Here is a brute force method, not a speed demon but it is reliable if you let it sit and cook
With a reference to the "Microsoft Scripting Runtime"
Public Sub BruteForceTriangles()
Dim txtstream As TextStream
Dim fso As New FileSystemObject
Dim face As Acad3DFace
Dim myfile As String
Dim acent As AcadEntity
On Error GoTo MyExit
myfile = "C:\GDrive\AutoCAD\HLB-Lime.txt"
Set txtstream = fso.OpenTextFile(myfile, ForWriting, True)
For Each acent In ThisDrawing.ModelSpace
If acent.ObjectName = "AcDbFace" Then
Set face = acent
If face.Layer = "0-HLB-LimeArea" Then
txtstream.WriteLine face.Coordinates(0) & "," & face.Coordinates(1) & "," & face.Coordinates(2) & "," & face.Coordinates(3) & "," & face.Coordinates(4) & "," & face.Coordinates(5) & "," & face.Coordinates(6) & "," & face.Coordinates(7) & "," & face.Coordinates(8)
End If
End If
Next acent
MyExit:
txtstream.Close
End Sub