-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 BMnhMHPZVerB2STMJdgoQAe6AteNcT7dyA/NRMCJBVR8Ko6uH/4kKJy742w4SKVa
 7bEhX0m2Ljy7tzEexQ7vvw==

<SEC-DOCUMENT>0000950134-05-024007.txt : 20051230
<SEC-HEADER>0000950134-05-024007.hdr.sgml : 20051230
<ACCEPTANCE-DATETIME>20051230162841
ACCESSION NUMBER:		0000950134-05-024007
CONFORMED SUBMISSION TYPE:	SC 13D/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20051230
DATE AS OF CHANGE:		20051230

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			HALLADOR PETROLEUM CO
		CENTRAL INDEX KEY:			0000788965
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				841014610
		STATE OF INCORPORATION:			CO
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13D/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-37955
		FILM NUMBER:		051294950

	BUSINESS ADDRESS:	
		STREET 1:		1660 LINCOLN ST STE 2700
		CITY:			DENVER
		STATE:			CO
		ZIP:			80264
		BUSINESS PHONE:		3038395505

	MAIL ADDRESS:	
		STREET 1:		1660 LINCOLN STREET
		STREET 2:		SUITE 2700
		CITY:			DENVER
		STATE:			CO
		ZIP:			80264

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	KIMBARK OIL & GAS CO /CO/
		DATE OF NAME CHANGE:	19900102

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	KIMBARK INC
		DATE OF NAME CHANGE:	19860624

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			YORKTOWN ENERGY PARTNERS II LP
		CENTRAL INDEX KEY:			0001050354

	FILING VALUES:
		FORM TYPE:		SC 13D/A

	BUSINESS ADDRESS:	
		STREET 1:		535 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		2129067000

	MAIL ADDRESS:	
		STREET 1:		535 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13D/A
<SEQUENCE>1
<FILENAME>d31684asc13dza.htm
<DESCRIPTION>AMENDMENT TO SCHEDULE 13D
<TEXT>
<HTML>
<HEAD>
<TITLE>sc13dza</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF">
<!-- PAGEBREAK -->
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>
<DIV style="font-family: 'Times New Roman',Times,serif">


<DIV align="right">
<TABLE style="font-size: 12pt" cellspacing="0" border="0" cellpadding="0"
width="15%">
<!-- Begin Table Head -->
<TR valign="bottom">
<TD width="1%">&nbsp;</TD>
<TD width="98%">&nbsp;</TD>
<TD width="1%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
<TD width="1%" style="border-left: 1px solid #000000; border-top: 1px solid
#000000; border-bottom: 1px solid #000000">&nbsp;</TD>
<TD align="center" valign="top" style="border-top: 1px solid #000000;
border-bottom: 1px solid #000000"><DIV style="margin-left:0px;
text-indent:-0px">OMB APPROVAL</DIV></TD>
<TD width="1%" style="border-right: 1px solid #000000; border-top: 1px solid
#000000; border-bottom: 1px solid #000000">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD width="1%" style="border-left: 1px solid #000000">&nbsp;</TD>
<TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">OMB Number:
3235-0145</DIV></TD>
<TD width="1%" style="border-right: 1px solid #000000">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD width="1%" style="border-left: 1px solid #000000">&nbsp;</TD>
<TD valign="top" nowrap><DIV style="margin-left:0px; text-indent:-0px">Expires:
December&nbsp;31, 2005</DIV>
</TD>
<TD width="1%" style="border-right: 1px solid #000000">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD width="1%" style="border-left: 1px solid #000000">&nbsp;</TD>
<TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Estimated
average burden hours per response...15</DIV></TD>
<TD width="1%" style="border-right: 1px solid #000000">&nbsp;</TD>
</TR>
<TR style="font-size: 1px" valign="bottom">
<TD nowrap align="left" colspan="3" style="border-top: 1px solid
#000000">&nbsp;</TD>
</TR>

<!-- End Table Body -->
</TABLE>
</DIV>

<DIV style="width: 100%; border-bottom: 2pt solid black; font-size:
1pt">&nbsp;</DIV>
<DIV style="width: 100%; border-bottom: 1pt solid black; font-size:
1pt">&nbsp;</DIV>


<P align="center" style="font-size: 14pt"><B>UNITED STATES<BR>
SECURITIES AND EXCHANGE COMMISSION</B>

<DIV align="center" style="font-size: 12pt"><B>Washington, D.C. 20549</B>
</DIV>

<P align="center" style="font-size: 18pt"><B>SCHEDULE 13D</B>


<P align="center" style="font-size: 12pt"><B>Under the Securities Exchange Act
of 1934<BR>
(Amendment No.&nbsp;1&nbsp;)*</B>


