6. Authorized Dispositions. The limitations that subsections (a) and (b) [Maine cite subsections (1) and (2)] impose on the persons who may take free of a security interest apply of course only to unauthorized sales by the debtor. If the secured party authorized the sale in an express agreement or otherwise, the buyer takes free under Section 9-315(a) [Maine cite section 9- 1315, subsection (1)] without regard to the limitations of this section. (That section also states the right of a secured party to the proceeds of a sale, authorized or unauthorized.) Moreover, the buyer also takes free if the secured party waived or otherwise is precluded from asserting its security interest against the buyer. See Section 1-103.

7. Oil, Gas and Other Minerals. Under subsection (d) [Maine cite subsection (4)], a buyer in ordinary course of business of minerals at the wellhead or minehead or after extraction takes free of a security interest created by the seller. Specifically, it provides that qualified buyers take free not only of Article 9 [Maine cite Article 9-A] security interests but also of interests "arising out of an encumbrance." As defined in Section 9-102 [Maine cite section 9-1102], the term "encumbrance" means "a right, other than an ownership interest, in real property." Thus, to the extent that a mortgage encumbers minerals not only before but also after extraction, subsection (d) [Maine cite subsection (4)] enables a buyer in ordinary course of the minerals to take free of the mortgage. This subsection does not, however, enable these buyers to take free of interests arising out of ownership interests in the real property. This issue is significant only in a minority of states. Several of them have adopted special statutes and nonuniform amendments to Article 9 to provide special protections to mineral owners, whose interests often are highly fractionalized in the case of oil and gas. See Terry I. Cross, Oil and Gas Product Liens--Statutory Security Interests for Producers and Royalty Owners Under the Statutes of Kansas, New Mexico, Oklahoma, Texas and Wyoming, 50 Consumer Fin. L. Q. Rep. 418 (1996). Inasmuch as a complete resolution of the issue would require the addition of complex provisions to this Article, and there are good reasons to believe that a uniform solution would not be feasible, this Article leaves its resolution to other legislation.