The Relationship Between Ore and Waste Rock

1. Relativity: The Dynamically Shifting Boundary

1.1 Technology-Driven Boundary Shifting

Throughout the evolution of the mining industry, technological advancements have acted like a magical key, continually pushing the boundaries between valuable ore and waste rock. Take iron ore extraction as an example: in the past, limited beneficiation techniques meant that ores with Fe content below 30% were typically dismissed as mere waste, deemed entirely unprofitable for mining. However, with the advent of high-pressure roller milling combined with dry magnetic separation technology, the landscape has been dramatically transformed. This cutting-edge approach now enables the efficient separation of iron-bearing minerals from low-grade iron ores, turning even waste rock containing 10–20% Fe into viable resources ready for recovery—and, quite literally, unlocking new value from what was once considered worthless.

Taking gold mines as another example, low-grade gold ore waste—once discarded due to technological limitations, despite containing gold levels between 0.3 and 1 g/t—has now been transformed into valuable resources thanks to the advent of heap leaching technology. This innovative method allows for the successful extraction of gold from previously overlooked, low-grade mine waste, turning what was once considered mere refuse into a lucrative asset. These compelling examples vividly demonstrate how advancements in technology play a decisive role in redefining the boundary between ore and waste—a boundary that is no longer fixed but continually reshaped by human ingenuity, much like an invisible hand rewriting the map of mineral resource utilization.

1.2 The Impact of Economy and Policy

Economic factors and policy guidance act like two powerful conducting rods, profoundly influencing the boundary between ore and waste rock. When ore prices continue to rise, economic incentives prompt mining companies to revisit low-grade ores that were previously shelved due to high costs. Take iron ore as an example: during periods of favorable market conditions, even ores with an Fe content as low as 25% become economically viable to extract—thanks to price support—thus naturally being classified as mineable resources.

On the policy front, the country's macroeconomic policies have played a positive and guiding role in transforming ore and waste rock. In 2021, the National Development and Reform Commission, along with nine other ministries, jointly issued the "Guiding Opinions on the Comprehensive Utilization of Bulk Solid Waste during the 14th Five-Year Plan," which clearly outlined the direction for the resourceful use of waste rock. Driven by these policies, many mining enterprises have actively launched projects such as producing sand and gravel from waste rock, effectively converting large volumes of waste rock into essential construction materials like sand and aggregate. This not only addresses the longstanding challenge of waste rock disposal but also generates significant economic benefits. As a result of this policy-driven approach to waste rock utilization, the line between waste rock and ore is becoming increasingly blurred, paving the way for sustainable development in the mining industry.

2 Symbiosis: The Inevitable Connection of the Mining Process

2.1 Spatial Symbiosis: Co-occurrence of Ore Bodies and Host Rocks

Deep underground, the ore body is like a treasure wrapped snugly in its surrounding "cradle" of country rock. When we carry out mining operations—whether it’s excavating tunnels during underground mining or stripping away surface overburden in open-pit mining—it’s inevitable that we’ll come into contact with this surrounding rock. In fact, both underground and open-pit mining generate significant amounts of waste rock, which essentially consists of the country rock surrounding the ore body—as well as any gangue minerals mixed within the ore itself.

In underground mining, extensive tunneling is required to create accessways leading to the ore body—tunnels that eventually become waste rock as they pass through the surrounding rock. Similarly, in open-pit mining, the overlying thick layer of waste rock must first be removed to expose the ore body beneath. Spatially, the ore body and its surrounding rock are intimately connected, and this symbiotic relationship is an unavoidable objective reality throughout the mining process.

2.2 The "Quality-Mass" Relationship in Mining

During the mining process, there exists a subtle "quality-mass" relationship between ore and waste rock. When we extract ore from the mineral deposit, it often ends up mixed with some waste rock—much like inadvertently stirring a few impurities into a delicious bowl of soup. This inclusion of waste rock not only lowers the grade of the extracted ore, compromising its quality, but also increases the difficulty and cost of subsequent beneficiation processes.

This phenomenon of waste rock mixing can also lead to the loss of some ore. During the mining process, for various reasons, certain ores that could have been mined and utilized end up being discarded along with the waste rock, resulting in a wastage of valuable resources. Consequently, there is a close quantitative relationship among the waste rock inclusion rate, ore loss rate, and dilution rate. Therefore, reducing the waste rock inclusion rate while improving ore recovery and quality has become a key performance indicator for optimizing mining processes—and it remains a critical issue that mining companies must prioritize and address throughout their production operations.

3 The Boundary Between Law and Economics: Balancing Compliance and Efficiency

3.1 Legal Definition: Taking the Crime of Illegal Mining as an Example

Within the framework of the law, accurately distinguishing between ore and waste rock is crucial—it not only affects the legality of mining activities but also determines the scope of legal liability. Take the crime of illegal mining as an example: in judicial practice, whether the materials involved are classified as ore or waste rock often becomes the key factor in determining the nature of the case.

The 2023 illegal mining case involving Xu Moumou is a typical example. Xu Moumou utilized granite offcuts left behind at the site of a former quarry, crushing and processing them into aggregate for sale. These granite offcuts were waste materials resulting from artificial mining activities—far from naturally occurring mineral resources. After reviewing the case, the court ruled that Xu Moumou’s actions did not constitute the crime of illegal mining, as the stone materials used for crushing were not natural mineral resources and thus failed to meet the statutory criteria for criminal liability under this offense. Moreover, Xu’s activity of extracting these mining byproducts was not classified as "mining" itself. Additionally, there remains no clear legal provision mandating the need for an extraction permit when exploiting such mining waste. However, if the extracted material happens to meet industrial-grade mineral standards—and if extraction occurs without the requisite mining license—it would likely be deemed illegal mining under the law. This case clearly underscores that, legally speaking, distinguishing between ore and waste rock requires strict criteria and thorough, rule-based assessment.

3.2 Economic Trade-offs: Extraction Costs vs. Value

From an economic perspective, ore mining is a carefully balanced trade-off between cost and value. In this process, the cost of waste-rock management is a critical factor that cannot be overlooked. To properly handle the massive amounts of waste rock generated during mining, mining companies must invest significant funds in constructing waste-rock yards, purchasing transportation equipment, and more. Such expenditures directly drive up the overall cost of ore extraction.

If excessive waste rock is mixed in, it can lead to a sharp increase in mineral processing costs. This is because the beneficiation process requires significant amounts of energy, chemicals, and equipment to separate the valuable minerals from the waste rock. As the proportion of waste rock rises, the workload for mineral processing grows accordingly, driving costs dramatically higher. Moreover, if the ore grade is too low, even if extraction and beneficiation are successfully carried out, the eventual profits may fail to cover the expenses—making the operation entirely unprofitable. Therefore, when deciding whether to mine a particular ore deposit, mining companies must carefully weigh the balance between waste-rock disposal costs and the intrinsic value of the ore itself. Only when the ore’s value is sufficiently high—enough to offset both the extraction and processing expenses while still generating a healthy profit—does the project become economically viable. Otherwise, even if the ore meets industry standards, its development might be put on hold. This economic feasibility analysis acts like a precise measuring tool, delicately defining the boundary between valuable ore and unwanted waste rock—and ultimately guiding mining companies toward well-informed, rational decisions.

3 Core Quantitative Calculations for Ore and Waste Rock

3.1 Calculation of Quantitative Indicators: Quantification Based on Mining Scale

3.1.1 Waste Rock Contamination Rate (Y): A Measure of the Degree of Waste Rock Mixing

In mining operations, the waste rock inclusion rate is a critical metric used to accurately assess the extent to which waste rock has mixed with the mined ore. The calculation formula is Y = Qy/Qc × 100%, where Qy represents the amount of waste rock mixed into the extracted ore (in tons), and Qc denotes the total volume of ore extracted (in tons).