<DIV align="center">
<DIV style="font-size: 24pt; margin-top: 16pt; width: 100%; border-bottom: 1px
solid #000000">HALLADOR PETROLEUM COMPANY</DIV>
</DIV>


<DIV align="center" style="font-size: 10pt">(Name of Issuer)
</DIV>


<DIV align="center">
<DIV style="font-size: 10pt; margin-top: 16pt; width: 100%; border-bottom: 1px
solid #000000">Common Stock, par value $.01</DIV>
</DIV>

<DIV align="center" style="font-size: 10pt">(Title of Class of Securities)
</DIV>


<DIV align="center">
<DIV style="font-size: 10pt; margin-top: 16pt; width: 100%; border-bottom: 1px
solid #000000">406092205</DIV>
</DIV>

<DIV align="center" style="font-size: 10pt">(CUSIP Number)
</DIV>


<DIV align="center">
<DIV style="font-size: 10pt; margin-top: 16pt; width: 100%; border-bottom: 1px
solid #000000">Peter A. Leidel<BR>410 Park Avenue, 19th Floor<BR>New York, New
York 10022<BR></DIV>
</DIV>


<DIV align="center" style="font-size: 10pt">(Name, Address and Telephone Number
of Person Authorized to<BR>
Receive Notices and Communications)
</DIV>


<DIV align="center">
<DIV style="font-size: 10pt; margin-top: 16pt; width: 100%; border-bottom: 1px
solid #000000">December 20, 2005</DIV>
</DIV>

<DIV align="center" style="font-size: 10pt">(Date of Event Which Requires Filing
of this Statement)
</DIV>

<P align="left" style="font-size: 10pt">If the filing person has previously
filed a statement on Schedule&nbsp;13G to report the acquisition that is the
subject of this Schedule&nbsp;13D, and is filing this schedule because of
&#167;&#167;240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.
<FONT face="wingdings" size="2">&#111;</FONT>

<P align="left" style="font-size: 10pt"><B>Note: </B>Schedules filed in paper
format shall include a signed original and five copies of the schedule,
including all exhibits. See &#167;240.13d-7 for other parties to whom copies are
to be sent.

<P align="left" style="font-size: 10pt">* The remainder of this cover page shall
be filled out for a reporting person&#146;s initial filing on this form with
respect to the subject class of securities, and for any subsequent amendment
containing information which would alter disclosures provided in a prior cover
page.

<P align="left" style="font-size: 10pt">The information required on the
remainder of this cover page shall not be deemed to be &#147;filed&#148; for the
purpose of Section 18 of the Securities Exchange Act of 1934 (&#147;Act&#148;)
or otherwise subject to the liabilities of that section of the Act but shall be
subject to all other provisions of the Act (however, see the Notes).

<P align="left" style="font-size: 10pt"><B>Persons who respond to the collection
of information contained in this form are not required to respond unless the
form displays a currently valid OMB control number.</B>


<DIV style="width: 100%; border-bottom: 1pt solid black; margin-top: 10pt;
font-size: 1pt">&nbsp;</DIV>
<DIV style="width: 100%; border-bottom: 2pt solid black; font-size:
1pt">&nbsp;</DIV>

<P align="center" style="font-size: 10pt">Page 1 of 4
</DIV>



<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0"
width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
<TD width="1%">&nbsp;</TD>
<TD width="1%">&nbsp;</TD>
<TD width="20%">&nbsp;</TD>
<TD width="55%">&nbsp;</TD>
<TD width="1%">&nbsp;</TD>
<TD width="1%">&nbsp;</TD>
<TD width="9%">&nbsp;</TD>
<TD width="1%">&nbsp;</TD>
<TD width="1%">&nbsp;</TD>
<TD width="1%">&nbsp;</TD>
<TD width="9%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->


<TR valign="bottom">
<TD valign="top" nowrap><DIV style="margin-left:0px; text-indent:-0px">CUSIP
No.</DIV></TD>
<TD>&nbsp;</TD>
<TD align="center" valign="top"><DIV style="border: 1px solid
#000000">406092205&nbsp;</DIV></TD>
<TD>&nbsp;</TD>
<TD align="left" valign="top">Page</TD>
<TD>&nbsp;</TD>
<TD align="center" valign="top"><DIV style="border: 1px solid
#000000">2&nbsp;</DIV></TD>
<TD>&nbsp;</TD>
<TD align="left" valign="top">of&nbsp;</TD>
<TD>&nbsp;</TD>
<TD align="center" valign="top"><DIV style="border: 1px solid
#000000">4&nbsp;</DIV></TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>

