms unviable.

The cryptocurrency fell 17 percent in less than 24 hours to hit USD4,300 yesterday afternoon, according to US exchange Coinbase.

The repeated declines mean that profits earned through mining are no longer enough to pay electricity and management charges. Chinese operations of older rigs such as the Antminer S and T9, as well as AvalonMiner 741 are no longer viable, according to data from one of the country's largest mining pool F2Pool, QQ News reported.

Some small and medium-sized mining farms located in China's Xinjiang, Inner Mongolia and other places have been wound up with rigs sold off following the fall.

Computing power supplier Suanlitou has canceled its contract with Antminer S9 as prices mean it is not able to pay power and management bills for Nov. 7 to Nov. 16. The ten consecutive days of loss-making mean that service contracts can be automatically terminated in line with contractual provisions.

Total computing power for Bitcoin mining has fallen by around 8 percent from its peak, which is an encouraging sign for miners and offers them hope, however. As a result, some miners that have wound up operations have started buying second-handed rigs.

"We can still earn a profit through hard work but the speed of making money has slowed," one miner said optimistically.