Abstract: In China, many mental open-pit mines are facing the challenge of land acquisition under the strict control of mining land. The internal dump has many advantages including less land acquisition and short transportation distance, while in large metal open-pit mines with complex ore deposit conditions （particularly those that are steeply dipping or vertical with short strike lengths） existing internal dumping theories often cannot be directly or effectively applied. Taking the typical steeply dipping Shuguang Gold and Copper Open-pit Mine as an example, demonstrating the necessity of open-pit mine limit optimization under forest land constraints based on current geological grade models and economic parameters of limit optimization. Conducting a feasibility study on internal dumping and formulating a mining schedule for the Shuguang Gold-Copper Mine in response to the practical issues of insufficient capacity in the external dump, long hauling distance, and high operational costs. Under stringent external constraints （particularly forest land restrictions）, this study breaks away from the traditional internal dumping mode that relies on gently dipping mines. It proposes a new internal dumping approach for steeply dipping metal open-pit mines, characterized by “intensive mining in the initial area, coordinated zonal advancement, and separation of mining, stripping and dumping operations”. The application results show that the final pit of the Shuguang Gold-Copper Mine has formed three distinct pit bottoms. This unique pit geometry provides potential space for the construction of an internal dump. Constraints on forest land prevent the extraction of 18.28 million tons of hanging wall ore, thereby demonstrating the substantial impact of external restrictions on open-pit mining operations. The Shuguang Gold-Copper Mine primarily consists of two mines: Beishan and West Beishan. The Beishan Mine is located closer to the external dump and has a lower mining level. Prioritizing its excavation can create 3.79 million m³ of internal dumping space within the open-pit site, effectively alleviating the insufficient capacity of the external dump. Meanwhile, waste rock generated from the West Beishan Mine can be backfilled into the internal dump formed in the Beishan Mine, significantly reducing haulage distance. After implementing internal dumping, it is estimated that transportation costs can be reduced by approximately 70 million yuan, leading to a notable decrease in production costs. This paper can provide ideas and solutions for the limit optimization and internal dump design of metal open-pit mine under external constraints.