Revisions in the law have not succeeded at helping patients get the compensation they deserve, said Huang Leping, director of the Beijing Yilian Legal Aid and Research Center of Labor, an NGO dedicated to providing free legal aid for workers.

In order to protect the interests of people with occupational diseases, China revised the prevention law, which went into effect at the end of 2011, with smoother channels for diagnosis and compensation.

"But the revised law did not work as expected, and our case load has not decreased in the past three years," Huang said.

He said the laws and regulations did not ease the difficulty for sufferers, and they were required to consume great amounts of time and energy.

In the July survey results, workers with pneumoconiosis spent about 17 months on average in lawsuits. Only 19 percent of the six million patients managed to get any compensation.

"Many of the workers found the pneumoconiosis after they quit their jobs, adding more problems and difficulties for them to get the deserved compensation," Huang said. Coals mines without insurance for workers or that don't have the resources to pay compensation are also major obstacles for sufferers.