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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

x      QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended June 30, 2015

OR

o         TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from          to         

Commission file number 001-34892

RHINO RESOURCE PARTNERS LP

(Exact name of registrant as specified in its charter)

(859) 389-6500

(Registrant’s telephone number, including area code)

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.   x Yes  o No

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).  x Yes   o No

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).   o Yes   x No

As of August 5, 2015, 16,705,721 common units and 12,397,000 subordinated units were outstanding.

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Cautionary Note Regarding Forward-Looking Statements

This Quarterly Report on Form 10-Q contains certain “forward-looking statements.” Statements included in this report that are not historical facts, that address activities, events or developments that we expect or anticipate will or may occur in the future, including things such as plans for growth of the business, future capital expenditures, competitive strengths, goals, references to future goals or intentions or other such references are forward-looking statements. These statements can be identified by the use of forward-looking terminology, including “may,” “believe,” “expect,” “anticipate,” “estimate,” “continue,” or similar words. These statements are made by us based on our past experience and our perception of historical trends, current conditions and expected future developments as well as other considerations we believe are reasonable as and when made. Whether actual results and developments in the future will conform to our expectations is subject to numerous risks and uncertainties, many of which are beyond our control. Therefore, actual outcomes and results could materially differ from what is expressed, implied or forecast in these statements.

Any differences could be caused by a number of factors, including, but not limited to: our ability to generate adequate cash flow from operations or to obtain adequate financing to fund our capital expenditures, meet working capital needs and grow our operations; changes in governmental regulation of the mining industry or the electric utility industry; adverse weather conditions and natural disasters; weakness in global economic conditions; decreases in demand for electricity and changes in demand for coal; poor mining conditions resulting from geological conditions or the effects of prior mining; equipment problems at mining locations; the availability of transportation for coal shipments; the availability and costs of key supplies and commodities such as steel, diesel fuel and explosives; the availability and prices of competing electricity generation fuels; our ability to secure or acquire high-quality coal reserves; our ability to successfully diversify our operations into other non-coal natural resources; our ability to find buyers for coal under favorable supply contracts; and volatility and recent declines in the price of our common units and our ability to maintain compliance with the New York Stock Exchange’s (“NYSE”) continued listing requirements. Other factors that could cause our actual results to differ from our projected results are described in (1) Part II, “Item 1A. Risk Factors” and elsewhere in this Form 10-Q, (2) our Annual Report on Form 10-K for the year ended December 31, 2014, (3) our reports and registration statements filed from time to time with the Securities and Exchange Commission and (4) other announcements we make from time to time. In addition, we may be subject to unforeseen risks that may have a materially adverse effect on us.  Accordingly, no assurances can be given that the actual events and results will not be materially different than the anticipated results described in the forward-looking statements.

The forward-looking statements speak only as of the date made, and, other than as required by law, and we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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PART I.—FINANCIAL INFORMATION

Item 1. Financial Statements (Unaudited)

RHINO RESOURCE PARTNERS LP

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL POSITION

(in thousands)

See notes to unaudited condensed consolidated financial statements.

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RHINO RESOURCE PARTNERS LP

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND

COMPREHENSIVE INCOME

(in thousands, except per unit data)

(1) No distributions were paid on the subordinated units for the three and six months ended June 30, 2015 and 2014

See notes to unaudited condensed consolidated financial statements

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RHINO RESOURCE PARTNERS LP

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

See notes to unaudited condensed consolidated financial statements.

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RHINO RESOURCE PARTNERS LP

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2015 AND DECEMBER 31, 2014 AND FOR THE THREE AND SIX MONTHS ENDED

JUNE 30, 2015 AND 2014

1. BASIS OF PRESENTATION AND ORGANIZATION

Basis of Presentation and Principles of Consolidation— The accompanying unaudited interim financial statements include the accounts of Rhino Resource Partners LP and its subsidiaries (the “Partnership”). Intercompany transactions and balances have been eliminated in consolidation.

