SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 -------------

                                   FORM 11-K

                                 ANNUAL REPORT
                        PURSUANT TO SECTION 15(d) OF THE
                        SECURITIES EXCHANGE ACT OF 1934

[X]   ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT
      OF 1934

For the fiscal year ended December 31, 1998.


                                       OR


[ ]   TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE
      ACT OF 1934

For the transition period from _____ to _____.

Commission file number 1-13105.


A.    Full title of the plan and the address of the plan, if different from
      that of the issuer named below:  Arch Coal, Inc. Employee Thrift Plan.

B.    Name of issuer of the securities to be held pursuant to the plan and the
      address of its principal executive office:  Arch Coal, Inc., Suite 300,
      CityPlace One, St. Louis, Missouri  63141.


FINANCIAL STATEMENTS AND EXHIBITS Financial Statements and Schedules Independent Auditors' Reports Statements of Net Assets Available for Benefits, With Fund Information Statement of Changes in Net Assets Available for Benefits, With Fund Information Notes to Financial Statements Schedule of Assets Held for Investment Purposes Schedule of Reportable Transactions Exhibits 23.1 - Consent of Ernst & Young LLP, Independent Auditors 23.2 - Consent of Stone Carlie & Company, L.L.C., Independent Auditors

Arch Coal, Inc. Employee Thrift Plan St. Louis, Missouri Financial Statements With Supplemental Schedules and Independent Auditors' Reports Year Ended December 31, 1998

CONTENTS PAGE Independent Auditors' Reports...........................1-2 Financial Statements Statements of Net Assets Available for Benefits, With Fund Information.................................3-6 Statement of changes in Net Assets Available for Benefits, With Fund Information.......................7-10 Notes to Financial Statements...........................11-21 Supplemental Schedules Schedule of Assets Held for Investment Purposes.........22-23 Schedule of Reportable Transactions.....................24-25

INDEPENDENT AUDITORS' REPORT To the Administrator Arch Coal, Inc. Employee Thrift Plan We have audited the accompanying statement of net assets available for benefits of the Arch Coal, Inc. Employee Thrift Plan as of December 31, 1998 and the related statement of changes in net assets available for benefits for the year then ended. These financial statements are the responsibility of the Plan's management. Our responsibility is to express an opinion on these financial statements based on our audit. We conducted our audit in accordance with generally accepted auditing standards. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion. In our opinion, the financial statements referred to above present fairly, in all material respects, the net assets available for benefits of the Plan at December 31, 1998, and the changes in net assets available for benefits for the year then ended in conformity with generally accepted accounting principles. Our audit was conducted for the purpose of forming an opinion on the basic financial statements taken as a whole. The accompanying supplemental schedules of assets held for investment purposes as of December 31, 1998 and reportable transactions for the year then ended are presented for purposes of complying with the Department of Labor's Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974, and are not a required part of the basic financial statements. The fund information in the statement of net assets available for benefits and the statement of changes in net assets available for benefits is presented for purposes of additional analysis rather than to present the net assets available for benefits and the changes in net assets available for benefits of each fund. The supplemental schedules and fund information have been subjected to the auditing procedures applied in our audit of the basic financial statements and, in our opinion, are fairly stated in all material respects in relation to the basic financial statements taken as a whole. STONE CARLIE & COMPANY, L.L.C. ST. LOUIS, MISSOURI June 25, 1999

Report of Independent Auditors To the Administrator Arch Coal, Inc. Employee Thrift Plan We have audited the accompanying statement of net assets available for benefits, with fund information of the Arch Coal, Inc. Employee Thrift Plan as of December 31, 1997. This financial statement is the responsibility of the Plan's management. Our responsibility is to express an opinion on this financial statement based on our audit. We conducted our audit in accordance with generally accepted auditing standards. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statement is free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statement. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion. In our opinion, the financial statement referred to above presents fairly, in all material respects, the net assets available for benefits of the Plan at December 31, 1997, in conformity with generally accepted accounting principles. The fund information in the statement of net assets available for benefits is presented for purposes of additional analysis rather than to present the net assets available for benefits of each fund. The fund information has been subjected to the auditing procedures applied in our audit of the basic financial statement and, in our opinion, is fairly stated in all material respects in relation to the basic financial statement taken as a whole. Louisville, Kentucky Ernst & Young LLP June 25, 1998

ARCH COAL, INC. EMPLOYEE THRIFT PLAN STATEMENT OF NET ASSETS AVAILABLE FOR BENEFITS, WITH FUND INFORMATION December 31, 1998 Barclays Twentieth Arch Coal, ARCO S&P 500 Primco Twentieth Century Inc. Common Common Equity Index Stable Value Century International Total Stock Fund Stock Fund Fund Fund Ultra Fund Growth Fund ------------ ----------- ----------- ----------- ----------- ----------- ----------- Assets Investments Common stock $ 24,770,870 $ 2,787,504 $20,123,472 - - - - Mutual funds 103,913,242 - - - - $21,471,454 $6,214,873 Pooled separate account 21,601,010 - - - $21,601,010 - - Investment contracts 19,955,691 - - - 19,955,691 - - Collective trust 24,096,444 - - $20,826,732 3,269,712 - - Participant notes receivable 10,340,684 - - - - - - ------------ ----------- ----------- ----------- ----------- ----------- ---------- Total investments 204,677,941 2,787,504 20,123,472 20,826,732 44,826,413 21,471,454 6,214,873 ------------ ----------- ----------- ----------- ----------- ----------- ---------- Receivables Participant 536,310 13,307 - 66,216 92,435 83,162 25,103 Employer 278,765 6,989 - 32,003 54,606 41,863 13,333 ------------ ----------- ----------- ----------- ----------- ----------- ---------- Total receivables 815,075 20,296 - 98,219 147,041 125,025 38,436 ------------ ----------- ----------- ----------- ----------- ----------- ---------- Net assets available for benefits $205,493,016 $ 2,807,800 $20,123,472 $20,924,951 $44,973,454 $21,596,479 $6,253,309 ============ =========== =========== =========== =========== =========== ========== The accompanying notes are an integral part of these financial statements. Page 3

