The essential elements of estoppel must be pleaded and proved. The burden of proving all the essential elements of estoppel is upon the party asserting it. First National Bank of Fleming v. Petzolt, 10 Cir., 262 F.2d 540, 545; Panhandle Pipe Supply Co. v. S.W. Pressey Son, 125 Colo. 355, 243 P.2d 756; Susman v. Exchange Nat. Bank of Colorado Springs, 117 Colo. 12, 183 P.2d 571. Estoppel was not pleaded as a defense but it was brought into the trial without objection and generally the case was tried and decided upon that issue.
Stevens at no time had a valid title, nor could he under the circumstances of this case convey a valid title. See Panhandle Pipe Supply Co. v. S. W. Pressey Son, 125 Colo. 355, 243 P.2d 756; 46 Am. Jur., Sales, Sec. 458, p. 620. Nor does any principle of estoppel apply under the circumstances of this case.
Thus, plaintiffs could not, by merely filing a self-created, self-described "land patent" that says, in effect, "we own the described property because we say we do," acquire or otherwise transfer those mineral interests, or any other interests in the property legally owned by others, to themselves. See Panhandle Pipe Supply Co. v. S.W. Pressey Son, 125 Colo. 355, 362, 243 P.2d 756, 760 (1952) (parties possessing no rights in real property interests are without power or authority to alter the ownership of those interests; "[o]ne without title to property can convey no title"); GMAC Mortgage Corp. v. PWI Group, 155 P.3d 556, 558 (Colo.App. 2006) (only the owner of an interest in real property "can encumber or convey the same"). Consequently, the trial court properly dismissed for failure to state a claim plaintiffs' complaint seeking entitlement to additional royalty payments on oil and gas production from defendant's wells based on plaintiffs' "Declaration of Land Patent."
Jury instructions should be couched in language clearly understandable, rather than in unusual terms leading to guesswork and speculation on the part of the jurors. Panhandle Pipe Supply Co. v. Pressey Son, 125 Colo. 355, 243 P.2d 756 (1952). We hold that the term "superseded" is one which is understandable to jurors, and therefore, we do not perceive error in its use.