Unaudited Interim Financial Information—The accompanying unaudited interim financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information. The condensed consolidated statement of financial position as of June 30, 2015, condensed consolidated statements of operations and comprehensive income for the three and six months ended June 30, 2015 and 2014 and the condensed consolidated statements of cash flows for the six months ended June 30, 2015 and 2014 include all adjustments (consisting of normal recurring adjustments) which the Partnership considers necessary for a fair presentation of the financial position, operating results and cash flows for the periods presented. The condensed consolidated statement of financial position as of December 31, 2014 was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (“U.S.”). The Partnership filed its Annual Report on Form 10-K for the year ended December 31, 2014 with the Securities and Exchange Commission (“SEC”), which included all information and notes necessary for such presentation. The results of operations for the interim period are not necessarily indicative of the results to be expected for the year or any future period. These unaudited interim financial statements should be read in conjunction with the audited financial statements included in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2014 filed with the SEC.

Organization—Rhino Resource Partners LP is a Delaware limited partnership formed on April 19, 2010 to acquire Rhino Energy LLC (the “Predecessor” or the “Operating Company”). The Operating Company and its wholly owned subsidiaries produce and market coal from surface and underground mines in Kentucky, Ohio, West Virginia, and Utah. The majority of sales are made to domestic utilities and other coal-related organizations in the United States. In addition to operating coal properties, the Operating Company manages and leases coal properties and collects royalties from such management and leasing activities.

In addition to its coal operations, the Partnership has invested in oil and natural gas properties, mineral rights and other oil and gas infrastructure-related activities that generate revenues for the Partnership.

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2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND GENERAL

Investments in Unconsolidated Affiliates.  Investments in other entities are accounted for using the consolidation, equity method or cost basis depending upon the level of ownership, the Partnership’s ability to exercise significant influence over the operating and financial policies of the investee and whether the Partnership is determined to be the primary beneficiary of a variable interest entity. Equity investments are recorded at original cost and adjusted periodically to recognize the Partnership’s proportionate share of the investees’ net income or losses after the date of investment. Any losses from the Partnership’s equity method investment are absorbed by the Partnership based upon its proportionate ownership percentage. If losses are incurred that exceed the Partnership’s investment in the equity method entity, then the Partnership must continue to record its proportionate share of losses in excess of its investment. Investments are written down only when there is clear evidence that a decline in value that is other than temporary has occurred.

In May 2008, the Operating Company entered into a joint venture, Rhino Eastern LLC (“Rhino Eastern”), with an affiliate of Patriot Coal Corporation (“Patriot”) to acquire the Eagle mining complex. To initially capitalize the joint venture, the Operating Company contributed approximately $16.1 million for a 51% ownership interest in the joint venture. The Partnership accounted for the investment in the joint venture and its results of operations under the equity method. The Partnership considered the operations of this entity to comprise a reporting segment (“Eastern Met”) and has provided additional detail related to this operation in Note 18, “Segment Information.” In January 2015, the Partnership completed a Membership Transfer Agreement (the “Transfer Agreement”) with an affiliate of Patriot that terminated the Rhino Eastern joint venture. Pursuant to the Transfer Agreement, Patriot sold and assigned its 49% membership interest in the Rhino Eastern joint venture to the Partnership and, in consideration of this transfer, Patriot received certain fixed assets, leased equipment and coal reserves associated with the mining area previously operated by the Rhino Eastern joint venture. Patriot also assumed substantially all of the active workforce related to the Eagle mining area that was previously employed by the Rhino Eastern joint venture. The Partnership retained approximately 34 million tons of coal reserves that are not related to the Eagle mining area as well as a prepaid advanced royalty balance. As part of the closing of the Transfer Agreement, the Partnership and Patriot agreed to a dissolution payment based upon a final working capital adjustment calculation as defined in the Transfer Agreement. As of December 31, 2014, the Partnership recorded an impairment charge of approximately $5.9 million related to its investment in the Rhino Eastern joint venture based upon the fair value of the assets received and liabilities assumed in the dissolution of the joint venture compared to the Partnership’s carrying amount of its investment in the joint venture. Refer to Note 17 for further information on the financial statement impact of the Rhino Eastern dissolution completed in January 2015.