ARCH COAL, INC. EMPLOYEE THRIFT PLAN STATEMENT OF NET ASSETS AVAILABLE FOR BENEFITS, WITH FUND INFORMATION (Continued) December 31, 1998 American Schwab Benham Century Franklin MAS Value J.P. Morgan Dodge & Cox Personal GNMA Income and Balance Institutional Diversified Balanced Choice Loan Fund Growth Fund Sheet Fund Fund Fund Fund Account Fund Fund ------------ ------------- ------------ ------------ ----------- ----------- ----------- ----------- Assets Investments Common stock - - - - - - $1,859,894 - Mutual funds $ 8,171,106 $30,049,366 $ 7,610,710 $10,861,857 $ 6,634,479 $12,899,397 - - Pooled separate account - - - - - - - - Investment contracts - - - - - - - - Collective trust - - - - - - - - Participant notes receivable - - - - - - - $10,340,684 ------------ ----------- ----------- ----------- ----------- ----------- ---------- ----------- Total investments 8,171,106 30,049,366 7,610,710 10,861,857 6,634,479 12,899,397 1,859,894 10,340,684 ------------ ----------- ----------- ----------- ----------- ----------- ---------- ----------- Receivables Participant 18,246 103,771 28,320 40,240 23,389 42,121 - - Employer 9,531 51,650 13,922 21,325 11,422 22,121 - - ------------ ----------- ----------- ----------- ----------- ----------- ---------- ----------- Total receivables 27,777 155,421 42,242 61,565 34,811 64,242 - - ------------ ----------- ----------- ----------- ----------- ----------- ---------- ----------- Net assets available for benefits $ 8,198,883 $30,204,787 $ 7,652,952 $10,923,422 $ 6,669,290 $12,963,639 $1,859,894 $10,340,684 ============ =========== =========== =========== =========== =========== ========== =========== The accompanying notes are an integral part of these financial statements. Page 4

ARCH COAL, INC. EMPLOYEE THRIFT PLAN STATEMENT OF NET ASSETS AVAILABLE FOR BENEFITS, WITH FUND INFORMATION December 31, 1997 INVESCO INVESCO INVESCO Arch Coal, Intermediate Select INVESCO Total Inc. Common Government Income High Yield Return Total Stock Fund Bond Fund Fund Bond Fund Fund ----------- ----------- ----------- ----------- ----------- ----------- Assets Investments Common stock $ 91,195 $ 91,195 - - - - Mutual funds 68,685,454 - $ 8,091,573 $ 7,346,224 $ 2,904,865 $19,123,491 Pooled separate account 2,020,411 - - - - - Investment contracts 6,007,769 - - - - - Collective trust 13,820,591 - - - - - Participant notes receivable 4,786,256 - - - - - ----------- ----------- ----------- ----------- ----------- ----------- Total investments 95,411,676 91,195 8,091,573 7,346,224 2,904,865 19,123,491 ----------- ----------- ----------- ----------- ----------- ----------- Cash 126,492 - - - - - ----------- ----------- ----------- ----------- ----------- ----------- Net assets available for benefits $95,538,168 $ 91,195 $ 8,091,573 $ 7,346,224 $ 2,904,865 $19,123,491 =========== =========== =========== =========== =========== =========== The accompanying notes are an integral part of these financial statements. Page 5

ARCH COAL, INC. EMPLOYEE THRIFT PLAN STATEMENT OF NET ASSETS AVAILABLE FOR BENEFITS, WITH FUND INFORMATION (Continued) December 31, 1997 INVESCO INVESCO INVESCO Industrial INVESCO International Emerging Capital Income Dynamics Growth Growth Preservation Loan Fund Fund Fund Fund Fund Fund ----------- ----------- ----------- ----------- ----------- ----------- Assets Investments Common stock - - - - - - Mutual funds $13,716,282 $11,694,364 $ 1,727,160 $ 3,458,050 $ 623,445 - Pooled separate account - - - - 2,020,411 - Investment contracts - - - - 6,007,769 - Collective trust - - - - 13,820,591 - Participant notes receivable - - - - - $ 4,786,256 ----------- ----------- ----------- ----------- ----------- ----------- Total investments 13,716,282 11,694,364 1,727,160 3,458,050 22,472,216 4,786,256 ----------- ----------- ----------- ----------- ----------- ----------- Cash - - - - 126,492 - ----------- ----------- ----------- ----------- ----------- ----------- Net assets available for benefits $13,716,282 $11,694,364 $ 1,727,160 $ 3,458,050 $22,598,708 $ 4,786,256 =========== =========== =========== =========== =========== =========== The accompanying notes are an integral part of these financial statements. Page 6

