#global-header .header-wrapper {
  // Prevent header resizing in IE8 and below
  @include ie-lte(8){
    width: 1020px;
  }
  @include ie-lte(6){
    width: 960px;
  }
}

#global-header .header-wrapper {
  // Prevent header resizing in IE8 and below
  @include ie-lte(8){
    width: 1020px;
  }
  @include ie-lte(6){
    width: 990px;
  }
}

Increase minimum width for header in IE6
Increase minimum width for header in IE6