In December 2012, the Partnership made an initial investment of approximately $2.0 million in a new joint venture, Muskie Proppant LLC (“Muskie”), with affiliates of Wexford Capital LP (“Wexford Capital”). Muskie was formed to provide sand for fracking operations to drillers in the Utica Shale region and other oil and natural gas basins in the United States. The Partnership accounted for the investment in the joint venture and results of operations under the equity method. The Partnership recorded its proportionate share of the operating losses for

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Muskie for the three and six months ended June 30, 2014 of approximately $77,000 and $118,000, respectively. During the six months ended June 30, 2014, the Partnership contributed additional capital based upon its ownership share to the Muskie joint venture in the amount of $0.2 million. During 2013 the Partnership provided a loan to Muskie totaling approximately $0.2 million which was fully repaid in November 2014 in conjunction with the Partnership’s contribution of its interest in Muskie to Mammoth Energy Partners LP (“Mammoth”), which is discussed below.

In November 2014, the Partnership contributed its investment interest in Muskie to Mammoth in return for a limited partner interest in Mammoth. Mammoth was formed to own various companies that provide services to companies who engage in the exploration and development of North American onshore unconventional oil and natural gas reserves. Mammoth’s companies provide services that include completion and production services, contract land and directional drilling services and remote accommodation services. The non-cash transaction was a contribution of the Partnership’s investment interest in the Muskie entity for an investment interest in Mammoth. Thus, the Partnership determined that the non-cash exchange of the Partnership’s ownership interest in Muskie did not result in any gain or loss. As of June 30, 2015, the Partnership has recorded its investment in Mammoth of $1.9 million as a long-term asset, which the Partnership has accounted for as a cost method investment based upon its ownership percentage. The Partnership has included its investment in Mammoth and its prior investment in Muskie in its Other category for segment reporting purposes.

In September 2014, the Partnership made an initial investment of $5.0 million in a new joint venture, Sturgeon Acquisitions LLC (“Sturgeon”), with affiliates of Wexford Capital and Gulfport Energy (“Gulfport”), a publicly traded company. Sturgeon subsequently acquired 100% of the outstanding equity interests of certain limited liability companies located in Wisconsin that provide frac sand for oil and natural gas drillers in the United States. The Partnership accounts for the investment in the joint venture and results of operations under the equity method. The Partnership recorded its proportionate share of the operating income for Sturgeon for the three and six months ended June 30, 2015 of approximately $0.1 million and $0.3 million, respectively. The Partnership has included the operating activities of Sturgeon in its Other category for segment reporting purposes.

Recently Issued Accounting Standards.  In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). ASU 2014-09 clarifies the principles for recognizing revenue and establishes a common revenue standard for U.S. financial reporting purposes. The guidance in ASU 2014-09 affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (for example, insurance contracts or lease contracts). ASU 2014-09 supersedes the revenue recognition requirements in ASC 605, Revenue Recognition, and most industry-specific accounting guidance. Additionally, ASU 2014-09 supersedes some cost guidance included in ASC 605-35, Revenue Recognition—Construction-Type and Production-Type Contracts. In addition, the existing requirements for the recognition of a gain or loss on the transfer of nonfinancial assets that are not in a contract with a customer (for example, assets within the scope of ASC 360, Property, Plant, and Equipment, and

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intangible assets within the scope of ASC 350, Intangibles—Goodwill and Other) are amended to be consistent with the guidance on recognition and measurement (including the constraint on revenue) in ASU 2014-09. ASU 2014-09 is effective for public entities for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. Early application of ASU 2014-09 is not permitted. In July 2015, the FASB approved to defer the effective date of ASU 2014-09 by one year. ASU 2014-09 will be effective for public entities for annual reporting periods beginning after December 15, 2017 and interim periods therein. The Partnership is currently evaluating the requirements of this new accounting guidance.