ARCH COAL, INC. EMPLOYEE THRIFT PLAN STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS, WITH FUND INFORMATION Year Ended December 31, 1998 Barclays Arch Coal, ARCO S&P 500 Primco Twentieth Inc. Common Common Equity Index Stable Value Century Total Stock Fund Stock Fund Fund Fund Ultra Fund ------------ ----------- ----------- ----------- ----------- ----------- Additions to net assets attributed to: Investment income Realized and unrealized gains(losses) $ 8,818,097 $(1,155,885) $(3,986,260) $ 2,934,739 - $ 4,542,093 Interest and dividend income 4,694,440 82,677 458,203 - $2,162,194 - ------------ ----------- ----------- ----------- ----------- ----------- Net investment income 13,512,537 (1,073,208) (3,528,057) 2,934,739 2,162,194 4,542,093 ------------ ----------- ----------- ----------- ----------- ----------- Contributions Participant 12,801,026 269,118 - 1,566,476 2,236,043 1,808,948 Employer 7,357,213 141,429 - 893,833 1,820,822 928,101 ------------ ----------- ----------- ----------- ----------- ----------- Total contributions 20,158,239 410,547 - 2,460,309 4,056,865 2,737,049 ------------ ----------- ----------- ----------- ----------- ----------- Total additions 33,670,776 (662,661) (3,528,057) 5,395,048 6,219,059 7,279,142 ------------ ----------- ----------- ----------- ----------- ----------- Deductions from net assets attributed to: Benefits paid to participants 16,285,931 190,125 541,128 1,377,106 7,858,544 650,738 Administrative expenses 40,137 332 1,634 4,164 10,775 4,711 ------------ ----------- ----------- ----------- ----------- ----------- Total deductions 16,326,068 190,457 542,762 1,381,270 7,869,319 655,449 ------------ ----------- ----------- ----------- ----------- ----------- Net increase (decrease) prior to transfers 17,344,708 (853,118) (4,070,819) 4,013,778 (1,650,260) 6,623,693 Interfund transfers, net - 1,245,890 (2,706,416) 10,606,601 (396,044) 9,385,184 Transfers from other plans 91,224,911 2,323,833 26,900,707 6,304,572 24,421,050 5,587,602 Loan principal and interest repayments (3,729,133) - - - - - New loans issued to participants 5,114,362 - - - - - ------------ ----------- ----------- ----------- ----------- ----------- Net increase (decrease) 109,954,848 2,716,605 20,123,472 20,924,951 22,374,746 21,596,479 Net assets available for benefits, Beginning of year 95,538,168 91,195 - - 22,598,708 - ------------ ----------- ----------- ----------- ----------- ----------- End of year $205,493,016 $ 2,807,800 $20,123,472 $20,924,951 $44,973,454 $21,596,479 ============ =========== =========== =========== =========== =========== The accompanying notes are an integral part of these financial statements. Page 7

ARCH COAL, INC. EMPLOYEE THRIFT PLAN STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS, WITH FUND INFORMATION (Continued) Year Ended December 31, 1998 Twentieth American Century Benham Century Franklin MAS Value J.P. Morgan International GNMA Income and Balance Institutional Diversified Growth Fund Fund Growth Fund Sheet Fund Fund Fund ------------ ----------- ----------- ----------- ----------- ----------- Additions to net assets attributed to: Investment income Realized and unrealized gains(losses) $ 646,647 $ (28,962) $ 5,006,098 $ (201,855) $ (288,464) $ 730,436 Interest and dividend income 10,428 366,264 304,624 118,100 5,629 135,307 ------------ ----------- ----------- ----------- ----------- ----------- Net investment income 657,075 337,302 5,310,722 (83,755) (282,835) 865,743 ------------ ----------- ----------- ----------- ----------- ----------- Contributions Participant 592,330 384,307 2,328,507 744,655 1,148,371 562,325 Employer 318,908 220,556 1,195,812 396,808 602,106 255,945 ------------ ----------- ----------- ----------- ----------- ----------- Total contributions 911,238 604,863 3,524,319 1,141,463 1,750,477 818,270 ------------ ----------- ----------- ----------- ----------- ----------- Total additions 1,568,313 942,165 8,835,041 1,057,708 1,467,642 1,684,013 ------------ ----------- ----------- ----------- ----------- ----------- Deductions from net assets attributed to: Benefits paid to participants 368,259 382,389 1,635,234 308,843 896,267 426,330 Administrative expenses 1,475 1,427 5,934 1,948 2,569 1,306 ------------ ----------- ----------- ----------- ----------- ----------- Total deductions 369,734 383,816 1,641,168 310,791 898,836 427,636 ------------ ----------- ----------- ----------- ----------- ----------- Net increase (decrease) prior to transfers 1,198,579 558,349 7,193,873 746,917 568,806 1,256,377 Interfund transfers, net 2,993,948 6,023,493 15,543,654 4,670,793 6,562,995 3,754,007 Transfers from other plans 2,060,782 1,617,041 7,467,260 2,235,242 3,791,621 1,658,906 Loan principal and interest repayments - - - - - - New loans issued to participants - - - - - - ------------ ----------- ----------- ----------- ----------- ----------- Net increase (decrease) 6,253,309 8,198,883 30,204,787 7,652,952 10,923,422 6,669,290 Net assets available for benefits, Beginning of year - - - - - - ------------ ----------- ----------- ----------- ----------- ----------- End of year $ 6,253,309 $ 8,198,883 $30,204,787 $ 7,652,952 $10,923,422 $ 6,669,290 ============ =========== =========== =========== =========== =========== The accompanying notes are an integral part of these financial statements. Page 8

