Fact check: After finishing building tunnels the drill is often left in the tunnel

1. Summary of the results

The statement about drills being left in tunnels is partially accurate but oversimplified. While most sources discuss tunnel boring techniques without addressing the fate of the equipment, there is concrete evidence that Tunnel Boring Machines (TBMs) have indeed been left in tunnels after construction, as demonstrated by the Channel Tunnel project where 11 TBMs were deliberately buried underground after completion ^[1].

2. Missing context/alternative viewpoints

The original statement lacks several crucial pieces of context:

• The practice is not universal but occurs for specific technical and economic reasons, including:
• Cost considerations for removal
• Transportation difficulties of massive machines
• Potential structural benefits to the tunnel itself ^[1]
• There's an important distinction between simple "drills" and Tunnel Boring Machines (TBMs), which are massive, sophisticated pieces of equipment ^[2]
• Modern tunneling involves complex processes including:
• Muck disposal
• Various tunneling techniques
• Rock recycling ^[3]
• Horizontal directional drilling ^[4]

3. Potential misinformation/bias in the original statement

The statement contains several problematic elements:

• It oversimplifies by using the term "drill" instead of the more accurate "Tunnel Boring Machine" ^[2]
• It implies this is a common practice when the only confirmed example in the sources is the Channel Tunnel ^[1]
• It omits the engineering rationale behind such decisions, potentially leading readers to assume it's done out of convenience rather than careful technical consideration ^[1]

The construction industry and engineering firms might benefit from this oversimplification as it could minimize public concern about the cost and complexity of major tunneling projects. However, it's important to understand that such decisions are made based on complex engineering and economic factors rather than convenience alone.