Two workers operating? / measuring? a revolving cylinder (lathe?), National Colliery, Porth. A man, standing this side of the machine, wears overalls and a flat cap and places his right hand by the cylinder. A middle-aged man, on the other side of the machine, places callipers? onto the cylinder with his right hand. The machine has hoses, wheels, levers, on / off buttons and a large revolving cylinder. Around the machine is a brush, pipes, a mug, twisted metal shavings and a brick wall with two leaded windows. Lower margin of image does not extend to lower margin of paper. Black and white image with a range of tones. Text on image, chalked on plank, 'NO ENT[RY]'