Complex sentence: Only the upper part of the shaft is accessible; the rest is filled with rubble, and nothing is known about the tomb's layout, although the tomb was excavated by Victor Loret in 1899, no report was published.
Split into simpler sentences: Only the upper part of the shaft is accessible; the rest is filled with rubble, and nothing is known about the tomb's layout. Although the tomb was excavated by Victor Loret in 1899, no report was published.