Coal mining in the Rhondda continued to expand throughout the early 20th century, although no further mines were sunk in Porth. The population continued to grow but conditions became hard after the Great Depression, and by the mid 1920s unemployment among mine workers rocketed. Matters worsened after the disastrous general strike of 1926 which saw many miners out of work for months. As mechanisation allowed other mining areas to become more profitable, the antiquated Rhondda mines sunk nearly 75 years earlier were unable to modernise and one-by-one began to close. Porth, like the rest of the Rhondda, was built solely around the coal industry, and with its collapse came mass unemployment, resulting in economic migration. There was a brief respite during the Second World War, when employment rose sharply. This was partially due for a need for Rhondda steam coal, but also due to large munition factories built in Bridgend, Hirwaun and Treforest to which the workers commuted. With the end of the war it was apparent that unemployment would return, but to ensure that the newly found factory skills gained during the previous six years were not lost the British Government passed the Distribution of Industry Act in 1945. This saw 25 new industry come to the Rhondda, six of them based in Porth. They ranged from Messrs. Jacob Beatus' box making company, a metal toy factory and a branch of Remploy aimed at disabled workers.