ARCH COAL, INC. EMPLOYEE THRIFT PLAN STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS, WITH FUND INFORMATION (Continued) Year Ended December 31, 1998 Schwab INVESCO INVESCO Dodge & Cox Personal Intermediate Select INVESCO Balanced Choice Loan Government Income High Yield Fund Account Fund Fund Bond Fund Fund Bond Fund ------------ ----------- ----------- ----------- ----------- ----------- Additions to net assets attributed to: Investment income Realized and unrealized gains(losses) $ 365,220 $ 254,290 - - - - Interest and dividend income 457,365 13,777 $ 579,872 - - - ------------ ----------- ----------- ----------- ----------- ----------- Net investment income 822,585 268,067 579,872 - - - ------------ ----------- ----------- ----------- ----------- ----------- Contributions Participant 1,159,946 - - - - - Employer 582,893 - - - - - ------------ ----------- ----------- ----------- ----------- ----------- Total contributions 1,742,839 - - - - - ------------ ----------- ----------- ----------- ----------- ----------- Total additions 2,565,424 268,067 579,872 - - - ------------ ----------- ----------- ----------- ----------- ----------- Deductions from net assets attributed to: Benefits paid to participants 1,325,536 - 325,432 - - - Administrative expenses 3,862 - - - - - ------------ ----------- ----------- ----------- ----------- ----------- Total deductions 1,329,398 - 325,432 - - - ------------ ----------- ----------- ----------- ----------- ----------- Net increase (decrease) prior to transfers 1,236,026 268,067 254,440 - - - Interfund transfers, net 8,786,077 1,591,827 - (8,091,573) (7,346,224) (2,904,865) Transfers from other plans 2,941,536 - 3,914,759 - - - Loan principal and interest repayments - - (3,729,133) - - - New loans issued to participants - - 5,114,362 - - - ------------ ----------- ----------- ----------- ----------- ----------- Net increase (decrease) 12,963,639 1,859,894 5,554,428 (8,091,573) (7,346,224) (2,904,865) Net assets available for benefits, Beginning of year - - 4,786,256 8,091,573 7,346,224 2,904,865 ------------ ----------- ----------- ----------- ----------- ----------- End of year $ 12,963,639 $ 1,859,894 $10,340,684 - - - ============ =========== =========== =========== =========== =========== The accompanying notes are an integral part of these financial statements. Page 9

ARCH COAL, INC. EMPLOYEE THRIFT PLAN STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS, WITH FUND INFORMATION (Continued) Year Ended December 31, 1998 INVESCO INVESCO INVESCO INVESCO Total Industrial INVESCO International Emerging Return Income Dynamics Growth Growth Fund Fund Fund Fund Fund ------------ ----------- ----------- ----------- ----------- Additions to net assets attributed to: Investment income Realized and unrealized gains(losses) - - - - - Interest and dividend income - - - - - ------------ ----------- ----------- ----------- ----------- Net investment income - - - - - ------------ ----------- ----------- ----------- ----------- Contributions Participant - - - - - Employer - - - - - ------------ ----------- ----------- ----------- ----------- Total contributions - - - - - ------------ ----------- ----------- ----------- ----------- Total additions - - - - - ------------ ----------- ----------- ----------- ----------- Deductions from net assets attributed to: Benefits paid to participants - - - - - Administrative expenses - - - - - ------------ ----------- ----------- ----------- ----------- Total deductions - - - - - ------------ ----------- ----------- ----------- ----------- Net increase (decrease) prior to transfers - - - - - Interfund transfers, net $(19,123,491) $(13,716,282) $(11,694,364) $(1,727,160) $(3,458,050) Transfers from other plans - - - - - Loan principal and interest repayments - - - - - New loans issued to participants - - - - - ------------ ------------ ------------ ----------- ----------- Net increase (decrease) (19,123,491) (13,716,282) (11,694,364) (1,727,160) (3,458,050) Net assets available for benefits, Beginning of year 19,123,491 13,716,282 11,694,364 1,727,160 3,458,505 ------------ ------------ ------------ ----------- ----------- End of year - - - - - ============ ============ ============ =========== =========== The accompanying notes are an integral part of these financial statements. Page 10

ARCH COAL, INC. EMPLOYEE THRIFT PLAN NOTES TO FINANCIAL STATEMENTS DECEMBER 31, 1998 and 1997 NOTE 1 - DESCRIPTION OF PLAN The Arch Coal, Inc. Employee Thrift Plan (the Plan) was established by Arch Coal, Inc. (the Company), formerly known as Arch Mineral Corporation, for the benefit of the eligible employees of the Company, its subsidiaries and controlled affiliates. The following description of the Plan reflects 1998 plan amendments and provides only general information. Participants should refer to the Summary Plan Description, copies of which are available from the Company, for a more complete description of the Plan's provisions. Certain provisions of the Plan as described below do not apply to or have been modified for certain subsidiaries and affiliates of the Company. General The Plan is a defined contribution plan established by the Company under the provisions of Section 401(a) of the Internal Revenue Code (IRC), which includes a qualified deferred arrangement as described in Section 401(k) of the IRC, for the benefit of eligible employees. The Plan is subject to the provisions of the Employee Retirement Income Security Act of 1974 (ERISA). The Company has established a Pension Committee to oversee the activities of the Plan and has appointed the Senior Vice President - Law and Human Resources as Plan Administrator. Chase Manhattan Bank is the Plan's trustee. INVESCO Retirement Plan Services was the Plan Trustee through December 31, 1997. American Century Retirement Plan Services is the Plan's recordkeeper. Eligibility Participation in the Plan is open to all full-time salaried employees, all full-time nonunion hourly employees, and certain union employees where specified by applicable collective bargaining agreements, of the Company, its subsidiaries, and any controlled affiliates that elect to participate in the Plan. Page 11