Take a certain iron ore mine as an example: During one mining operation, a total of 1,000 tons of ore was extracted. After careful inspection and statistical analysis, it was found that 200 tons of waste rock had inadvertently mixed in. Using the formula for calculating the waste-rock inclusion rate, we can determine that the inclusion rate Y for this particular extraction was 200 ÷ 1,000 × 100% = 20%. This figure clearly indicates that 20% of the ore extracted during this operation consisted of waste rock.

The rate of waste rock contamination has a direct and significant impact on subsequent mineral processing operations. The inclusion of large amounts of waste rock will undoubtedly place a substantial additional burden on the beneficiation plant, requiring more time, energy, and resources to effectively separate the valuable minerals from the unwanted waste. This not only leads to a sharp increase in beneficiation costs but may also compromise both the efficiency of the process and the quality of the final product. Therefore, strictly controlling the waste rock contamination rate during mining is one of the key steps in enhancing mining profitability and maximizing resource utilization. Mining companies typically implement a range of advanced mining technologies and management strategies—such as optimizing mining processes and strengthening on-site supervision—to minimize waste rock contamination as much as possible, ensuring that mining operations remain efficient and cost-effective.

3.1.2 Ore Loss Rate (S) and Recovery Rate (Hk): Assessing Resource Utilization Efficiency

The ore loss rate (S) and recovery rate (Hk) are core indicators for measuring the efficiency of mineral resource utilization, reflecting from different perspectives how effectively ore resources are being exploited during the mining process. The formula for calculating the ore loss rate S is S = Qs/Q × 100%, where Qs represents the amount of lost ore, and Q denotes the industrial ore reserves. Meanwhile, the formula for the ore recovery rate Hk is Hk = (Q - Qs)/Q × 100%. These two metrics maintain a close complementary relationship, expressed as Hk = 100% - S.

Taking a certain copper mine as an example, the mine has industrial reserves of 5,000 tons. During the mining process, due to various factors—such as limitations in extraction technology and complex geological conditions—1,000 tons of ore were lost. Using the formula for calculating ore loss rate, we find that the mine’s ore loss rate S is calculated as follows: S = 1,000 ÷ 5,000 × 100% = 20%. Furthermore, based on the relationship between ore recovery rate and loss rate, the ore recovery rate Hk can be determined as: Hk = 100% - 20% = 80%.

This set of data clearly shows that during the mining process at this copper mine, 20% of the ore resources were lost, while only 80% of the ore was successfully extracted. The ore recovery rate directly reflects the mine's efficiency in utilizing its resources—higher recovery rates indicate more comprehensive resource utilization, which in turn strengthens the mine's economic benefits and its capacity for sustainable development. Therefore, improving the ore recovery rate is one of the key objectives that mining enterprises strive to achieve. To reach this goal, mining companies are continuously increasing their investments in research and development, introducing cutting-edge mining technologies and equipment, optimizing mining processes, and enhancing production management—all aimed at minimizing ore losses, boosting resource recovery, and ultimately ensuring the long-term sustainability of the mine.

3.2 Calculation of Qualitative Indicators: Quantification Based on Grade

3.2.1 Ore Dilution Rate (P): The extent to which ore quality has decreased

The ore dilution rate (P) is a key indicator that measures the extent to which ore quality declines due to the mixing of waste rock, and it plays a crucial role in assessing the impact of mining operations on ore quality. The basic calculation formula is P = (C - Cc)/C × 100%, where C represents the grade of industrially recoverable ore reserves, and Cc denotes the grade of ore actually extracted.

In real-world mining scenarios, the situation is often more complex. When waste rock contains small amounts of valuable components, the formula needs to be adjusted to more accurately calculate the ore dilution rate. The revised formula is: P = [(C - Qc × Cc / (Q - Qs) - Cy × Qy / (Q - Qs)) / C] × 100%, where Cy represents the grade of the waste rock.

