Back in the days of early mines, there weren't any wreckers or trucks to pull coal to the surface. Animals were in charge of this job. The strength they had was surprising; animals like donkeys could carry several times their own weight. Animals used for pulling coal carts to the surface depended on the geography of each mining camp and also on the region of the world. Here's a list of the most commonly used animals to pull coal carts in early mines.
Ponies were used in early British mines to pull coal carts to the surface. They also were used in other types of mining. Miners took advantage of their strength and they rarely resisted. Ponies didn't usually live long because of the extremely harsh conditions they suffered. They were assigned heavy duties that generally injured them. According to the BBC, the use of ponies was implemented when children and women stopped working in early coal mines.
Donkeys were easily the most used animal in early mines to pull coal carts to the surface. They're one of the most resistant animals in the natural world. They always walk with a slow pace but never fail to deliver. They also transported equipment and tools. Donkeys were used in coal mines in different parts of the world, such as the United States, India and the Middle East.
Back in the 13th and 14th centuries, groups of goats were used to pull coal to the surface. This happened in England coal mines and their use was later extended to the rest of Europe. Goats couldn't carry too much weight, but when a group of two or three goats worked together, they could pull any coal cart. As with the ponies, the tough conditions also affected goats, even causing injury.
Canaries were used in early coal mines. Although they didn't pull carts to the surface, they did "announce" when carts should be pulled. They were used as living sensors for toxic gases, such as methane and carbon monoxide. Early mining didn't have appropriate ventilation, so using the canary was a good way of determining the toxicity of the air. If the canary stopped singing or fell, it meant that the toxicity was too dangerous to remain inside the mine. When this happened, miners knew that they had to leave the mine and head up to the surface with all the coal collected at that moment.