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                                                                  EXHIBIT 10.2.1

                      ASSIGNMENT AND ASSUMPTION AGREEMENT

     1.   For and in consideration of the payment by D. George Harris &
Associates, LLC, a Delaware limited liability company ("New DGHA") of one dollar
($1.00), D. George Harris & Associates, Inc., a Delaware corporation ("Old
DGHA") does hereby sell, assign and transfer to New DGHA all of its rights,
title and interest in, to and under the Amended and Restated Management Services
Agreement, dated as of October 6, 1998, among USS Holdings, Inc., a Delaware
Corporation ("Holdings"), Better Minerals & Aggregates Company (formerly USS
Intermediate Holdco, Inc. ("Holdco")), a Delaware corporation ("Better
Minerals"), U.S. Silica Company, a Delaware corporation ("Silica") and Old DGHA
(the "Management Agreement"). New DGHA hereby absolutely and irrevocably assumes
and is, and shall be, liable and solely responsible for any and all liabilities
and obligations of Old DGHA in, to and under to the Management Agreement.

     2.   For and in consideration of the payment by BMAC Holdings, Inc., a
Delaware corporation ("BMAC") of one dollar ($1.00), Better Minerals does hereby
sell, assign and transfer to BMAC all of its rights, title and interest in, to
and under the Management Agreement. BMAC hereby absolutely and irrevocably
assumes and is, and shall be, liable and solely responsible for any and all
liabilities and obligations of Better Minerals (as Holdco) in, to and under to
the Management Agreement.

     3.   For and in consideration of the payment by Better Minerals of one
dollar ($1.00), Silica does hereby sell, assign and transfer to Better Minerals
all of its rights, title and interest in, to and under the Management Agreement.
Better Minerals hereby absolutely and irrevocably assumes and is, and shall be,
liable and solely responsible for any and all liabilities and obligations of
Silica in, to and under to the Management Agreement.

     4.   Each party's signature below shall constitute such party's prior
written consent to all assignments and assumptions herein, pursuant to Section 9
of the Management Agreement.

     5.   This Assignment and Assumption Agreement shall be governed by and
construed in accordance with the laws of the State of New York, without regard
to its principles of conflicts of laws.

     IN WITNESS WHEREOF, the parties hereby have caused this Assignment and
Assumption Agreement to be executed as of this 30th day of September, 1999.

                              D. GEORGE HARRIS & ASSOCIATES, INC.

                              By: /s/
                                  ____________________________________
                                  Name:
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                           D. GEORGE HARRIS & ASSOCIATES, LLC

                           By: /s/
                              --------------------------------------
                              Name:

                           USS HOLDINGS, INC.

                           By: /s/
                              --------------------------------------
                              Name:

                           USS INTERMEDIATE HOLDCO, INC.

                           By: /s/ John A. Ulizio
                              --------------------------------------
                              Name:

                           U.S. SILICA COMPANY

                           By: /s/
                              --------------------------------------
                              Name:

                           BMAC HOLDINGS, INC.

                           By: /s/ John A. Ulizio
                              --------------------------------------
                              Name:

                           BETTER MINERALS & AGGREGATES COMPANY

                           By: /s/
                              --------------------------------------
                              Name:

                                       2<PAGE>

                                                                    EXHIBIT 10.3

                             TAX SHARING AGREEMENT
                             ---------------------

     AMENDED AND RESTATED AGREEMENT dated as of October 1, 1999 by and among USS
Holdings, Inc. ("USSH"), USS Intermediate Holdco, Inc. ("Holdco") and the other
                 ----                                    ------
signatories hereto (the "Subsidiaries").
                         ------------

     WHEREAS USSH, Holdco and certain of the Subsidiaries are parties to a Tax
Sharing Agreement dated February 9, 1996, as amended, and seek to further amend
such agreement; and

     WHEREAS, USSH is the common parent of an affiliated group of corporations
(an "Affiliated Group"), as defined in Section 1504(a) of the Internal Revenue
     ----------------
Code of 1986, as amended (the "Code"); and
                               ----

     WHEREAS, USSH will file a United States consolidated federal income tax
return (a "Consolidated Return") with members of the Affiliated Group of which
           -------------------
USSH is the common parent (the "USSH Consolidated Group"),
                                -----------------------

     NOW, THEREFORE, in consideration of the mutual covenants and promises
contained herein, the parties hereto agree as follows:

     1.  USSH shall file a Consolidated Return for each taxable period for which
this Agreement is in effect and for which the USSH Consolidated Group remains in
existence.

