Michael Conner
Michael is one of Drill Tech’s General Superintendents with nearly 30 years’ experience in construction, 19 years of which have been in the supervision of tunnel operations. He is OSHA Certified for Tunnel Safety and Gas Testing, ensuring the best practices are in place among Drill Tech crew and equipment. Mr. Conner’s tunneling specialization has included rehabilitation, new construction, and emergency projects throughout the United States—where he has encountered a variety of ground conditions that require expert adaptability.
Michael's Featured Projects
Upper Llagas Creek Phase 2A | Morgan Hill, CA
Superintendent
Drill Tech constructed this 15' diameter 2,200' SEM tunnel through Morgan Hill’s Franciscan formation and variable ground conditions as part of a creek flood stormwater diversion. The tunnel was excavated with roadheader and drill/blast methods, with Drill Tech-designed initial support that included steel beam sets with infill shotcrete, and systematic rock bolts with shotcrete. Drill Tech also designed the 8,700 sqft of temporary shoring and perimeter sound wall for this project. Canopy tubes were installed from both portals and in the tunnel’s transition zone, as Drill Tech’s value engineered tunnel extension included low cover SEM methods of canopy tubes and compartmentalized excavation techniques.
NAVFAC Navy RR Culverts Ph. 1 | Shelton, WA
Superintendent
The purpose of this project is to replace two existing culverts under an active rail line with fish passage culvert tunnels. The project included two horseshoe shaped tunnels with overall lengths of 160' and 235'. The 20' wide by 15' tall tunnels were supported using liner plate with internal steel sets, including invert struts and a full width concrete invert. Tunnel excavation was completed using mechanical methods in alluvium type soils, utilizing grouted canopy tubes for pre-excavation support ahead of excavation. The final condition included a partial liner of reinforced shotcrete as scour protection for stream flow.
Third St. Light Rail Program Ph. 2 Central Subway Receiving Shaft and Cross Passages | San Francisco, CA
Superintendent
This $1.9 billion DBB project encompasses two contracts connecting the South of Market area with Chinatown for SFMTA. The project generally included twin TBM tunnels, five stations, and ancillary system upgrades. The tunnels were 1.7 miles long and stations several hundred feet deep depending on the location. Drill Tech scopes consisted of a 50' x 50' x 50' inside dimension receiving shaft for retrieval of twin TBMs. The shaft consisted of soldier piles and three levels of walers and struts, with the soldier piles being set into 74' deep CSM panels keyed into Franciscan bedrock. Outside of the shaft, compensation grouting was used to protect the surrounding buildings from settlement when the TBMs passed into the shaft.
Anderson Dam Tunnel Project | Morgan Hill, CA
Superintendent
This retrofit project established new water supply tunnels, drop shafts, and supporting structures for future reconstruction of Anderson Dam. Drill Tech performed 1,600' of SEM tunneling with diameters ranging from 19' to 24' through the Santa Clara and Franciscan formations of Morgan Hill. Portal shoring was comprised of 120’ deep soil nails and 12” thick reinforced shotcrete. The shaft and ground support were designed by Drill Tech, and incorporated value engineering that included canopy tubes in the transition zone for a stronger tunnel lining to minimize risks and ensure long-term stability of the tunnel.