NOTE 1 - DESCRIPTION OF PLAN (Continued) Participant Accounts Individual accounts are maintained for each participant to reflect the participant's share of the Plan's income, the Company's contribution and the participant's contribution. Allocations are based on participant account balances, as defined. Contributions Participants may contribute up to 16% of compensation, as defined by the Plan, on a pre-tax, after-tax, or combined basis. The Company matches 100% of the first 6% of compensation contributed by each participant. Participant and Company contributions are made with each weekly or biweekly payroll. Contributions to the plan, including employee and employer contributions, are subject to various limitations imposed by the Internal Revenue Code. Vesting Participants are fully vested in their contributions and all earnings thereon. All eligible employees of the Company at December 31, 1997 became fully vested in the Plan. Eligible employees hired subsequent to December 31, 1997 vest in Company contributions and earnings thereon upon the completion of three full and consecutive years of service. All participants become fully vested upon death while employed, total disability or at normal retirement age (age 65), regardless of the number of months of participation. Forfeitures of terminated participants' nonvested amounts are used to reduce the Company's future contributions. Restoration of such forfeitures to reemployed participants is made in accordance with the Plan's provisions. Withdrawals Upon death, disability, retirement, or termination of employment, a participant may elect to withdraw the value of the participant's vested interest in his or her account. The normal form of payment is a lump-sum distribution. Alternative forms of payment include annuity purchase, installments, and direct rollover. Page 12

NOTE 1 - DESCRIPTION OF PLAN (Continued) Withdrawals (Continued) Active participants can make hardship withdrawals of pre-tax employee contributions in certain circumstances and can make withdrawals of vested employer contributions, after-tax employee contributions, or rollover contributions on a non-hardship basis. All such withdrawals are subject to various restrictions and may be subject to income tax penalties. Loans to Participants Participants who have been in the Plan for at least 12 months may borrow a portion of their account in accordance with the provisions of the Plan. No loan shall be made if, immediately after the loan, the unpaid balance of all loans to the participant would exceed the lesser of $50,000 or 50% of the vested portion of the participant's account. The maximum loan repayment period for loans not used for the acquisition of a participant's personal residence is five years. If a loan is used for the acquisition of a participant's primary residence, the maximum repayment period is 15 years. All outstanding participant loans must be repaid upon the participant's termination of employment with the Company. Loans are secured by assignment of the participant's account and the participant's collateral promissory note for the amount of the loan. Interest rates are based on the prime rate on the first working day of the month in which the loans are made. Investment Options Participants direct contributions, including Company matching contributions, into one or more investment options in 1% increments. Participants may change their investment elections daily. A description of each investment option available at December 31, 1998 is provided below: o Arch Coal, Inc. Common Stock Fund - Funds are invested in Arch Coal, Inc. common stock. Page 13

NOTE 1 - DESCRIPTION OF PLAN (Continued) Investment Options (Continued) o ARCO Common Stock Fund - Funds are invested in common stock of the Atlantic Richfield Company (Arco). This fund option is only available to former employees of Arco who became employees of the Company through the Company's acquisition of Arco's coal operations, as further described in Note 3. No contributions or transfers into this fund option are allowed. Furthermore, this fund option is temporary and participants must transfer any remaining balances to other options on or before December 31, 2003. o Primco Stable Value Fund - This fund, formerly known as the Capital Preservation Fund, invests in long-term investment contracts issued by a variety of insurance carriers, a collective trust, a pooled separate account, and a money market fund. The objective of this fund is to generate current income, while providing protection against loss of capital. The investment contracts included in this fund had average yields of 6.01% and 7.39% for the years ended December 31, 1998 and 1997, respectively. The average crediting interest rates were 5.54% and 7.34% for December 31, 1998 and 1997, respectively. The fair value of guaranteed insurance contracts approximates contract value at December 31, 1998 and 1997. o American Century Benham GNMA Fund - This fund invests in mortgage-backed Ginnie Mae certificates. The investment objective is to generate current interest income while limiting exposure to loss of capital. o Dodge & Cox Balanced Fund - This fund invests in a combination of stocks and bonds and seeks to provide current income and the opportunity for long-term growth. o J.P. Morgan Diversified Fund - This fund invests in a combination of stocks and bonds and seeks to provide current income and the opportunity for long-term growth. o American Century Income and Growth Fund - This fund invests primarily in dividend-paying common stocks and seeks to provide current income and long-term growth. Page 14

NOTE 1 - DESCRIPTION OF PLAN (Continued) Investment Options (Continued) o MAS Value Institutional Fund - This fund invests primarily in common stocks and seeks long-term growth by following a value-oriented investment approach. o Franklin Balance Sheet Fund - This fund invests in common stocks, preferred stocks, and debt securities and seeks high total return and long-term growth by following a value-oriented investment approach. o Barclays S & P 500 Equity Index Fund - This fund invests in a broad portfolio of common stocks and seeks to track the performance of the Standard & Poor's 500 Index. o Twentieth Century Ultra Fund - This fund invests primarily in common stocks with above-average growth potential and above-average price volatility. o Twentieth Century International Growth Fund - This fund invests primarily in commons stocks of foreign companies and seeks long-term growth subject to the volatility inherent in international investing. o Schwab Personal Choice Account - This is an option wherein a plan participant can make self-directed investments directly in equity and debt securities through a Charles Schwab & Company brokerage account. Participants are limited to investing 25% of their account balances through this option. Administrative Expenses The Company pays the salaries and related benefits of employees who administer the Plan. Participants pay loan fees. All other administrative expenses are paid by the Plan. Administrative expenses do not include investment advisory fees, which directly reduce net investment income. Plan Termination Although it has not expressed any intent to do so, the Company has the right under the Plan to discontinue its contributions at any time and to terminate the Plan subject to the provisions set forth in ERISA. In the event of Plan termination, participants will become fully vested in their accounts. The net assets of the Plan will be allocated to provide benefits to participants as prescribed by ERISA. Page 15

