A 50-year male quaz quarry worker presents with progressive dyspnoea on exeion. Which of the following is the likely pneumoconiosis?

The major occupational exposures of free silica(SiO2)or crystalline quaz,include mining,stonecutting,employment in abrasive industries such as stone,clay,glass & cement manufacturing,foundry work,packing of silica flour,and quarrying paicularly of granite. Asbestosis is caused by exposure to asbestos-mining,processing,construction,ship repair.Berylliosis is caused by exposure to beryllium-processing alloys for high-tech industries.Exposure to organic dusts like cotton dust-milling,processing can produce byssinosis,which is an asthma-like syndrome. Ref:Harrison's medicine-18th edition,page no:2123