What is the required scale for maps of coal mines?

The correct answer is based on established guidelines for mapping coal mines, which are crucial for both safety and operational purposes. The requirement for a scale of not less than 100ft and not more than 500ft to the inch ensures that the maps provide a detailed yet manageable representation of the mine's layout.

This scale allows for enough detail to be visible, aiding in navigation and planning within the mine, while also being practical for printing and usage in the field. A wider scale range like this accommodates various needs, ensuring that users can glean crucial information without becoming overwhelmed by excessive detail in the map. The specifications help ensure compliance with safety regulations and operational standards, which are essential for preventing accidents and facilitating efficient mining operations.

The other options suggest scales that either provide too little detail for safe navigation or overly compact the information, making it difficult to read and interpret maps effectively. Keeping the scale within the defined parameters strikes a balance between clarity and usability, making option B the most suitable choice.