Student or Learner
I'd like to have a clear explanation about the word in bold in the following sentence which is an extract from a technical revue. Here is it:
"What's more, areas of a mine where mining is finished and have been sealed off, but which still contain significant amounts of coal, coal dust, and methane, are often not monitored directly.
I am always a bit stuck whith this kind of contraction ('s) what does it mean ? It is 'what is'.
Thanks in advance for your help.