<P>&nbsp;<DIV style="width: 100%; border: 1px solid black"><DIV align="center">

<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="1"
width="100%">
<!-- Begin Table Head --><TR style="font-size: 1px">
<TD width="5%">&nbsp;</TD>
<TD width="1%" style="border-left: 1px solid #000000">&nbsp;</TD>
<TD width="5%">&nbsp;</TD>
<TD width="5%">&nbsp;</TD>
<TD width="1%">&nbsp;</TD>
<TD width="83%">&nbsp;</TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>1</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">NAMES OF REPORTING PERSONS:<BR>
<BR>
YORKTOWN ENERGY PARTNERS II, L.P.</TD>
</TR>
<TR valign="bottom"> <TD style="border-left: 1px solid #000000">&nbsp;</TD> <TD
colspan="4" align="left">&nbsp;</TD> </TR> <TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS
(ENTITIES ONLY):<BR>&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left"></TD>
</TR>

<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>2</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
(SEE INSTRUCTIONS):<BR><BR></TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">(a)&nbsp;&nbsp;&nbsp;<FONT face="wingdings"
size="2">&#111;</FONT>&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">(b)&nbsp;&nbsp;&nbsp;<FONT face="wingdings"
size="2">&#111;</FONT>&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>3</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">SEC USE ONLY:</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">&nbsp;</TD>
</TR>

<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>4</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">SOURCE OF FUNDS (SEE INSTRUCTIONS):</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="11" align="left">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="11" align="left">WC</TD>
</TR>

<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>5</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS
REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e):</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left"><FONT face="wingdings" size="2">&#111;</FONT></TD>
</TR>

<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>6</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">CITIZENSHIP OR PLACE OF ORGANIZATION:</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">Delaware
</TD>
</TR>

<TR style="font-size: 1px">
<TD colspan="3" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000; border-left: 1px solid
#000000; border-right: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD align="center" colspan="3">&nbsp;</TD>
<TD valign="middle" align="center" rowspan="3" style="border-left: 1px solid
#000000; border-right: 1px solid #000000"><FONT style="font-size:
18pt"><B>7</B></FONT></TD>
<TD>&nbsp;</TD>
<TD align="left">SOLE VOTING POWER:</TD>
</TR>
<TR valign="bottom">
<TD align="center" colspan="3">&nbsp;</TD>
<TD>&nbsp;</TD>
<TD>&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD align="center" colspan="3">NUMBER OF</TD>
<TD>&nbsp;</TD>
<TD align="left">0</TD>
</TR>

<TR style="font-size: 1px">
<TD colspan="3">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000; border-left: 1px solid
#000000; border-right: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD align="center" colspan="3">SHARES</TD>
<TD valign="middle" align="center" rowspan="3" style="border-left: 1px solid
#000000; border-right: 1px solid #000000"><FONT style="font-size:
18pt"><B>8</B></FONT></TD>
<TD>&nbsp;</TD>
<TD align="left">SHARED VOTING POWER:</TD>
</TR>
<TR valign="bottom">
<TD align="center" colspan="3">BENEFICIALLY</TD>
<TD>&nbsp;</TD>
<TD>&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD align="center" colspan="3">OWNED BY</TD>
<TD>&nbsp;</TD>
<TD>0</TD>
</TR>

<TR style="font-size: 1px">
<TD colspan="3">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000; border-left: 1px solid
#000000; border-right: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>


<TR valign="bottom">
<TD align="center" colspan="3">EACH</TD>
<TD valign="middle" align="center" rowspan="3" style="border-left: 1px solid
#000000; border-right: 1px solid #000000"><FONT style="font-size:
18pt"><B>9</B></FONT></TD>
<TD>&nbsp;</TD>
<TD align="left">SOLE DISPOSITIVE POWER:</TD>
</TR>
<TR valign="bottom">
<TD align="center" colspan="3">REPORTING</TD>
<TD>&nbsp;</TD>
<TD>&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD align="center" colspan="3">PERSON</TD>
<TD>&nbsp;</TD>
<TD align="left">0</TD>
</TR>
<TR style="font-size: 1px">
<TD colspan="3">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000; border-left: 1px solid
#000000; border-right: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
<TD align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD align="center" colspan="3">WITH</TD>
<TD valign="middle" align="center" rowspan="3" style="border-left: 1px solid
#000000; border-right: 1px solid #000000"><FONT style="font-size:
18pt"><B>10</B></FONT></TD>
<TD>&nbsp;</TD>
<TD align="left">SHARED DISPOSITIVE POWER:</TD>
</TR>
<TR valign="bottom">
<TD align="center" colspan="3">&nbsp;</TD>
<TD>&nbsp;</TD>
<TD>&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD align="center" colspan="3">&nbsp;</TD>
<TD>&nbsp;</TD>
<TD align="left">0</TD>
</TR>
<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>11</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
REPORTING PERSON:</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">0</TD>
</TR>

<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>12</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">CHECK IF THE AGGREGATE AMOUNT IN ROW
(11)&nbsp;EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS):</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left"><FONT face="wingdings" size="2">&#111;</FONT>
</TD>
</TR>