NOTE 2 - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Accounting The accompanying financial statements are prepared on the accrual basis of accounting. Investment Valuation Investments of the Plan are stated at fair value. Publicly traded Securities are valued at their quoted market prices. Investments in mutual funds are valued at published market value on the last business day of the plan year. Investment contracts are stated at contract value (which represents cost plus accumulated interest, less funds to pay certain benefits and loans to participants) because they are fully benefit responsive. The fair value of the participation units owned by the Plan in the collective trust funds and pooled separate accounts are based on quoted redemption values on the last business day of the plan year. Participant notes receivable are valued at their outstanding balances, which approximates fair value. Purchases and sales of securities are recorded on a trade-date basis. Interest income is recorded on the accrual basis. Dividends are recorded on the ex-dividend date. Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. NOTE 3 - PLAN MERGERS AND ASSET TRANSFERS On January 1, 1998, the Company merged three similar plans sponsored by the Company and its subsidiaries into the Plan and amended the Plan to reflect this merger. The value of assets transferred is based on the value of the assets of the merged plans as of December 31, 1997. Effective June 1, 1998, in connection with the Company's acquisition of the domestic coal related operations of Arco, certain Arco defined contribution plan assets allocated to former Arco employees who became employees of the Company and its affiliates as a result of the acquisition were transferred to the Plan. The Plan was amended to reflect and allow this asset transfer. Page 16

NOTE 3 - PLAN MERGERS AND ASSET TRANSFERS (Continued) The assets transferred to the Plan as a result of these plan mergers and asset transfers during the year ended December 31, 1998 are as follows: Assets Transfer from Transferred -------------------------------------------------- ----------- Ashland Coal, Inc. Employee Thrift Plan $29,108,983 Mingo Logan Coal Company Retirement Plan and Mingo Logan Hourly Employees Savings Plan 7,799,114 Coal Mac, Inc. Savings and Retirement Plan 4,767,169 Arco Thrift and Savings Plans 49,549,645 =========== $91,224,911 =========== NOTE 4 - INVESTMENTS The Plan's investments are held by a trust fund and are presented in the following table. December 31, --------------------------- 1998 1997 ----------- ----------- Investments at fair value determined by quoted market price: Common stocks Arch Coal, Inc.,160,738 and 9,668 shares $ 2,787,504 $ 91,195 Atlantic Richfield Company, 308,325 shares 20,123,472 - Schwab Personal Choice Accounts, various investments 1,859,894 - ----------- ----------- 24,770,870 91,195 ----------- ----------- Mutual funds Twentieth Century Ultra Fund, 642,666 shares 21,471,454 - Twentieth Century International Growth Fund, 648,734 shares 6,214,873 - Benham GNMA Fund, 764,369 shares 8,171,106 - Page 17

NOTE 4 - INVESTMENTS (Continued) December 31, ---------------------------- 1998 1997 ----------- ----------- Mutual Funds (continued) American Century Income and Growth Fund, 1,027,329 shares $30,049,366 - Franklin Balance Sheet Fund, 240,845 shares 7,610,710 - MAS Value Institutional Fund, 750,647 shares 10,861,857 - J.P. Morgan Diversified Fund, 427,755 shares 6,634,479 - Dodge & Cox Balanced Fund, 197,783 shares 12,899,397 - INVESCO Intermediate Government Bond Fund, 644,747 shares - $ 8,091,573 INVESCO Select Income Fund, 1,101,383 shares - 7,346,224 INVESCO High Yield Bond Fund, 288,228 shares - 2,904,865 INVESCO Total Return Fund, 657,391 shares - 19,123,491 INVESCO Industrial Income Fund, 919,938 shares - 13,716,282 INVESCO Dynamics Fund, 837,705 shares - 11,694,364 INVESCO International Growth Fund, 128,318 shares - 1,727,160 INVESCO Emerging Growth Fund, 308,479 shares - 3,458,050 INVESCO Treasurer's Fund, 623,445 shares - 623,445 ----------- ----------- 103,913,242 68,685,454 ----------- ----------- Page 18

NOTE 4 - INVESTMENTS (Continued) December 31, --------------------------- 1998 1997 ----------- ---------- Collective trust funds I.R.T. Stable Value Fund - $13,820,591 Barclay S&P 500 Equity Index Fund, 711,053 units $20,826,732 - Chase Manhattan Bank Pooled Cash Investment Fund 3,269,712 - ----------- ----------- 24,096,444 13,820,591 ----------- ----------- Investments at Contract Value Pooled separate account John Hancock Mutual Life 5,240,652 2,020,411 Allstate Life Insurance Co. #77071-IOT 1,048,644 - Bankers Trust Delaware #98-936IOT 6,237,925 - State Street Bank & Trust #98239 6,043,218 - Transamerica Life & Annuity #76863 3,030,571 - ----------- ----------- 21,601,010 2,020,411 ----------- ----------- Investment contracts Allstate Life Insurance Co. #77057 8,070,916 - Commonwealth Life Insurance, #00128TR-1 - 992,408 Commonwealth Life Insurance, #00128TR-2 - 947,123 Commonwealth Life Insurance, #00128TR-3 1,025,478 999,611 Commonwealth Life Insurance, #00128TR-4 518,639 521,357 Commonwealth Life Insurance, #00128TR-5 240,378 502,380 Commonwealth Life Insurance, #00128TR-6 515,330 516,254 Commonwealth Life Insurance, #00128TR-7 1,025,994 1,027,185 Commonwealth Life Insurance, #00128TR-10 1,027,171 - Page 19

NOTE 4 - INVESTMENTS (Continued) December 31, --------------------------- 1998 1997 ----------- ----------- Investment Contracts (continued) Commonwealth Life Insurance, #00128TR-12 $ 1,019,159 - Commonwealth Life Insurance, #00128TR-13 1,012,274 - Commonwealth Life Insurance, #00128TR-14 953,315 - State Street Bank & Trust #98012 2,533,139 - United of Omaha Life Insurance, #11491 501,348 $ 501,451 Business Men's Assurance MBIA #1325 1,512,550 - ----------- ----------- 19,955,691 6,007,769 ----------- ----------- Investments at estimated fair value Participant notes receivable, 8-9% 10,340,684 4,786,256 ----------- ----------- $204,677,941 $95,411,676 ============ =========== NOTE 5 - TAX STATUS OF THE PLAN The plan obtained its latest determination letter on August 9, 1996, in which the Internal Revenue Service stated that the plan, as then designed, was in compliance with the applicable requirements of the Internal Revenue Code. The plan has been amended since receiving the determination letter. However, the plan administrator and the plan's tax counsel believe that the plan is currently designed and being operated in compliance with the applicable requirements of the Internal Revenue Code. Therefore, no provision for income taxes has been included in the plan's financial statements. NOTE 6 - TRANSACTIONS WITH PARTIES-IN-INTEREST The Company engages the services of a third-party service provider to assist it in carrying out certain administrative and recordkeeping functions under the Plan. The Plan has investments in the common stock of the Company as well as in mutual funds and a collective trust sponsored by the third-party service provider of the Plan. Page 20

NOTE 7 - YEAR 2000 ISSUE (UNAUDITED) The Company has developed a plan to modify its internal information technology to be ready for the year 2000 and is converting critical data processing systems. The project also includes determining whether third-party service providers have reasonable plans in place to become year 2000 compliant. The Company currently expects the project to be substantially complete by the third quarter of 1999. The Company does not expect this project to have a significant effect on plan operations. Page 21

SUPPLEMENTAL SCHEDULES ARCH COAL, INC. EMPLOYEE THRIFT PLAN Line 27(a) - SCHEDULE OF ASSETS HELD FOR INVESTMENT PURPOSES December 31, 1998 Description of Investment Including Maturity Date, Identity of Issue, Borrower, Rate of Interest, Par or Current Lessor, or Similar Party Maturity Value Cost Value - ---------------------------------------- ------------------------ ------------ ------------ Common stock: Arch Coal, Inc. Stock Fund 160,738 shares $ 3,796,016 $ 2,787,504 Atlantic Richfield Company Stock Fund 308,325 shares 24,126,431 20,123,472 Schwab various 1,605,604 1,859,894 ------------ ------------ 29,528,051 24,770,870 ------------ ------------ Mutual funds: Twentieth Century Ultra Fund 642,666 shares 18,948,618 21,471,454 Twentieth Century International Growth Fund 648,734 shares 5,395,695 6,214,873 Benham GNMA Fund 764,369 shares 8,185,031 8,171,106 American Century Income and Growth Fund 1,027,329 shares 26,237,333 30,049,366 Franklin Balance Sheet Fund 240,845 shares 8,113,716 7,610,710 MAS Value Institutional Fund 750,647 shares 12,847,404 10,861,857 J.P. Morgan Diversified Fund 427,755 shares 6,058,505 6,634,479 Dodge & Cox Balanced Fund 197,783 shares 13,260,046 12,899,397 ------------ ------------ 99,046,348 103,913,242 ------------ ------------ Investment contracts: Allstate Life Insurance Co. 8,070,916 8,070,916 Commonwealth Life Insurance Company, contract #00128TR3 1,025,478 1,025,478 Commonwealth Life Insurance Company, contract #00128TR4 518,639 518,639 Commonwealth Life Insurance Company, contract #00128TR5 240,378 240,378 Commonwealth Life Insurance Company, contract #00128TR6 515,330 515,330 Commonwealth Life Insurance Company, contract #00128TR7 1,025,994 1,025,994 Commonwealth Life Insurance Company, contract #00128TR10 1,027,171 1,027,171 Commonwealth Life Insurance Company, contract #00128TR12 1,019,159 1,019,159 Commonwealth Life Insurance Company, contract #00128TR13 1,012,274 1,012,274 Commonwealth Life Insurance Company, contract #00128TR14 953,315 953,315 State Street Bank & Trust 2,533,139 2,533,139 United of Omaha Life Insurance 501,348 501,348 Business Men's Assurance MBIA 1,512,550 1,512,550 ------------ ------------ 19,955,691 19,955,691 ------------ ------------ See independent auditors' report. Page 22

ARCH COAL, INC. EMPLOYEE THRIFT PLAN Line 27(a) - SCHEDULE OF ASSETS HELD FOR INVESTMENT PURPOSES (Continued) December 31, 1998 Description of Investment Including Maturity Date, Identity of Issue, Borrower, Rate of Interest, Par or Current Lessor, or Similar Party Maturity Value Cost Value - ---------------------------------------- ------------------------- ------------ ------------ Collective trust: Barclay S&P 500 Equity Index Fund 711,053 units $ 17,990,212 $20,826,732 Chase Manhattan Bank Pooled Cash Investment Fund 3,368,882 units 3,269,712 3,269,712 ------------ ------------ 21,259,924 24,096,444 ------------ ------------ Pooled separate account: John Hancock Mutual Life 5,240,652 5,240,652 Allstate Life Insurance Co. 1,048,644 1,048,644 Bankers Trust Delaware 6,237,925 6,237,925 State Street Bank & Trust 6,043,218 6,043,218 Transamerica Life & Annuity 3,030,571 3,030,571 ------------ ------------ 21,601,010 21,601,010 ------------ ------------ Loans to participants 8-9% - 10,340,684 ------------ ------------ $191,391,024 $204,677,941 ============ ============ See independent auditors' report Page 23