In January 2015, the FASB issued ASU 2015-01, “Income Statement-Extraordinary and Unusual Items”. Accounting Standards Codification 225-20, Income Statement—Extraordinary and Unusual Items, required that an entity separately classify, present, and disclose extraordinary events and transactions. ASU 2015-01 eliminates the concept of extraordinary items. The amendments in ASU 2015-01 are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. A reporting entity may apply the amendments prospectively. A reporting entity also may apply the amendments retrospectively to all prior periods presented in the financial statements. Early adoption is permitted provided that the guidance is applied from the beginning of the fiscal year of adoption. The effective date is the same for both public business entities and all other entities. The adoption of ASU 2015-01 on January 1, 2016 is not expected to have a material impact on the Partnership’s financial statements.

In February 2015, the FASB issued ASU 2015-02, “Consolidation”. ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. All legal entities are subject to reevaluation under the revised consolidation model. Specifically, the amendments of ASU 2015-02: a) modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities (VIEs) or voting interest entities, b) eliminate the presumption that a general partner should consolidate a limited partnership, c) affect the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships and d) provide a scope exception from consolidation guidance for reporting entities with interests in legal entities that are required to comply with or operate in accordance with requirements that are similar to those in Rule 2a-7 of the Investment Company Act of 1940 for registered money market funds. ASU 2015-02 is effective for public business entities for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted, including adoption in an interim period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. A reporting entity may apply the amendments in this Update using a modified retrospective approach by recording a cumulative-effect adjustment to equity as of the beginning of the fiscal year of adoption. A reporting entity also may apply the amendments retrospectively. The adoption of ASU 2015-02 on January 1, 2016 is not expected to have a material impact on the Partnership’s financial statements.

In April 2015, the FASB issued ASU 2015-03, “Interest—Imputation of Interest (Subtopic 835-30)-Simplifying the Presentation of Debt Issuance Costs”. ASU 2015-03 requires

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that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. Prior to ASU 2015-03, debt issuance costs have been presented in the balance sheet as a deferred charge, or asset. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this ASU. For public business entities, ASU 2015-03 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption of ASU 2105-03 is permitted for financial statements that have not been previously issued. In addition, ASU 2015-03 requires entities to apply the new guidance on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. The Partnership is currently evaluating the requirements of this new accounting guidance.

3. DISCONTINUED OPERATIONS

Divestiture of Utica Shale Oil and Natural Gas Assets

The Partnership and an affiliate of Wexford Capital participated with Gulfport to acquire interests in a portfolio of oil and natural gas leases in the Utica Shale. As of December 31, 2013, the Partnership had invested approximately $31.1 million for its pro rata interest in the Utica Shale portfolio of oil and gas leases, which consisted of a 5% interest in a total of approximately 152,300 gross acres, or approximately 7,615 net acres. In addition, per the joint operating agreement among the Partnership, Gulfport and an affiliate of Wexford Capital, the Partnership had funded its proportionate share of drilling costs to Gulfport for wells being drilled on the Partnership’s acreage. As of December 31, 2013, the Partnership had funded approximately $23.3 million of drilling costs.

In March 2014, the Partnership completed a purchase and sale agreement (the “Purchase Agreement”) with Gulfport to sell the Partnership’s oil and natural gas properties in the Utica Shale region for approximately $184.0 million (the “Purchase Price”). The Purchase Agreement was effective as of January 1, 2014 and the Purchase Price was adjusted for any unsettled expenditures made and/or proceeds received from the Partnership’s portion of its Utica Shale properties prior to the effective date. At the closing of the Purchase Agreement, the Partnership was immediately due approximately $179.0 million, net of any adjustments described above, and the remaining approximately $5.0 million was scheduled to be paid within approximately 90 days of March 20, 2014, subject to ongoing legal title work related to specific properties. In December 2014, the Partnership settled the remaining $5.0 million due from Gulfport based upon net amounts payable from the Partnership to Gulfport prior to the effective date of the Purchase Agreement as well as amounts due the Partnership related to legal reviews of the properties subject to the Purchase Agreement and other unsettled items due to the Partnership prior to the effective date of the Purchase Agreement. The net effect of this settlement resulted in the Partnership paying Gulfport approximately $46,000 in December 2014. The Partnership recorded a gain of approximately $121.7 million during the six months ended June 30, 2014 related to this sale, which is recorded in Income from discontinued operations in the unaudited condensed consolidated statements of operations and comprehensive income. The gain from the Utica Shale transaction is included in the (Gain) on sale/disposal of assets—net line in the operating activities section of the Partnership’s unaudited condensed consolidated statements of

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cash flows. The proceeds from the Utica Shale transaction are included in the Proceeds from sales of property, plant, and equipment line in the investing activities section of the Partnership’s unaudited condensed consolidated statements of cash flows.

