What is one type of centralized gas monitoring system used in underground mines?

A tube bundle system is a type of centralized gas monitoring system specifically designed for use in underground mines. This system consists of a series of tubes that are strategically placed throughout the mining environment to continuously sample the air for various gases. These samples are then analyzed for concentrations of hazardous gases such as methane, carbon monoxide, and oxygen levels.

The advantage of tube bundle systems lies in their ability to provide continuous monitoring over a wide area, allowing for real-time detection of changes in gas levels that could indicate dangerous conditions. This proactive approach enables mine operators to take timely safety measures to protect workers and ensure compliance with health and safety regulations.

In comparison to other options, while carbon cycle monitors and atmospheric pressure sensors may play a role in environmental monitoring, they don't serve the specific purpose of centralized gas monitoring like tube bundle systems do. GPS tracking systems also do not monitor gas levels; they are primarily used for tracking the location of equipment or personnel. Thus, tube bundle systems stand out as the correct answer for centralized gas monitoring in underground mining environments.