<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>13</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW
(11):</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">0&#37;</TD>
</TR>

<TR style="font-size: 1px">
<TD style="border-top: 1px solid #000000">&nbsp;</TD>
<TD style="border-left: 1px solid #000000; border-top: 1px solid
#000000">&nbsp;</TD>
<TD colspan="4" align="left" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>

<TR valign="bottom">
<TD valign="middle" align="center" rowspan="3"><FONT style="font-size:
18pt"><B>14</B></FONT></TD>
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">&nbsp;</TD>
</TR>
<TR valign="bottom">
<TD style="border-left: 1px solid #000000">&nbsp;</TD>
<TD colspan="4" align="left">PN</TD>
</TR>
<!-- End Table Body --></TABLE>
</DIV>
</DIV>


<P align="center" style="font-size: 10pt">&nbsp;
</DIV>
<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>
<DIV style="font-family: 'Times New Roman',Times,serif">

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;1.</B>&nbsp;&nbsp; <B>SECURITY AND ISSUER.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This Amendment No.&nbsp;1 amends the Schedule&nbsp;13D filed on February&nbsp;27, 1998 relating to the common
stock (the &#147;Common Stock&#148;) of Hallador Petroleum Company (the &#147;Company&#148;) whose principal executive
offices are located at 1660 Lincoln Street, Suite&nbsp;2700, Denver, CO 80264.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;2.&nbsp;&nbsp; IDENTITY AND BACKGROUND.</B>
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This statement is filed by Yorktown Energy Partners II, L.P., a Delaware limited partnership
(&#147;Yorktown&#148;). Yorktown&#146;s principal office and business address is 410 Park Avenue, 19<SUP style="font-size: 85%; vertical-align: text-top">th</SUP>
Floor, New York, New York, 10022. The principal business of Yorktown is investing in equity
securities of energy investments.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Yorktown has not, during the last five years, been convicted in a criminal proceeding
(excluding traffic violations or similar misdemeanors).
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Yorktown has not, during the last five years, been a party to a civil proceeding of a judicial
or administrative body of competent jurisdiction and as a result of such proceeding was or is
subject to a judgment, decree or final order enjoining future violations of, or prohibiting or
mandating activities subject to, federal or state securities laws or finding any violation with
respect to such laws.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;3.&nbsp;&nbsp; SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;N/A
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;4.&nbsp;&nbsp; PURPOSE OF TRANSACTION.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;N/A
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;5.&nbsp;&nbsp; INTEREST IN SECURITIES OF THE ISSUER.</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a)&nbsp;&nbsp;&nbsp;&nbsp;As of December&nbsp;20, 2005, Yorktown did not own any shares of common stock of the Company.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b)&nbsp;&nbsp;&nbsp;&nbsp;N/A.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c)&nbsp;&nbsp;&nbsp;&nbsp;Yorktown sold 1,936,725 shares to Yorktown Energy Partners VI, L.P., 136,710 shares to
Lubar Equity Fund, LLC, 136,710 shares to Tecovas Partners V, L.P. and 68,355 shares to Murchison
Capital Partners, L.P. for $2.20 per share on December&nbsp;20, 2005.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d)&nbsp;&nbsp;&nbsp;&nbsp;N/A
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e)&nbsp;&nbsp;&nbsp;&nbsp;N/A.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;6.&nbsp;&nbsp; CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO SECURITIES OF THE ISSUER.</B>
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">None.
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Item&nbsp;7.&nbsp;&nbsp; MATERIAL TO BE FILED AS EXHIBITS</B>
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">None.
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 18pt">Page 3 of 4
</DIV>



<P align="center" style="font-size: 10pt">&nbsp;
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">




<DIV align="center" style="font-size: 10pt; margin-top: 18pt">SIGNATURES
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">After reasonable inquiry and to the best of my knowledge and belief, I certify that the information
set forth in this statement is true, complete and correct.
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 12pt">Date: December&nbsp;30, 2005
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 12pt">YORKTOWN ENERGY PARTNERS II, L.P.
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="4%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="95%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">By:
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Yorktown II Company LLC<br>
Its general partner</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="30%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="65%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">

<TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">By:&nbsp;&nbsp;&nbsp;&nbsp;/s/  W. Howard Keenan
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD align="right" valign="top"><div style="border-top: 1px solid #000000; width: 91%">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">

<TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Name:&nbsp;&nbsp;&nbsp;&nbsp;W. Howard Keenan</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD align="right" valign="top"><div style="border-top: 1px solid #000000; width: 85%">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">

<TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Title:&nbsp;&nbsp;&nbsp;&nbsp;Member
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD align="right" valign="top"><div style="border-top: 1px solid #000000; width: 87%">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<P align="center" style="font-size: 10pt">Page 4 of 4
</DIV>

</BODY>
</HTML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