Other Oil and Natural Gas Activities

In January 2014, the Partnership received approximately $8.4 million of net proceeds from the sale by Blackhawk Midstream LLC (“Blackhawk”) of its equity interest in two entities, Ohio Gathering Company, LLC and Ohio Condensate Company, LLC, to Summit Midstream Partners, LLC. As part of the joint operating agreement for the Utica Shale investment discussed above, the Partnership had the right to approximately 5% of the proceeds of the sale by Blackhawk. In February 2015, the Partnership received approximately $0.7 million in additional proceeds from the sale by Blackhawk that had been held in escrow. For the six months ended June 30, 2015 and 2014, the Partnership recorded the $0.7 million and $8.4 million, respectively, in Income from discontinued operations in the unaudited condensed consolidated statements of operations and comprehensive income. The gains from the Blackhawk transaction are included in the (Gain) on sale/disposal of assets—net line in the operating activities section of the Partnership’s unaudited condensed consolidated statements of cash flows. The proceeds from the Blackhawk transaction are included in the Proceeds from sales of property, plant, and equipment line in the investing activities section of the Partnership’s unaudited condensed consolidated statements of cash flows.

4. PREPAID EXPENSES AND OTHER CURRENT ASSETS

Prepaid expenses and other current assets as of June 30, 2015 and December 31, 2014 consisted of the following:

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5. PROPERTY, PLANT AND EQUIPMENT

Property, plant and equipment, including coal properties and mine development and construction costs, as of June 30, 2015 and December 31, 2014 are summarized by major classification as follows:

Depreciation expense for mining and other equipment and related facilities, depletion expense for coal properties and oil and natural gas properties, amortization expense for mine development costs, amortization expense for intangible assets and amortization expense for asset retirement costs for the three and six months ended June 30, 2015 and 2014 were as follows:

Long-Lived Asset Impairments

The Partnership has an oil and natural gas investment of approximately 1,900 net mineral acres in the Cana Woodford region of western Oklahoma. Recently, the Partnership received unsolicited offers from third parties to purchase this oil and natural gas investment. The Partnership has been evaluating these offers in contemplation of a potential sale of these mineral rights. Due to the receipt of these offers and the Partnership’s potential sale of these mineral rights, the Partnership evaluated the appropriate held for sale accounting criteria to determine if the Cana Woodford mineral rights should be classified as held for sale as of June 30, 2015.

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Based on this evaluation, the Partnership determined these mineral rights met the held for sale criteria at June 30, 2015 and, accordingly, these mineral rights were written down to their estimated fair value of $5.8 million. Due to the determination that the mineral rights met the held for sale criteria, the Partnership recorded an impairment charge of approximately $2.2 million for the Cana Woodford mineral rights, which is recorded on the Loss on asset impairments line of the Partnership’s unaudited condensed consolidated statements of operations and statements of cash flows for the three and six months ended June 30, 2015. The $5.8 million estimated fair value of the Cana Woodford mineral rights is recorded on the Non-current assets held for sale line of the Partnership’s unaudited condensed consolidated statements of financial position as of June 30, 2015.

The Partnership had a steam coal surface mine operation in eastern Kentucky (referred to as “Bevins Branch”) in its Central Appalachia segment that was idled during mid-2014 as that location’s contract with its single customer expired at that time. In May 2015, the Partnership finalized a contractual agreement with a third party to assume the Bevins Branch operation. The contractual agreement had the third party assume the Bevins Branch operation where the only financial compensation the Partnership received is a future override royalty and the assumption of the reclamation obligations by the buyer. The closing of the transaction also allows the Partnership to avoid the ongoing maintenance costs of this operation. The Partnership reviewed the Bevins Branch operation as of December 31, 2014 in accordance with the accounting guidance for long-lived asset impairment and recorded total asset impairment and related charges of $8.3 million for the Bevins Branch operation for the year ended December 31, 2014. As of June 30, 2015, the Partnership removed the approximately $2.3 million of remaining assets and any related liabilities that had been previously classified as held for sale on its unaudited condensed consolidated statements of financial position.

