Sigma steps up on Major League Baseball project



The Sigma Group was retained by the Southeastern Wisconsin Professional Baseball Park Districts (SEWPBPD) to perform investigation of an abandon solid waste landfill located at the west end of Milwaukee’s Menomonee Valley. The purpose was to evaluate the subsurface conditions, determine the degree and extent of landfill gas generation, and produce a remedial strategy to develop the property for baseball stadium construction.

Sigma, in cooperation with the Wisconsin Department of Natural Resources (WDNR), devised an extensive monitoring network to evaluate the waste and determine the landfill methane gas generation and migration rate. Based on the waste evaluation and gas generation rates, Sigma identified effective remedial measures to address waste and control potential landfill gas migration into the proposed stadium structure.


Recommended methane control strategy for Miller Park implemented during stadium construction:

Services provided by Sigma included:

  • Removal of methane producing fill material beneath the stadium footprint.
  • Construction of a combination of clay barrier and passive methane venting system around the perimeter of the stadium to prevent lateral migration of methane from exterior areas entering stadium structure.
  • Interlocking the HVAC system to exhaust the atmosphere in event of methane detection.
  • Installation of subsurface methane detection system within the stadium at strategic locations.
  • Installation of methane detection sensors at strategic locations within structure and playing field.                                                                                                                                                                                                         The strategy was implemented, tested and considered appropriate to meet WDNR requirements and SEWPBPD objectives for the following reasons:
  • Proposed strategy eliminated potential for methane generation or accumulation within the structure and playing field footprint.
  • Any potential lateral migration of methane gas toward stadium building was effectively cut-off and vented to atmosphere.
  • Any potential lateral migration through utility corridors was cut-off by utility clay plugs and wall plugs installed within the utility construction and passively vented to atmosphere.