James Sandle, federal prisoner # 66616-079, appeals the district court’s denial of his 18 U.S.C. § 3582(c)(2) motion for a reduction of his sentence under the recent *947 crack cocaine guidelines amendments. He argues that the district court abused its discretion in denying his § 3582(c)(2) motion; that the district court should have reduced his sentence based on the recent crack cocaine guidelines amendments; and that his statutory mandatory minimum sentence was improperly based on his pri- or conviction for simple possession.

A district court’s decision whether to reduce a sentence is reviewed for an abuse of discretion, and its interpretation of the Guidelines is reviewed de novo. United States v. Evans, 587 F.3d 667, 671-72 (5th Cir. 2009), cert. denied, — U.S. -, 130 S.Ct. 3462, 177 L.Ed.2d 1064 (2010). Because Sandle was subject to a statutory mandatory minimum sentence of 240 months of imprisonment under 21 U.S.C. § 841(b)(l)(A)(iii), the district court lacked authority to impose a sentence below the statutory minimum sentence. See United States v. Carter, 595 F.3d 575, 577, 579-81 (5th Cir. 2010); see also United States v. Robinson, 353 Fed.Appx. 941, 942 (5th Cir. 2009). Sandle’s reliance on Spears v. United States, - U.S. -, 129 S.Ct. 840, 172 L.Ed.2d 596 (2009), is misplaced as Spears did not involve a § 3582(c)(2) motion. See Spears, 129 S.Ct. at 841-45.

Sandle’s argument challenging his original sentencing may not be raised in a § 3582(c)(2) motion. A § 3582(c)(2) motion “is not a second opportunity to present mitigating factors to the sentencing judge, nor is it a challenge to the appropriateness of the original sentence.” United States v. Whitebird, 55 F.3d 1007, 1011 (5th Cir. 1995). Therefore, this argument is not cognizable in a § 3582(c)(2) motion. See Evans, 587 F.3d at 674.

AFFIRMED.