6. GOODWILL AND INTANGIBLE ASSETS

Accounting Standards Codification (“ASC”) Topic 350 addresses financial accounting and reporting for goodwill and other intangible assets subsequent to their acquisition. Under the provisions of ASC Topic 350, goodwill and other intangible assets with indefinite useful lives are no longer amortized but instead tested for impairment at least annually.

Intangible assets as of June 30, 2015 consisted of the following:

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Intangible assets as of December 31, 2014 consisted of the following:

The Partnership considers the patent and developed technology intangible assets to have a useful life of seventeen years and the trade name and customer list intangible assets to have a useful life of twenty years. All of the intangible assets are amortized over their useful life on a straight line basis.

Amortization expense for the three and six months ended June 30, 2015 and 2014 is included in the depreciation, depletion and amortization table included in Note 5. The future total amortization expense for each of the five succeeding years related to intangible assets that are currently recorded in the unaudited condensed consolidated statement of financial position is estimated to be as follows at June 30, 2015:

7. OTHER NON-CURRENT ASSETS

Other non-current assets as of June 30, 2015 and December 31, 2014 consisted of the following:

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Debt issuance costs were approximately $11.2 million and $9.1 million as of June 30, 2015 and December 31, 2014, respectively. Accumulated amortization of debt issuance costs were approximately $8.4 million and approximately $7.6 million as of June 30, 2015 and December 31, 2014, respectively. In March 2014, the Partnership entered into a second amendment of its amended and restated senior secured credit facility that reduced the borrowing commitment to $200 million. As part of executing the second amendment to the amended and restated senior secured credit facility, the Operating Company paid a fee of approximately $0.1 million to the lenders in March 2014, which was recorded as an addition to Debt issuance costs. In addition, the Partnership wrote-off approximately $1.1 million of its unamortized debt issuance costs since the second amendment reduced the borrowing commitment under the amended and restated senior secured credit facility.

In April 2015, the Partnership entered into a third amendment of its amended and restated senior secured credit facility that further reduced the borrowing commitment to $100 million. As part of executing the third amendment to the amended and restated senior secured credit facility, the Operating Company paid a fee of approximately $2.1 million to the lenders in April 2015, which was recorded as an addition to Debt issuance costs. The Partnership wrote-off approximately $0.2 million of its remaining unamortized debt issuance costs since the third amendment further reduced the borrowing commitment under the amended and restated senior secured credit facility. See Note 9 for further information on the amendments to the amended and restated senior secured credit facility.

The non-current receivable balance of $14.2 million as of June 30, 2015 and December 31, 2014 consisted of the amount due from the Partnership’s workers’ compensation insurance providers for potential claims that are the primary responsibility of the Partnership, but are covered under the Partnership’s insurance policies. The $14.2 million is also included in the Partnership’s accrued workers’ compensation benefits liability balance, which is included in the non-current liabilities section of the Partnership’s unaudited condensed consolidated statements of financial position. The Partnership presents this amount on a gross asset and liability basis since a right of setoff does not exist per the accounting guidance in ASC Topic 210. This presentation has no impact on the Partnership’s results of operations or cash flows.

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8. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

Accrued expenses and other current liabilities as of June 30, 2015 and December 31, 2014 consisted of the following:

The $0.6 million and $0.5 million accrued for insured litigation claims as of June 30, 2015 and December 31, 2014, respectively, consists of probable and estimable litigation claims that are the primary obligation of the Partnership. The amount accrued for litigation claims is also due from the Partnership’s insurance providers and is included in Accounts receivable, net of allowance for doubtful accounts on the Partnership’s unaudited condensed consolidated statements of financial position. The Partnership presents this amount on a gross asset and liability basis as a right of setoff does not exist per the accounting guidance in ASC Topic 210. This presentation has no impact on the Partnership’s results of operations or cash flows.

