i: Integer;

This example copies all horizontal page breaks from first sheet to second

Workbook.Sheets[

var
   i: Integer;
begin

  for i := 1 to Workbook.Sheets[1].HPageBreaks.Count do
  begin
    Workbook.Sheets[2].HPageBreaks.Add(Workbook.Sheets[1].HPageBreaks.Item[i].Location);
  end;
end;