Taking a certain lead-zinc mine as an example, the mine’s industrial-grade content C is 15%. After mining, the grade of the extracted ore, Cc, drops to 12%. Using the basic formula, we can calculate the ore dilution rate P as follows: P = (15% - 12%) ÷ 15% × 100% = 20%. This indicates that due to the mixing of waste rock, the grade of the extracted ore has decreased by 20% compared to the original industrial-grade ore, resulting in a noticeable decline in ore quality.

The ore dilution rate直观 reflects the extent to which ore quality declines due to the mixing of waste rock. Ore dilution not only affects the difficulty and cost of subsequent beneficiation processes but can also lead to a deterioration in concentrate quality, ultimately impacting the market competitiveness of the final product. Therefore, effectively controlling the ore dilution rate during mining operations is a critical measure for ensuring ore quality and enhancing the economic efficiency of mining activities. Mining companies typically employ strategies such as optimizing mining methods, intensifying geological exploration, and upgrading mining technology to minimize the amount of waste rock mixed in, thereby keeping ore dilution under control and maintaining—and even improving—consistency in ore quality.

3.3 Third-level reserve calculation: Quantifying the link to mining planning

3.3.1 Prospective Reserves (Qk): The Resource Base for Long-Term Extraction

Exploitable reserves (Qk) are a critical resource foundation for the long-term operation of a mine, playing a key guiding role in planning the mine's long-term development projects. The calculation formula is Qk = A × tk × (1 - r) / K, where A represents the annual mine production rate (units: t/y), tk denotes the duration of exploitable reserve availability (units: y, typically ranging from 5 to 10 years), r is the waste rock inclusion rate (units: %), and K stands for the ore recovery rate (%).

Suppose a mine has an annual production capacity of A = 100,000 tons/year, with a planned service life for its development reserves set at tk = 8 years. The dilution rate, r, is 20%, and the ore recovery rate, K, is 80%. By plugging these figures into the formula, we can calculate the mine’s development reserves as follows: Qk = 10 × 8 × (1 - 0.2) ÷ 0.8 = 800,000 tons. These 800,000 tons of development reserves provide a solid resource guarantee for the mine’s long-term operations over the next eight years. Based on this data, the mine can now strategically plan its development projects—such as designing the layout of underground roadways and constructing efficient transportation systems—to ensure that mining operations remain sustainable and stable well into the future.

3.3.2 Mining Reserve (Qc) and Preparatory Reserve (QB): Ensuring Short-Term Production

Mining prepared reserves (Qc) and backup reserves (QB) are critical indicators that ensure the continuous operation of a mine's short-term production, providing robust support for the mine's daily operations. The formula for calculating mining prepared reserves Qc is Qc = A × tc × (1 - r) / K, where tc represents the holding period of the prepared reserves (in years, typically around 1 year). The formula for calculating backup reserves QB is QB = A × tB × (1 - r) / (K × 12), where tB denotes the holding period of the backup reserves (in months, usually 6 months).

Taking the aforementioned mine as an example, we know that A = 100,000 tons/year, tc = 1 year, r = 20%, and K = 80%. Substituting these values into the preparatory reserve formula, we can calculate Qc as follows: Qc = 10 × 1 × 0.8 ÷ 0.8 = 100,000 tons. This preparatory reserve of 100,000 tons provides a clear target and resource basis for the mine's preparatory work over the next year. Based on this data, the mine can effectively plan activities such as driving preparatory roadways and arranging mining areas, ensuring that preparatory operations meet production requirements.

Re-calculating the reserve for preparatory mining, given that tB = 6 months and all other data remain unchanged, substituting into the reserve formula yields QB = 10 × 6 × 0.8 ÷ (0.8 × 12) = 50,000 tons. This reserve of 50,000 tons provides crucial guidance for the mine’s preparatory work over the next six months, enabling the mine to efficiently organize production, secure adequate mining equipment, personnel, and materials, and ensure that mining operations proceed smoothly—thereby maintaining the continuity and stability of mine production.

