1. 197019711972197319741975197619771978197919801970 ARCO diversifies into coal. Core sampling showed Powder River Basin, in Wyoming, to be a strong resource ARCO SPS SPS decides to build an electric generation plant (Harrington Station) using coal vs. natural gas Powder River Basin Harrington Station

2. 197019711972197319741975197619771978197919801973 Powder River Basin Harrington StationARCO SPS Original Harrington Agreement $2.00 per ton

3. 197019711972197319741975197619771978197919801973 Original Harrington Agreement $2.00 per ton SPS ARCO SPS begins construction of Harrington Station Sierra Club Litigation begins

4. 197019711972197319741975197619771978197919801974 Original Harrington Agreement $2.00 per ton ARCO SPS SPS creates TUCO, a wholly owned subsidiary TUCO Sierra Club

5. 197019711972197319741975197619771978197919801974 ARCO and SPS/TUCO reopen negotiations regarding Harrington Agreement Original Harrington Agreement $2.00 per ton ARCO SPS TUCO Sierra Club

6. 19701971197219731974197519761977197819791980 Original Harrington Agreement $2.00 per ton ARCO SPS 1976 Revised Harrington Agreement $2.698 per ton State Agreement $6.50 per ton TUCO NEGOTIATIONS Sierra Club Injunction ends Sierra Club

7. 9.1%19701971197219731974197519761977197819791980 Original Harrington Agreement $2.00 per ton ARCO SPS Revised Harrington Agreement $2.698 per ton State Agreement $6.50 per ton 1977 5.8% Tolk Agreement $7.50 per ton TUCO Powder River Basin Harrington Station Tolk StationNEGOTIATIONS Sierra Club

8. 19701971197219731974197519761977197819791980 Original Harrington Agreement $2.00 per ton ARCO SPS Revised Harrington Agreement $2.698 per ton State Agreement $6.50 per ton 1977 Tolk Agreement $7.50 per ton ARCO starts delivering coal to TUCO under State agreementTUCO NEGOTIATIONS Sierra Club

9. 19701971197219731974197519761977197819791980 Original Harrington Agreement $2.00 per ton ARCO SPS TUCO Revised Harrington Agreement $2.698 per ton State Agreement $6.50 per ton 1980 Tolk Agreement $7.50 per ton TUCO (Cabot) STATE NEGOTIATIONS Sierra Club

10. 198019811982198319841985198619871988198919901982 TUCO (Cabot) ARCO Tolk Agreement $7.50 per ton ARCO starts delivering coal to TUCO under Tolk Agreement

11. 19801981198219831984198519861987198819891990 TUCO (Cabot) ARCO Tolk Agreement $7.50 per ton Letter of Agreement - Labor and Fringe Benefits adjusted by indices Letter of Agreement Labor & Fringe Benefits TOLK

12. 19801981198219831984198519861987198819891990 TUCO (Cabot) ARCO Tolk Agreement $7.50 per ton ARCO starts delivering coal to TUCO under Revised Harrington Agreement Letter of Agreement Labor & Fringe Benefits TOLK

13. 19801981198219831984198519861987198819891990 TUCO (Cabot) ARCO Tolk Agreement $7.50 per ton Letter of Agreement Labor & Fringe Benefits Tolk Second Amendment TOLK R. HAR.

14. 19801981198219831984198519861987198819891990 TUCO (Cabot) ARCO Tolk Agreement $7.50 per ton Letter of Agreement Labor & Fringe Benefits TOLK R. HAR. Performance under Revised Harrington and Tolk Agreements

15. 199019911992199319941995199619971998199920001994 TUCO (Cabot) ARCO TUCO sues ARCO- “Pricing Claims” Performance under Revised Harrington and Tolk Agreements

16. 19901991199219931994199519961997199819992000 TUCO (Cabot) ARCO 1997 Revised Harrington Agreement $2.698 per ton Revised Harrington Agreement ends TUCO sues ARCO Performance under Revised Harrington and Tolk Agreements

17. 19901991199219931994199519961997199819992000 TUCO (Cabot) ARCO Revised Harrington Agreement $2.698 per ton TOLK Performance under Tolk Agreements TUCO sues ARCO

18. 20002001200220032004200520062007200820092010 TUCO (Cabot) ARCO Performance under Tolk Agreements