Four-ton grab buckets operating on the four bridge-tramways pick up the coal from the hold of lake steamers and deposit it either on the dock or in cars. The four machines can be moved to any part of the dock to which steamers are moored and four ships can be unloaded rapidly at one time. The motive power is electricity.
Courtesy of the J. M. Dodge Co.
Storing Coal
A 480,000-ton anthracite coal storage plant. Coal cars are dumped into hoppers under the tracks and the coal carried to the top of the piles by conveyors. It is reloaded into cars by other conveyors operating at the base of each pile. This system has been of great value in preventing a shortage of coal during strikes.
Consequently a plan has been evolved for the ventilating current to be reversed periodically, in order to remove dust which has settled on the side of timbering and crevices, and the roadways to be watered in order to allay the dust. A plan has also been tried of spreading fine stone-dust in the roadways. This mixes with the coal-dust and renders it less inflammable.
Unfortunately the disastrous effects of an explosion do not end with the explosion itself. The main products of combustion, whether of fire-damp or coal-dust, are carbon monoxide and carbon dioxide. The latter causes suffocation and the former is a dangerous poison. It is the dreaded “after-damp” of the miner. Those who survive an explosion are therefore in danger of suffocation or poisoning, and it becomes imperative to restore the circulation of the air with the least possible delay. For even if the fan has escaped injury, fallen portions of the roof may have choked up some of the roadways, or the explosion may have torn down doorways and provided a short cut for the air. But if the atmosphere is dangerous for men in the pit at the time, it is equally dangerous for others to go down and effect repairs or render first aid.
The work of the rescue party is therefore a labor of desperate heroism and often attended by additional loss of life. It has recently been found possible to reduce the dangers of after-damp by providing rescue parties with respirators fitting over the mouth and nose, and supplied with oxygen from two steel bottles of the compressed gas strapped across the back. An effective apparatus of this kind, such as has been adopted by the United States Government for the use of the Bureau of Mines Rescue Crew, is shown in the accompanying [illustration]. The bag in front is known as a “breathing bag” and has separate compartments for the inhaling and exhaling, the tube at the right leading to the former and that at the left to the exhaling compartment, which usually contains sticks of caustic soda to absorb the carbon dioxide exhaled by the wearer.