(a) The tax lien on each unredeemed tract or lot, or each unredeemed part thereof or undivided interest therein shall be sold by the sheriff, in the same order as set forth in the list and notice prescribed in section two of this article, at public auction to the highest bidder, between the hours of nine in the morning and four in the afternoon on any business working day after October 14, and before the twenty-third day of November: Provided, That no tax lien for such unredeemed tract or lot or undivided interest therein shall be sold upon any bid or for any sum less than the total amount of taxes, interest and charges then due: Provided, however, That at any such sale, the tax lien for each unredeemed tract or lot, or undivided interest therein, shall be offered for sale and sold for the entirety of such tract or lot or undivided interest therein as the same is described and constituted as a unit or entity in the list and notice prescribed in section two of this article. If the sale shall not be completed on the day designated in the notice for the holding of such sale, it shall be continued from day to day between the same hours until disposition shall have been made of all the land. The payment for any tax lien purchased at a sale shall be made by check or money order payable to the sheriff of the county and delivered before the close of business on the day of the sale.

(b) Each sheriff is immune from liability if a loss or claim results from the sale of a tax lien conducted pursuant to the provisions of this article or from any subsequent conveyance of the property to which the lien attaches: Provided, That where a sheriff fails or refuses to sell said tax lien pursuant to the provisions of this article for reasons other than those provided by section seven of this article, the sheriff may be compelled by mandamus to sell the same upon the petition of the Auditor or any taxpayer of the county in a court of competent jurisdiction.