actually mr. fongi, i hope you might be able to answer some of them. the contention has been raised that the tunnel-boring machine should be left in chinatown underground and i'm wondering if you could address what has often been raised with that particular contention. >> chairman wiener, supervisor john fongi. the concept of actually leaving the machines in the ground were analyzed early on in 2006 and incorporated as part of the original environmental analysis. it was called alternative 3a that was rejected as part of the original environmental analysis and that being said, that option was looked at at the end of last year, and brought to our policy board to reconsider that option. and that option was not selected. >> the soil conditions have been thoroughly analyzed and similar to the soil conditions that we're facing along the corridor, that is currently under construction. the sfmta is employing tried and trued engineering construction techniques that are currently being performed along the alignment and currently being performed successfully by t