-4 Vesting Notwithstanding anything in [Section 4.2] to the contrary, [Schedule D.2] Participants shall be vested in their Retirement Contribution Accounts upon completing three years of Vesting Service. For this purpose, a “Year of Vesting Service” means a Plan Year in which the [Schedule D.2] Participant is credited with at least 1,000 Hours of Service. Service with a [Schedule D.2] Employer and Affiliates shall be recognized for purposes of this [Section D.2-4]4], including, but not limited to, service that occurred prior to the Effective Date, applying these rules as if the [Schedule D.2]

-4 Vesting Notwithstanding anything in [Section 4.2] to the contrary, [Schedule D.2]4] Participants shall be vested in their Retirement Contribution Accounts upon completing three years of Vesting Service. For this purpose, a “Year of Vesting Service” means a Plan Year in which the [Schedule D.2]4] Participant is credited with at least 1,000 Hours of Service. Service with a [Schedule D.2] EmployerHC and Affiliates shall be recognized for purposes of this [Section D.2-4-4]4], including, but not limited to, service that occurred prior to the Effective Date, applying these rules as if HC and its affiliates at that time were Affiliates under the Plan. Notwithstanding the foregoing, a [Schedule D.2]4] Participant shall be fully vested in his or her Retirement Contribution Account upon death, Disability, or attaining Normal Retirement Age.

-4 Vesting Notwithstanding anything in [Section 4.2] to the contrary, [Schedule D.2]1] Participants shall be vested in their Retirement Contribution Accounts upon completing three years of Vesting Service. For this purpose, a “Year of Vesting Service” means a Plan Year in which the [Schedule D.2]1] Participant is credited with at least 1,000 Hours of Service. Service with a [Schedule D.2] EmployerKnife River Corporation and Affiliates shall be recognized for purposes of this [Section D.2-1-4]4], including, but not limited to, service that occurred prior to the Effective Date, applying these rules as if Knife River Corporation and its affiliates at that time were Affiliates under the Plan. Notwithstanding the foregoing, a [Schedule D.2]1] Participant shall be fully vested in his or her Retirement Contribution Account upon death, Disability, or attaining Normal Retirement Age.

-4 Vesting Notwithstanding anything in [Section 4.2] to the contrary, [Schedule D.2]3] Participants shall be vested in their Retirement Contribution Accounts upon completing three years of Vesting Service.Service; provided, however that [Schedule D.3] Participants who were employed by Star Aggregates, Inc. on ​, shall be fully vested. For this purpose, a “Year of Vesting Service” means a Plan Year in which the [Schedule D.2]3] Participant is credited with at least 1,000 Hours of Service. Service with a [Schedule D.2] EmployerJTL and Affiliates shall be recognized for purposes of this [Section D.2-3-4]4], including, but not limited to, service that occurred prior to the Effective Date, applying these rules as if JTL and its affiliates at that time were Affiliates under the Plan. Notwithstanding the foregoing, a [Schedule D.2]3] Participant shall be fully vested in his or her Retirement Contribution Account upon death, Disability, or attaining Normal Retirement Age.