Exhibit 99.1
 
  
 Re:
    
    Evaluation SummaryPostRock Energy Corporation InterestsProved, Probable and Possible ReservesAs of December 31, 2009




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Recombined Methodology.
 Recombined NYMEX Methodology.




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CAWLEY, GILLESPIE & ASSOCIATES, INC.




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Appendix
  SEC Scenario
 Proved
    
    ProvedDeveloped
    
    Developed
    
    ProvedProducing
    
    Non-Producing
    
    Undeveloped
    
    Proved
    
    Probable
    
    PossibleNet ReservesOil/Condensate
    
    -Mbbl
    
    
    759.1
    
    
    
    26.3
    
    
    
    38.7
    
    
    
    824.0
    
    
    
    8.3
    
    
    
    0.0Gas
    
    -MMcf
    
    
    56,391.4
    
    
    
    5,743.8
    
    
    
    7,739.3
    
    
    
    69,874.6
    
    
    
    4,439.2
    
    
    
    9,125.6RevenueOil/Condensate
    
    -M$
    
    
    44,731.1
    
    
    
    1,610.9
    
    
    
    2,386.5
    
    
    
    48,728.5
    
    
    
    458.1
    
    
    
    0.0Gas
    
    -M$
    
    
    202,516.8
    
    
    
    20,819.1
    
    
    
    39,766.5
    
    
    
    263,102.5
    
    
    
    22,895.2
    
    
    
    47,066.1Severance and
Ad Valorem Taxes
    
    -M$
    
    
    15,589.5
    
    
    
    1,477.9
    
    
    
    2,292.7
    
    
    
    19,360.1
    
    
    
    1,277.7
    
    
    
    2,559.5Operating Expenses
    
    -M$
    
    
    70,283.7
    
    
    
    5,730.6
    
    
    
    12,742.4
    
    
    
    88,756.6
    
    
    
    8,011.2
    
    
    
    12,609.3Gathering Expenses
    
    -M$
    
    
    85,218.3
    
    
    
    8,199.1
    
    
    
    1,110.7
    
    
    
    94,528.1
    
    
    
    549.0
    
    
    
    1,117.3Investments
    
    -M$
    
    
    0.0
    
    
    
    2,067.9
    
    
    
    15,330.3
    
    
    
    17,398.2
    
    
    
    8,738.5
    
    
    
    18,500.0Operating Income (BFIT)
    
    -M$
    
    
    76,156.5
    
    
    
    4,954.6
    
    
    
    10,676.9
    
    
    
    91,788.0
    
    
    
    4,776.8
    
    
    
    12,280.0Discounted @ 10%
    
    -M$
    
    
    47,131.6
    
    
    
    2,663.6
    
    
    
    764.0
    
    
    
    50,559.2
    
    
    
    435.0
    
    
    
    139.2
 Recombined Methodology
 Proved
    
    ProvedDeveloped
    
    Developed
    
    ProvedProducing
    
    Non-Producing
    
    Undeveloped
    
    Proved
    
    Probable
    
    PossibleNet ReservesOil/Condensate
    
    -Mbbl
    
    
    759.9
    
    
    
    26.3
    
    
    
    51.3
    
    
    
    837.5
    
    
    
    330.5
    
    
    
    0.0Gas
    
    -MMcf
    
    
    88,859.4
    
    
    
    7,626.1
    
    
    
    8,789.2
    
    
    
    105,274.6
    
    
    
    31,755.4
    
    
    
    9,125.8RevenueOil/Condensate
    
    -M$
    
    
    44,779.4
    
    
    
    1,611.4
    
    
    
    3,081.4
    
    
    
    49,472.2
    
    
    
    18,200.6
    
    
    
    0.0Gas
    
    -M$
    
    
    309,499.6
    
    
    
    26,975.0
    
    
    
    45,151.0
    
    
    
    381,625.5
    
    
    
    163,029.1
    
    
    