The increase in the amount of other accrued liabilities as of June 30, 2015 compared to December 31, 2014 primarily relates to liabilities accrued as part of the Rhino Eastern dissolution completed in January 2015, which is discussed further in Notes 2 and 17.

9. DEBT

Debt as of June 30, 2015 and December 31, 2014 consisted of the following:

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Senior Secured Credit Facility with PNC Bank, N.A.—On July 29, 2011, the Operating Company and the Partnership, as a guarantor, executed an amended and restated senior secured credit facility with PNC Bank, N.A., as administrative agent, and a group of lenders, which are parties thereto. The maximum availability under the amended and restated credit facility was $300.0 million, with a one-time option to increase the availability by an amount not to exceed $50.0 million. Of the $300.0 million, $75.0 million was available for letters of credit. As described below, in April 2015 and March 2014 the amended and restated credit facility was amended and the borrowing commitment under the facility was reduced to $100 million, with the amount available for letters of credit reduced to $50 million. Borrowings under the facility bear interest, which varies depending upon the levels of certain financial ratios. As part of the agreement, the Operating Company is required to pay a commitment fee on the unused portion of the borrowing availability that also varies depending upon the levels of certain financial ratios. Borrowings on the amended and restated senior secured credit facility are collateralized by all of the unsecured assets of the Partnership. The amended and restated senior secured credit facility requires the Partnership to maintain certain minimum financial ratios and contains certain restrictive provisions, including among others, restrictions on making loans, investments and advances, incurring additional indebtedness, guaranteeing indebtedness, creating liens, and selling or assigning stock. The Partnership was in compliance with all covenants contained in the amended and restated senior secured credit facility as of and for the period ended June 30, 2015. The amended and restated senior secured credit facility was previously set to expire in July 2016, but the term was extended to July 2017 pursuant to the third amendment of the facility, which is described further below.

In March 2014, the Partnership entered into a second amendment of its amended and restated senior secured credit facility with PNC Bank, N.A., as administrative agent, and a group of lenders, which are parties thereto. This second amendment permitted the Partnership to sell certain assets to Gulfport, as described in Note 3, which previously constituted a portion of the collateral under the amended and restated senior secured credit facility. This second amendment also reduced the borrowing commitment under the amended and restated senior secured credit facility to a maximum of $200 million and altered the maximum leverage ratio. In addition, the second amendment adjusted the maximum investments (other than by the Partnership) in hydrocarbons, hydrocarbon interests and assets and activities related to hydrocarbons, in each case, excluding coal, in an aggregate amount not to exceed $50 million. As part of executing the second amendment to the amended and restated senior secured credit facility, the Operating Company paid a fee of approximately $0.1 million to the lenders in March 2014, which was recorded in Debt issuance costs in Other non-current assets on the Partnership’s unaudited condensed consolidated statements of financial position. In addition, the Partnership recorded a non-cash charge of approximately $1.1 million to write-off a portion of its unamortized debt issuance costs since the second amendment reduced the borrowing commitment under the amended and restated senior secured credit facility, which was recorded in Interest expense on the Partnership’s unaudited condensed consolidated statements of operations and comprehensive income.

