Exhibit 99.1

FOR IMMEDIATE RELEASE

October 27, 2011

Contact: Cloud Peak Energy Inc.
Karla Kimrey
Vice President, Investor Relations
720-566-2900

CLOUD PEAK ENERGY INC. ANNOUNCES RESULTS FOR
THIRD QUARTER AND FIRST NINE MONTHS OF 2011

Gillette, WY, October 27, 2011 — Cloud Peak Energy Inc. (NYSE:CLD), one of the largest U.S. coal producers and the only pure-play Powder River Basin (PRB) coal company, today announced results for the third quarter and first nine months of 2011.

2011 Third Quarter and Nine Months Highlights

·                  Adjusted EBITDA(1) of $87.9 million in the third quarter of 2011 compared with $94.5 million in the third quarter of 2010; Adjusted EBITDA of $258.8 million compared with $253.1 million for the first nine months of 2010.

·                  Net income of $24.6 million resulting in Adjusted EPS(1) of $0.61 compared to $0.60 in the third quarter of 2010; for the nine months 2011, net income of $146.0 million resulting in Adjusted EPS of $1.78 compared to $1.39 in the first nine months of 2010.

·                  Diluted EPS of $0.41 compared to a loss of $0.22 in the third quarter of 2010; diluted EPS of $2.41 compared to $0.68 in the first nine months of 2010.

·                  Asian exports were up approximately 48 percent to 1.4 million tons from 0.9 million tons in the third quarter of 2010.  For the first nine months, Asian exports were 3.7 million tons up 47 percent from 2.5 million tons exported in the first nine months of 2010.

·                  Cash and cash equivalents increased to $437.6 million during the third quarter of 2011 following the release of $86.6 million from previously restricted cash, and cash flow from operations of $93.7 million in the third quarter.

“Our third quarter was highlighted by our mines’ continued strong operating performance and the continued expansion of our Asian exports by 48 percent over the third quarter of last year,” said Colin Marshall, President and Chief Executive Officer.  “Flooding in the Midwest affected railroad performance from May to September; however, by late September the railroads’ performance had returned to normal, which has allowed us to

(1)  Defined later.

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improve our full-year guidance.  Costs are under control and our exports are expected to be above 4.5 million tons for the full year.”

Operating Highlights(1)

(1)Includes the three company-operated mines only.

For the third quarter, sales from our three company-operated mines were 24.4 million tons, down from 25.1 million tons in the third quarter of 2010 due to flood related interruptions to rail services which reduced shipments from May to mid-September.  Adjusted EBITDA declined slightly to $87.9 million, driven by lower volumes.  Realized price per ton increased to $12.91.  Average cost of product sold per ton was $9.17, up from last year due to the lower volumes mined, higher diesel prices, increased repairs and maintenance, and higher strip ratios.  For the first nine months, we generated Adjusted EBITDA of $258.8 million up from $253.1 million for the same period in 2010 driven by strong export sales and higher realized prices.

Health, Safety and Environment Record

During the first nine months of 2011, of our approximately 1,550 employees, we suffered 10 minor reportable injuries resulting in a year-to-date MSHA All Injury Frequency Rate of 0.91, an increase over the full year 2010 rate of 0.58.  We continue to focus on the safety of all of our employees and contractors.

Balance Sheet and Cash Flow

Cash flow from operations totaled $93.7 million for the third quarter of 2011.  Capital expenditures were $29.8 million.  Coal lease acquisition payments for the quarter were $50.2 million.

Unrestricted cash on hand as of September 30, 2011 was $437.6 million up from $326.7 million at June 30, 2011.  Cloud Peak Energy’s balance sheet continues to be well positioned with total available liquidity of $927.1 million as of September 30, 2011.  Supported by our strong operational performance, we were able to secure reductions in collateral requirements from almost all of our surety bond providers, thereby releasing $86.6 million of restricted cash during the third quarter of 2011.

During the three months ended September 30, 2011, the company completed its annual update to the undiscounted estimated liability owed to Rio Tinto under the Tax Receivable Agreement which was established in connection with the IPO.  The estimated liability was updated for the finalization of the effects of the Secondary Offering, based on the final 2010 tax returns which were completed in the third quarter.  This resulted in a $29.9 million reduction in the estimated liability and a corresponding credit to “Additional paid-in capital” in the equity section of the balance sheet.

