PROMISSORY NOTE

$9,000,000.                                                          May 5, 1998



                  FOR VALUE RECEIVED, the undersigned, COVOL TECHNOLOGIES, INC.,
a Delaware corporation ("Covol") hereby  unconditionally  promises to pay to the
order of MOUNTAINEER  SYNFUEL,  L.L.C.,  a Delaware  limited  liability  company
("Mountaineer"),  in  lawful  money  of the  United  States  and in  immediately
available funds, the principal amount of $9,000,000,  or, if less, the aggregate
amounts loaned by Mountaineer to Covol as provided in Section 11.10 of the Asset
Purchase  Agreement dated May 5, 1998 between Covol and Mountaineer (the "APA"),
which sum shall be due and payable and paid to Mountaineer on the earlier of the
Closing Date (as defined in the APA) or January 1, 1999.

                  The holder of this promissory note is authorized to record, on
the  schedule  annexed  hereto and made a part hereof,  or on other  appropriate
records of Mountaineer, the date and amount of each amount loaned by Mountaineer
to Covol under  Section  11.10 of the APA;  provided,  however,  that failure by
Mountaineer  to make any  recordation  or other error therein shall not limit or
otherwise affect the obligations of Covol hereunder. This promissory note is the
promissory note referred to in Section 11.10 of the APA.

                  The obligation of Covol is absolute and  unconditional  to pay
the  principal of this  promissory  note at the offices of  Mountaineer,  at the
time, and in the currency herein  prescribed.  Covol waives any and all right to
assert any defense (other than performance hereunder),  set-off, counterclaim or
crossclaim of any nature  whatsoever with respect to this promissory note or the
obligations  of  Covol  hereunder  in  any  action  or  proceeding   brought  by
Mountaineer to collect this promissory note, or any portion hereof. Covol waives
presentment,  demand,  notice,  protest  and all other  demands  and  notices in
connection with the delivery, acceptance, performance, default or enforcement of
this promissory note.

                  THIS NOTE SHALL BE GOVERNED BY, AND CONSTRUED AND  INTERPRETED
IN  ACCORDANCE  WITH,  THE  LAWS  OF NEW  YORK,  WITHOUT  GIVING  EFFECT  TO ANY
PROVISIONS  THEREOF  THAT PERMIT OR REQUIRE THE  APPLICATION  OF THE LAWS OF ANY
OTHER JURISDICTION.


                            COVOL TECHNOLOGIES, INC.


                                                     By:
                                                           Name:
                                                           Title: