When China offers to build projects overseas, do they use local labour or they bring in workers from China?

I'm asking because what first seems like a great donation from China can turn out a little differently if they bring in Chinese labour.

If China decides to "donate" a building overseas and make the local people work, this contributes to the development of that country. The workers pay taxes, acquire knowledge and so forth. If China brings in Chinese labour, they the contribute almost nothing to that country. Sure, they get a shiny new building, but what did it really give to that country? What is the economic impact? Nothing much.

Dear Mr JF, infrastructure projects (if useful, properly planned and properly implemented)once completed, can help a country a big deal. That should be the number 1 benefit to a nation. In terms of labour, I think Mr JF, is not particularly familiar with what infrastructure projects are like. Infrastructure projects are BIG projects, that involve not only the people building the structure (it is not like building a condo...), but the whole community around the area where the infrastructure is going to be. Contractors (in this case the Chinese) need local sub-contractors to provide a huge range of logistical support. Materials, food etc. are bought locally or from neighboring areas. All this activity strongly stimulates and improves the local economy of a given area. So, in practice, it doesn't really matter if the Chinese are going to take along all of their labour from China. Potentially, the benefits to the site and the nation where tha infrastructure is going to be built are enormous anyway, because of the trade and jobs opportunities created all around it.