The estimated liability was also updated for the latest life of mine budgets and operating plans.  Because of the reduced future tax benefit expected to be received as explained above, there was a further decrease in the estimated liability compared to the second quarter, resulting in a $22.9 million benefit to non-operating income for the three months ended September 30, 2011.  Also in relation to the third quarter Tax Receivable

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Agreement updates, the income tax expense line item was impacted with a net charge of $35.5 million which related to changes in deferred tax assets and valuation allowance following the updates.

The total undiscounted estimated liability owed to Rio Tinto under the Tax Receivable Agreement was $180.0 million at September 30, 2011, of which $9.4 million was classified as current and the remainder non-current.

The changes to the income statement in relation to the Tax Receivable Agreement are non-cash and non-operating in nature.  To better reflect the underlying performance of our core operations, we exclude the Tax Receivable Agreement impacts in our presentation of Adjusted EBITDA and Adjusted EPS.

Outlook

The outlook for the rest of 2011 and 2012 is positive with the operations well placed and domestic demand forecast to be stable. Again in 2012, we expect to achieve our sales target of entering each year essentially fully contracted.  We will face normal cost pressures due to increasing workload (strip ratios and haul distances) and rising input prices for parts, tires, wages and fuel.  Knowing how much we expect to ship reduces production variations at the mines greatly improving operating efficiency and allowing us to concentrate on productivity improvement projects to help offset cost increases.  For 2012, we have currently contracted to sell 92 million tons, of which 82 million tons are under fixed-price contracts with a weighted-average price of $13.44 per ton.  For 2013, we have currently contracted to sell 73 million tons from our three company-operated mines.  Of this committed 2013 production, 57 million tons are under fixed-price contracts with a weighted-average price of $14.25 per ton.

A major uncertainty for the medium term is the impact of the multiple environmental regulations that are currently facing coal burning utilities.  On August 8, 2011, the U.S. Environmental Protection Agency (“EPA”) published the Cross-State Air Pollution Rule (“CSAPR”).  Since CSAPR was announced, with its January 1, 2012 start date, there has been increased interest in our low sulfur Antelope coal and an associated increase in price relative to the standard 0.8 lbs SO2/mmBtu.  However, the uncertainty around CSAPR and possible delays related to the many legal challenges are now causing some utilities to hold back on coal purchases as they try to work out the best approach for their power plants.

For Cloud Peak Energy, it currently appears that CSAPR will increase demand for ultra-low sulfur Antelope coal while the impact on domestic demand for Spring Creek and Cordero Rojo coal is not yet clear.  The longer term impact of CSAPR will depend on, among other things, the final form and possible delay to the rule, the extent of fuel switching, installation of scrubbers, plant closures and reduced operating hours.

The medium term impacts of CSAPR and other proposed rules such as the Utility MACT are uncertain; however, it does appear they will increase the cost of electricity with the associated reduction in US job creation and economic growth.

Cloud Peak Energy’s total 2011 Asian exports are expected to be above 4.5 million tons, around 4.0 million of which will be through the Westshore terminal in Vancouver, B.C. with the balance through the Ridley terminal in Prince Rupert, B.C.  While demand from our Asian customers remains strong, next year’s exports will again be limited by available terminal capacity.  In 2012, we will aim to export similar tonnage through Westshore by working to maximize shipments as opportunities arise through the year.  There are currently 0.3 million tons contracted to go through the Ridley terminal in 2012.  As previously disclosed, exports through the Ridley terminal incur significantly higher rail costs than through Westshore due to the longer multi railroad haul. We

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will continue to make additional sales through Ridley and also to Europe when prices and logistics make them viable.

Updated Guidance — 2011 Financial and Operational Estimates

The following table provides the company’s current outlook and assumptions for selected 2011 financial and operational metrics:

(1)Represents average Cost of Product Sold for produced coal for our three operated mines.

(2)Excluding impact of the Tax Receivable Agreement.

(3)Includes capitalized interest.

*Updated this quarter.

Conference Call Details

A conference call with management is scheduled at 5:00 p.m. ET on October 27, 2011, to review the results and current business conditions.  The call will be webcast live over the internet from the Company’s website at www.cloudpeakenergy.com under “Investor Relations”.  Participants should follow the instructions provided on the website for downloading and installing the audio applications necessary to join the webcast.  Interested individuals also can access the live conference call via telephone at 866.770.7125 (domestic) or 617.213.8066 (international) and entering pass code 28966800.