    47,066.1Severance and
Ad Valorem Taxes
    
    -M$
    
    
    23,035.8
    
    
    
    1,915.0
    
    
    
    2,624.2
    
    
    
    27,575.0
    
    
    
    9,885.1
    
    
    
    2,559.5Operating Expenses
    
    -M$
    
    
    127,289.2
    
    
    
    8,585.7
    
    
    
    14,161.7
    
    
    
    150,036.6
    
    
    
    25,675.7
    
    
    
    12,609.3Gathering Expenses
    
    -M$
    
    
    64,667.4
    
    
    
    5,425.7
    
    
    
    1,168.2
    
    
    
    71,261.3
    
    
    
    4,179.1
    
    
    
    1,117.3Investments
    
    -M$
    
    
    0.0
    
    
    
    4,732.0
    
    
    
    17,470.3
    
    
    
    22,202.3
    
    
    
    67,881.7
    
    
    
    18,500.0Operating Income (BFIT)
    
    -M$
    
    
    139,286.5
    
    
    
    7,928.0
    
    
    
    12,808.0
    
    
    
    160,022.5
    
    
    
    73,608.1
    
    
    
    12,280.0Discounted @ 10%
    
    -M$
    
    
    95,237.5
    
    
    
    3,835.2
    
    
    
    828.7
    
    
    
    99,901.4
    
    
    
    2,119.6
    
    
    
    139.2




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NYMEX Recombined Methodology
 Proved
    
    ProvedDeveloped
    
    Developed
    
    ProvedProducing
    
    Non-Producing
    
    Undeveloped
    
    Proved
    
    Probable
    
    PossibleNet ReservesOil/Condensate
    
    -Mbbl
    
    
    832.7
    
    
    
    36.7
    
    
    
    51.3
    
    
    
    920.8
    
    
    
    330.6
    
    
    
    65.4Gas
    
    -MMcf
    
    
    130,183.7
    
    
    
    28,688.7
    
    
    
    58,433.8
    
    
    
    217,306.4
    
    
    
    57,419.2
    
    
    
    94,850.4RevenueOil/Condensate
    
    -M$
    
    
    69,227.3
    
    
    
    3,089.3
    
    
    
    4,322.1
    
    
    
    76,638.7
    
    
    
    26,592.6
    
    
    
    5,283.4Gas
    
    -M$
    
    
    866,408.9
    
    
    
    200,296.0
    
    
    
    410,533.1
    
    
    
    1,477,237.9
    
    
    
    454,833.6
    
    
    
    671,815.5Severance and
Ad Valorem Taxes
    
    -M$
    
    
    62,412.4
    
    
    
    13,641.8
    
    
    
    27,671.5
    
    
    
    103,725.7
    
    
    
    28,909.8
    
    
    
    44,034.4Operating Expenses
    
    -M$
    
    
    275,648.4
    
    
    
    41,142.7
    
    
    
    80,756.4
    
    
    
    397,547.7
    
    
    
    63,360.9
    
    
    
    105,056.6Gathering Expenses
    
    -M$
    
    
    97,189.0
    
    
    
    19,930.7
    
    
    
    40,265.5
    
    
    
    157,385.2
    
    
    
    23,521.9
    
    
    
    65,474.1Investments
    
    -M$
    
    
    40.0
    
    
    
    27,603.0
    
    
    
    110,697.5
    
    
    
    138,340.5
    
    
    
    113,464.2
    
    
    
    159,260.0Operating Income (BFIT)
    
    -M$
    
    
    500,346.3
    
    
    
    101,067.1
    
    
    
    155,464.2
    
    
    
    756,877.7
    
    
    
    252,169.3
    
    
    
    303,273.7Discounted @ 10%
    
    -M$
    
    
    325,833.8
    
    
    
    49,538.8
    
    
    
    56,527.9
    
    
    
    431,900.8
    
    
    
    63,437.2
    
    
    
    75,996.3