     2.  (a)  Subject to Section 4, Holdco shall pay to USSH with respect to
each taxable year during which Holdco is a member of the USSH Consolidated Group
an amount equal to the Holdco Tax Amount for such year.

         (b)  The term "Holdco Tax Amount" shall mean an amount equal to the
                        -----------------
federal income tax liability that Holdco would have incurred for a taxable year
had Holdco filed a Consolidated Return that included (i) Holdco as common parent
and (ii) those of Holdco's subsidiaries that would be members of an Affiliated
Group having Holdco as the common parent (the "Holdco Subgroup"). For purposes
                                               ---------------
of computing the Holdco Tax Amount for a taxable year, the Holdco Subgroup shall
take into account all items of gain, income, deductions, losses, credits,
carryovers of losses and credits (including the credit calculated under Code
Section 53, if any) from prior taxable years (taking into account any actual
federal income tax returns (whether separate returns or Consolidated Returns)
filed by members of the Holdco Subgroup for a prior taxable year of such
member), and all other tax attributes of the Holdco Subgroup, which attributes
may be subject to limitations under the Code and applicable Treasury
Regulations, that would have been taken into account had the Holdco Subgroup
actually filed a Consolidated Return. Without limiting the generality of the
foregoing, computation of the Holdco Tax Amount for any taxable year shall take
into account and compensate the Holdco Subgroup for
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any deductions, losses, credits and carryovers of losses and credits generated
by it (and that were utilized by the USSH Consolidated Group) at the time such
deductions, losses or credits could have been used by the Holdco Subgroup to
reduce its federal income tax liability (had the Holdco Subgroup actually filed
a Consolidated Return).

               (c) For purposes of this Agreement, "federal income tax" shall
include, but not be limited to, all federal taxes on income (including any tax
imposed under Code Section 55) and any applicable interest, penalties or
additions to tax.

          3.   If the Holdco Tax Amount for a taxable year is adjusted after the
initial Consolidated Return of the USSH Consolidated Group has been filed
(whether as a result of an amended return, a claim for refund, an audit by the
Internal Revenue Service ("IRS"), or otherwise), then the amounts calculated
under Section 2(a) shall be recomputed to reflect such adjustments.  Subject to
Section 4, Holdco shall make a payment of any resulting additional federal
income tax to USSH or USSH shall make a payment of any resulting federal income
tax refund to Holdco.

          4.   USSH shall make the computations under Section 2 and 3 in a
reasonable manner. With respect to computations under Section 2, estimated
federal income tax payments by Holdco shall be made no later than three (3)
business days prior to the time USSH is required to make estimated federal
income tax payments to the IRS, and final settlements for a taxable year shall
be made between USSH and Holdco no later than three (3) business days prior to
the filing of the Consolidated Return of the USSH Consolidated Group for such
taxable year. With respect to computations under Section 3, payments determined
to be due to USSH or Holdco shall be paid within fifteen (15) business days
after the relevant federal income tax return (or amended return) or other
document reflecting such adjustment is filed or executed; provided that, in no
                                                          -------------
event shall USSH be required to make any actual payment to Holdco with respect
to a refund until USSH actually receives such refund (or actually receives the
benefit of such a refund through the use of a credit or otherwise), and provided
                                                                        --------
further that, if the Holdco Subgroup for any taxable year has a loss or credit
------------
which could be carried back to and which would reduce the Holdco Tax Amount (as
adjusted) for any earlier taxable year for which the Holdco Subgroup was
included in the USSH Consolidated Group, then USSH shall pay to Holdco on the
date the USSH Consolidated Group Consolidated Return is actually filed for such
taxable year the amount by which the Holdco Tax Amount in such earlier taxable
year is reduced by reason of such carryback (or, to the extent that USSH must
file a claim for refund to recoup such amount, the date that USSH actually
receives such refund (or actually receives the benefit of such a refund through
the use of a credit or otherwise)).

          5.   The principles of this Agreement shall also apply to any
consolidated, combined or unitary state or local income tax return that includes
USSH and Holdco (or one or more of the members of the Holdco Subgroup).

          6.   This Agreement shall fix the liability between USSH and Holdco as
to the matters covered herein, notwithstanding that (i) the Agreement or any
part thereof is not controlling for federal income tax or other purposes,
including, but not limited to, the computation of earnings and profits for
federal income tax purposes, or (ii) USSH and

                                       2
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corporations (other than Holdco Subgroup members) which are now or may become
members of the USSH Consolidated Group may enter into different agreements for
the allocation of consolidated federal income tax liability to such other
corporations.

          7.   This Agreement shall apply to the taxable year of the USSH
Consolidated Group ending in 1996 and all subsequent taxable years during which
members of the Holdco Subgroup, as it may exist from time to time, are members
of the USSH Consolidated Group. This Agreement shall supersede any tax sharing
agreements or arrangements with respect to USSH, Holdco or any Subsidiary, and
each of USSH, Holdco, and the Subsidiaries agree that each such agreement shall
be terminated hereby and be of no further force and effect.

          8.   (a) This Agreement shall be binding upon and inure to the benefit
of any successors or assigns of any of the parties hereto, to the same extent as
if the successor had been an original party to the Agreement.

               (b) No amendment, supplement, modification or waiver of this
Agreement shall be binding unless executed in writing by the party to be bound
thereby. No waiver of any of the provisions of this Agreement shall be deemed or
shall constitute a waiver of any other provision hereof (whether or not
similar), nor shall such waiver constitute a continuing waiver unless otherwise
expressly provided.

               (c) Any alteration, modification, addition, deletion, or other
change in the consolidated federal income tax return provisions of the Code or
the Treasury Regulations thereunder shall automatically be applicable to this
Agreement mutatis mutandis.
          ------- --------

               (d) In the event that any one or more of the provisions contained
in this Agreement shall, for any reason, be held to be invalid, illegal or
unenforceable in any respect, the validity, legality and enforceability of any
such provision in every other respect and the remaining provisions of this
Agreement shall not be in any way impaired.

               (e) This Agreement may be executed in one or more counterparts.
Each person that becomes a member of the Holdco Subgroup after the date hereof
shall become a party hereto by executing a counterpart hereof and delivering the
same to USSH. Each such counterpart shall be deemed an original, but all
counterparts together shall constitute one and the same instrument.

               (f) This Agreement shall be governed by the laws of the State of
New York.

                                       3
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          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed by their duly authorized representatives as of the date first
written above.

                                         USS HOLDINGS, INC.

                                         By:  /s/ Richard J. Nick
                                            ---------------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         BMAC HOLDINGS, INC.

                                         By:  /s/ Richard J. Nick
                                            ---------------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         BETTER MINERALS & AGGREGATES COMPANY

                                         By:  /s/ Richard J. Nick
                                            ---------------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         U.S. SILICA COMPANY

                                         By:  /s/ Richard J. Nick
                                            ---------------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         THE FULTON LAND AND TIMBER COMPANY

                                         By:  /s/ Richard J. Nick
                                            ---------------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

<PAGE>

                                         OTTAWA SILICA COMPANY

                                         By:  /s/ John A. Ulizio
                                            --------------------------------
                                           Name:  John A. Ulizio
                                           Title: Secretary

                                         PENNSYLVANIA GLASS SAND CORPORATION

                                         By:  /s/ Richard J. Nick
                                            --------------------------------
                                           Name:  Richard J. Nick
                                           Title: Treasurer

                                         BETTER MATERIALS CORPORATION

                                         By:  /s/ Richard J. Nick
                                            --------------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         BMC TRUCKING, INC.

                                         By:  /s/ Richard J. Nick
                                            --------------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         BUCKS COUNTY CRUSHED STONE COMPANY

                                         By:  /s/ Richard J. Nick
                                            --------------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President
<PAGE>

                                         CHIPPEWA FARMS CORPORATION

                                         By:  /s/ Richard J. Nick
                                            -------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         SHORE STONE COMPANY, INC.

                                         By:  /s/ Richard J. Nick
                                            -------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         GEORGE F. PETTINOS, INC.

                                         By:  /s/ Richard J. Nick
                                            -------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         ELLEN JAY, INC.

                                         By:  /s/ Richard J. Nick
                                            -------------------------
                                           Name:  Richard J. Nick
                                           Title: Vice President

                                         COMMERCIAL STONE CO., INC.

                                         By:  /s/ Richard J. Nick
                                            -------------------------
                                           Name:  Richard J. Nick
                                           Title: Assistant Secretary

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