Following the live web cast, a replay will be available at the same URL on the company’s Web site for seven days.  A telephonic replay will also be available approximately two hours after the call and can be accessed by dialing 888.286.8010 (domestic) or 617.801.6888 (international) and entering pass code 90412427.  The telephonic replay will be available for seven days.

About Cloud Peak Energy®

Cloud Peak Energy Inc. (NYSE:CLD) is headquartered in Wyoming and is one of the largest U.S. coal producers and the only pure-play PRB coal company.  As one of the safest coal producers in the nation, Cloud Peak Energy specializes in the production of low sulfur, subbituminous coal.  The company owns and operates three surface coal mines in the PRB, the lowest cost major coal producing region in the nation.  The Antelope and Cordero Rojo mines are located in Wyoming and the Spring Creek mine is located near Decker, Montana.  With approximately 1,550 employees, the company is widely recognized for its exemplary performance in its

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safety and environmental programs.  Cloud Peak Energy is a sustainable fuel supplier for approximately 4 percent of the nation’s electricity.

Cautionary Note Regarding Forward-Looking Statements

This release and our related presentation contain “forward-looking statements” within the meaning of the safe harbor provisions of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934.  Forward-looking statements are not statements of historical facts and often contain words such as “may,” “will,” “expect,” “believe,” “anticipate,” “plan,” “estimate,” “seek,” “could,” “should,” “intend,” “potential,” or words of similar meaning.  Forward-looking statements are based on management’s current expectations, beliefs, assumptions and estimates regarding our company, industry, economic conditions, government regulations and energy policies and other factors.  Forward-looking statements may include, for example, (1) our outlook for 2011 and future periods for our company, the PRB and the industry in general, and our operational, financial and export guidance; (2) anticipated economic conditions and demand by domestic and foreign utilities, including the anticipated impact on demand driven by CSAPR and other regulatory developments; (3) prices for natural gas and other alternative sources of energy used to generate electricity; (4) coal stockpile levels and the impacts on future demand; (5) our plans to replace and/or grow our coal tons; (6) business development and growth initiatives; (7) operational plans for our mines; (8) our cost management efforts; (9) industry estimates of the EIA and other third party sources; (10) estimated Tax Receivable Agreement liabilities; and (11) other statements regarding our plans, strategies, prospects and expectations concerning our business, operating results, financial condition and other matters that do not relate strictly to historical facts. These statements are subject to significant risks, uncertainties, and assumptions that are difficult to predict and could cause actual results to differ materially from those expressed or implied in the forward-looking statements.  Factors that could adversely affect our future results include, for example, (a) future economic conditions; (b) demand for our coal by the domestic electric generation industry, export demand and terminal capacity and the price we receive for our coal; (c) reductions or deferrals of purchases by major customers and our ability to renew sales contracts; (d) environmental, health, safety, endangered species or other legislation, regulations, court decisions or government actions, or related third-party regulatory legal challenges, including any new requirements (such as CSAPR) affecting the use, demand or price for coal or imposing additional costs, liabilities or restrictions on our mining operations; (e) public perceptions, third-party regulatory legal challenges or governmental actions and energy policies relating to concerns about climate change, including emissions restrictions and governmental subsidies that make wind, solar or other alternative fuel sources more cost-effective and competitive with coal; (f) operational, geological, equipment, permit, labor, weather-related and other risks inherent in surface coal mining; (g) our ability to efficiently conduct our mining operations, (h) transportation and export terminal availability, performance and costs; (i) availability, timing of delivery and costs of key supplies, capital equipment or commodities such as diesel fuel, steel, explosives and tires; (j) our ability to acquire future coal tons through the federal LBA process and necessary surface rights in a timely and cost-effective manner and the impact of third-party regulatory legal challenges, (k) access to capital and credit markets and availability and costs of credit, surety bonds, letters of credit, and insurance; (l) the impact of direct and indirect competition from coal producers and competing sources of energy, domestically and internationally; (m) litigation and other contingent liabilities; and (n) other risk factors described from time to time in the reports and registration statements we file with the Securities and Exchange Commission (“SEC”), including those in Item 1A - Risk Factors in our most recent Form 10-K and any updates thereto in our Forms 10-Q and current reports on Forms 8-K. There may be other risks and uncertainties that are not currently known to us or that we currently believe are not material.  We make forward-looking statements based on currently available information, and we assume no obligation to, and expressly disclaim any obligation to, update or revise publicly any forward-looking statements made in this release or our related presentation, whether as a result of new information, future events or otherwise, except as required by law.