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In April 2015, the Partnership entered into a third amendment of its amended and restated senior secured credit facility. The third amendment extended the expiration date of the amended and restated credit agreement to July 2017. The extension is contingent upon the Partnership’s leverage ratio being less than or equal to 2.75 to 1.0 and the Partnership having liquidity greater than or equal to $15 million for either quarter ending December 31, 2015 or March 31, 2016.  If both of these conditions are not satisfied for one of the periods, the expiration date of the amended and restated credit agreement will revert to July 2016. The third amendment also reduced the borrowing commitment under the credit facility to a maximum of $100 million and reduced the amount available for letters of credit to $50 million. The third amendment also provided that the disposition of any assets by the Partnership consisting of net cash proceeds up to an aggregate $35 million shall reduce the total commitment under the facility on a dollar-for-dollar basis by up to a total of $10 million, and any dispositions of assets in excess of $35 million in the aggregate shall reduce the commitment under the facility on a dollar-for-dollar basis. The third amendment changed the maximum leverage ratio to 3.75 to 1.0 through September 30, 2015. The maximum leverage ratio decreases to 3.5 to 1.0 from October 1, 2015 through December 31, 2015 and then decreases to 3.25 to 1.0 from January 1, 2016 through March 31, 2016. The maximum leverage ratio decreases to 3.0 to 1.0 after March 31, 2016. Notwithstanding the above, the leverage ratio shall be reduced by 0.25 for every $10 million of gross cash proceeds received by the Partnership from the sale of any assets; provided, however, that in no event shall the maximum permitted leverage ratio be reduced below 3.00 to 1.0. The third amendment limited the Partnership’s quarterly distributions to a maximum of $0.035 per unit unless (i) the pro forma leverage ratio of the Partnership, immediately prior to and after giving effect to such distribution, is less than or equal to 3.0 to 1.0 and (ii) the amount of borrowings available under the credit facility, immediately prior to and after giving effect to such distribution, is at least $20 million. In addition, the third amendment removed the interest coverage ratio covenant and replaced it with a minimum fixed charge coverage ratio, which consisted of the ratio of consolidated EBITDA minus maintenance capital expenditures to fixed charges. Fixed charges are defined in the third amendment to include the sum of cash interest expense, scheduled principal installments on indebtedness (as adjusted for prepayments), dividends and distributions. Commencing with the quarter ending September 30, 2015, the fixed charge coverage ratio for the trailing four quarters must be a minimum of 1.1 to 1.0. The third amendment also limited any investments made by the Partnership, including investments in hydrocarbons, to $10 million provided that the leverage ratio is less than or equal to 3.0 to 1.0 and the borrowers’ available liquidity is at least $20 million. The third amendment does not permit the Partnership to issue any new equity of the Partnership unless the proceeds of such equity issuance are used to reduce the outstanding borrowings under the facility. Issuances of equity under the Partnership’s long-term incentive plan are excluded from this requirement. The third amendment limited the amount of the Partnership’s capital expenditures to $20.0 million for fiscal year 2015 and limited capital expenditures to $27.5 million for each fiscal year after 2015. However, to the extent that capital expenditures for any fiscal year are less than indicated above, the Partnership may increase the following year’s capital expenditures by the lesser of such unused amount or $5.0 million. As part of executing the third amendment to the amended and restated senior secured credit facility, the Operating Company paid a fee of approximately $2.1 million to the lenders in April 2015, which was recorded in Debt issuance costs in Other non-current assets on the Partnership’s unaudited condensed consolidated statements of financial position. In addition, the Partnership recorded a non-cash charge of approximately $0.2 million

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to write-off a portion of its unamortized debt issuance costs since the third amendment reduced the borrowing commitment under the amended and restated senior secured credit facility, which was recorded in Interest expense on the Partnership’s unaudited condensed consolidated statements of operations and comprehensive income.

At June 30, 2015, the Operating Company had borrowings outstanding (excluding letters of credit) of $52.6 million at a variable interest rate of LIBOR plus 4.50% (4.69% at June 30, 2015). In addition, the Operating Company had outstanding letters of credit of approximately $16.0 million at a fixed interest rate of 4.50% at June 30, 2015. Based upon a maximum borrowing capacity of 3.75 times a trailing twelve-month EBITDA calculation (as defined in the credit agreement), the Operating Company had available borrowing capacity of approximately $8.6 million at June 30, 2015.

10. ASSET RETIREMENT OBLIGATIONS

The changes in asset retirement obligations for the six months ended June 30, 2015 and the year ended December 31, 2014 are as follows:

(1)    The ($2.3) million adjustment for the year ended December 31, 2014 primarily relates to the transfer of certain mining permits to a third party that relieved the Partnership of the asset retirement obligations related to these permits.

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11. EMPLOYEE BENEFITS

In conjunction with the acquisition of the coal operations of American Electric Power on April 16, 2004, the Operating Company acquired a postretirement benefit plan providing healthcare to eligible employees at its Hopedale operations. The Partnership has no other postretirement plans.

Net periodic benefit cost for the three and six months ended June 30, 2015 and 2014 are as follows: