<span style="font-size: 11pt; font-family: "微软雅黑","sans-serif"; mso-ascii-font-family: Tahoma; mso-hansi-font-family: Tahoma; mso-bidi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">露天矿薄煤层开采工艺方法研究</span>