Non-GAAP Financial Measures

This release and our related presentation include the non-GAAP financial measures of (1) Adjusted EBITDA and (2) Adjusted Earnings Per Share (“Adjusted EPS”).  Adjusted EBITDA and Adjusted EPS are intended to provide additional information only and do not have any standard meaning prescribed by generally accepted accounting principles in the U.S., or GAAP.  A quantitative reconciliation of net income to Adjusted EBITDA and EPS (as defined below) to Adjusted EPS is found in the tables accompanying this release.

EBITDA represents net income before (1) interest income (expense) net, (2) income tax provision, (3) depreciation and depletion, (4) amortization, and (5) accretion.  Adjusted EBITDA represents EBITDA as further adjusted to exclude specifically

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identified items that management believes do not directly reflect our core operations.  The specifically identified items are the income statement impacts, as applicable, of: (1) the Tax Receivable Agreement and (2) our significant broker contract that expired in the first quarter of 2010.

Adjusted EPS represents diluted earnings (loss) per share attributable to controlling interest (“EPS”), adjusted to exclude the estimated per share impact of the same specifically identified items used to calculate Adjusted EBITDA and described above.

Adjusted EBITDA is an additional tool intended to assist our management in comparing our performance on a consistent basis for purposes of business decision-making by removing the impact of certain items that management believes do not directly reflect our core operations.  Adjusted EBITDA is a metric intended to assist management in evaluating operating performance, comparing performance across periods, planning and forecasting future business operations and helping determine levels of operating and capital investments.  Period-to-period comparisons of Adjusted EBITDA are intended to help our management identify and assess additional trends potentially impacting our company that may not be shown solely by period-to-period comparisons of net income.  Adjusted EBITDA is also used as part of our incentive compensation program for our executive officers and others.

We believe Adjusted EBITDA and Adjusted EPS are also useful to investors, analysts and other external users of our consolidated financial statements in evaluating our operating performance from period to period and comparing our performance to similar operating results of other relevant companies.  Adjusted EBITDA allows investors to measure a company’s operating performance without regard to items such as interest expense, taxes, depreciation and depletion, amortization and accretion and other specifically identified items that are not considered to directly reflect our core operations.  Similarly, we believe our use of Adjusted EPS provides an appropriate measure to use in assessing our performance across periods given that this measure provides an adjustment for certain specifically identified significant items that are not considered to directly reflect our core operations, the magnitude of which may vary drastically from period to period and, thereby, have a disproportionate effect on the earnings per share reported for a given period.

Our management recognizes that using Adjusted EBITDA and Adjusted EPS as performance measures has inherent limitations as compared to net income, EPS or other GAAP financial measures, as these non-GAAP measures exclude certain items, including items that are recurring in nature, which may be meaningful to investors.  Adjusted EBITDA and Adjusted EPS should not be considered in isolation and do not purport to be alternatives to net income, EPS or other GAAP financial measures as a measure of our operating performance.  Because not all companies use identical calculations, our presentations of Adjusted EBITDA and Adjusted EPS may not be comparable to other similarly titled measures of other companies.  Moreover, our presentation of Adjusted EBITDA is different than EBITDA as defined in our debt financing agreements.

SOURCE: Cloud Peak Energy Inc.

Cloud Peak Energy Inc.
Karla Kimrey, 720-566-2900
Vice President, Investor Relations

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Tons Sold

CLOUD PEAK ENERGY INC.

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share data)

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CLOUD PEAK ENERGY INC.

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS

(in thousands)

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CLOUD PEAK ENERGY INC.

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

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CLOUD PEAK ENERGY INC. AND SUBSIDIARIES

RECONCILIATION OF NON-GAAP MEASURES

(in millions, except per share data)

Adjusted EBITDA

(1)   The impact of the expired significant broker contract on the Statement of Operations is a combination of net income and the amortization expense related to the contract.  All amortization expense for the periods presented was attributable to the significant broker contract.

Adjusted EPS

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