ARCH COAL, INC. EMPLOYEE THRIFT PLAN LINE 27(d) - SCHEDULE OF REPORTABLE TRANSACTIONS Year Ended December 31, 1998 Current Value Description Purchase Selling Cost of on Transaction Net Gain Identity of Party Involved of Asset Price Price Asset Date (Loss) - ----------------------------- ----------- ----------- ----------- ----------- ----------- ----------- Series of Transactions in excess of 5% of the Current Value of Plan Assets at the Beginning of the Year: Twentieth Century Mutual Fund $20,551,999 $20,551,999 $20,551,999 Ultra Fund $ 4,610,893 4,374,463 4,610,893 $ 236,430 Twentieth Century Mutual Fund 7,245,702 7,245,702 7,245,702 International Growth Fund 1,529,079 1,444,197 1,529,079 84,882 Benham GNMA Mutual Fund 10,287,688 10,287,688 10,287,688 Fund 2,463,325 2,468,568 2,463,325 (5,243) American Century Mutual Fund 30,419,967 30,419,967 30,419,967 Income & Growth Fund 6,124,302 5,701,101 6,124,302 423,201 J.P. Morgan Diversified Fund Mutual Fund 6,916,658 6,916,658 6,916,658 1,163,040 1,110,927 1,163,040 52,113 Dodge & Cox Mutual Fund 17,480,778 17,480,778 17,480,778 Balanced Fund 5,349,788 5,285,276 5,349,788 64,512 Chase Manhattan Bank Pooled Collective 66,574,763 66,574,763 66,574,763 Cash Investment Fund Trust 63,205,881 63,205,881 63,205,881 - Transamerica Pooled Separate 6,030,571 6,030,571 6,030,571 Contract #76862 Account 3,000,000 3,000,000 3,000,000 - State Street Bank Investment 5,755,649 5,755,649 5,755,649 Contract #98011 Contract 3,222,510 3,222,510 3,222,510 - Allstate Life Insurance Investment 12,006,115 12,006,115 12,006,115 Contract #77056 Contract 3,935,199 3,935,199 3,935,199 - See independent auditors' report Page 24

ARCH COAL, INC. EMPLOYEE THRIFT PLAN LINE 27(d) - SCHEDULE OF REPORTABLE TRANSACTIONS Year Ended December 31, 1998 Current Value Description Purchase Selling Cost of on Transaction Net Gain Identity of Party Involved of Asset Price Price Asset Date (Loss) - ----------------------------- ----------- ----------- ----------- ----------- ----------- ------------- Single Transaction Exceeding 5% of the Current Value of Plan Assets at the Beginning of the Year: INVESCO Intermediate Government Bond Fund Mutual Fund $ 8,091,573 $ 8,098,148 $ 8,091,573 $ (6,575) INVESCO Select Income Fund Mutual Fund 7,346,224 7,183,420 7,346,224 162,804 INVESCO Total Return Fund Mutual Fund 19,123,491 14,148,131 19,123,491 4,975,360 INVESCO Industrial Income Fund Mutual Fund 13,716,282 12,076,366 13,716,282 1,639,916 INVESCO Dynamics Fund Mutual Fund 11,694,364 10,926,678 11,694,364 767,686 Twentieth Century Ultra Fund Mutual Fund $ 6,774,814 6,774,814 6,774,814 American Century Income and Mutual Fund 11,659,192 11,659,192 11,659,192 Growth Fund Dodge & Cox Balanced Fund Mutual Fund 10,546,639 10,546,639 10,546,639 Chase Manhattan Bank Pooled Collective 66,574,763 66,574,763 66,574,763 Cash Investment Fund Trust Fund 63,205,881 63,205,881 63,205,881 - Transamerica Pooled Separate 6,000,000 6,000,000 6,000,000 Contract #76863 Account State Street Bank Investment 5,705,555 5,705,555 5,705,555 Contract #98012 Contract Allstate Life Insurance Investment 11,598,905 11,598,905 11,598,905 Contract #77057 Contract State Street Bank Pooled Separate 6,000,000 6,000,000 6,000,000 Contract #98239 Account Bankers Trust Pooled Separate 6,000,000 6,000,000 6,000,000 Contract #98-936 Account IRT Stable Value Fund Collective 13,820,591 13,820,591 13,820,591 - Trust Fund See independent auditors' report. Page 25

SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the duly authorized Plan Administrator has executed this annual report. ARCH COAL, INC. EMPLOYEE THRIFT PLAN Date: June 30, 1999 By: /s/ Jeffry N. Quinn --------------------- Jeffry N. Quinn, Plan Administrator

INDEX TO EXHIBITS EXHIBIT ITEM 23.1 Consent of Ernst & Young LLP, Independent Auditors 23.2 Consent of Stone Carlie & Company, L.L.C., Independent Auditors


                        CONSENT OF INDEPENDENT AUDITORS



We consent to the incorporation by reference in the Registration Statement (Form
S-8 No. 333-32777) pertaining to the Arch Coal, Inc. Employee Thrift Plan of our
report  dated  June 25,  1998,  with  respect  to the  statement  of net  assets
available for benefits,  with fund  information of the Arch Coal, Inc.  Employee
Thrift Plan as of December 31, 1997  included in this Annual  Report (Form 11-K)
for the year ended December 31, 1998.

                                                        /s/ Ernst & Young LLP
                                                       -------------------------
Louisville, Kentucky                                   Ernst & Young LLP
June 28, 1999






                        CONSENT OF INDEPENDENT AUDITORS


We consent to the incorporation by reference in the Registration Statement (Form
S-8 No. 333-32777) pertaining to the Arch Coal, Inc. Employee Thrift Plan of our
report  dated June 25,  1999,  with  respect to the  financial  statements  with
supplemental  schedules of Arch Coal, Inc. Employee Thrift Plan included in this
Annual Report on Form 11-K for the year ended December 31, 1998.




 /s/ Stone Carlie & Company, L.L.C.
- -----------------------------------
Stone Carlie & Company, L.L.C.

St. Louis, Missouri
June 25, 1999