4 Calculation Example: Application Based on Actual Mineral Types

4.1 Example of Metal Ore: Quantitative Calculation of Iron Mining

4.1.1 Known Conditions

A certain iron ore deposit has an industrial reserve of Q = 20,000 tons with a grade of C = 35%. During mining, the amount of ore extracted was Qc = 16,000 tons, of which 3,200 tons were waste rock containing impurities at a grade of Cy = 5%. Meanwhile, ore losses amounted to Qs = 4,000 tons. In the actual mining process, these data were obtained through a combination of geological exploration, detailed operational records, and rigorous testing and analysis of both ore and waste materials. Geological explorers employed advanced techniques such as drilling and geophysical surveys to accurately determine the deposit's industrial reserves and mineral grade. Throughout the extraction phase, precise measurement tools and meticulous site management ensured reliable recording of key metrics, including the quantity of ore extracted, the volume of waste rock mixed in, and the extent of ore loss. These meticulously collected data serve as the foundation for subsequent calculations and analyses, providing critical insights that are essential for evaluating the economic viability of the iron ore operation and optimizing resource utilization efficiency.

4.1.2 Calculation Process and Results

Waste rock inclusion rate Y = (3200 / 16000) × 100% = 20%; ore loss rate S = (4000 / 20000) × 100% = 20%; recovery rate Hk = 80%. The grade of mined ore Cc is calculated as follows: Cc = [(20000 - 4000) × 35% - 3200 × 5%] / 16000 = 27%. Meanwhile, the dilution rate P is determined by: P = (35% - 27%) / 35% × 100% ≈ 22.86%. The development reserve Qk is computed using the formula: Qk = 16000 × 5 × (1 - 20%) / 80% = 80,000 tons. Here, we assume A = 16,000 tons/year and tk = 5 years. In the calculation process, each step strictly follows the formulas previously outlined. For the waste rock inclusion rate, we directly divide the amount of waste rock mixed in by the total mined ore volume and multiply by 100% to obtain the proportion of waste rock. Similarly, the ore loss rate and recovery rate are calculated based on their respective formulas, derived from the relationship between ore losses and industrial reserves. The grade of mined ore is determined by carefully considering factors such as the grade of ore in industrial reserves, the amount of lost ore, and the grade of waste rock—resulting in a complex yet precise computation. The dilution rate, meanwhile, is calculated by comparing the difference between the grade of mined ore and the grade of industrial reserves, expressed as a percentage of the latter. Finally, the development reserve is determined by integrating multiple parameters, including the mine’s annual production rate, the duration for which the reserve is expected to last, the waste rock inclusion rate, and the ore recovery rate—all combined through a well-defined formula. Each step in this calculation is executed with meticulous attention to detail, ensuring the accuracy and reliability of the results, thereby providing robust support for subsequent analysis and decision-making processes.

4.1.3 Results Analysis

The waste rock inclusion rate of 20% at this mine falls within a reasonable range, but the dilution rate—approximately 23%—is slightly higher than desired, indicating a need to optimize the mining process (e.g., by enhancing the removal of gangue). Meanwhile, the recovery rate of 80% meets the basic requirements for iron ore extraction, and the proven reserves can support five years of production. However, continuous geological exploration and resource assessment are essential to ensure ongoing replenishment of these reserves. From the results, the waste rock inclusion rate remains within an acceptable range, suggesting that control over waste rock contamination during mining operations has largely achieved the intended level. Nevertheless, the slightly elevated dilution rate may stem from insufficient removal of gangue during the recovery process or potential shortcomings in the current mining techniques. To address this, it is crucial to further refine the mining procedures and strengthen efforts to eliminate gangue entirely, thereby reducing the dilution rate and improving ore quality. The 80% recovery rate aligns with the fundamental standards for iron ore extraction, highlighting that the mine has made notable progress in maximizing resource utilization. Additionally, the proven reserves can sustain production for five years, providing a solid foundation for stable operations. Yet, to ensure the long-term sustainability of the mine, ongoing geological exploration remains vital—enabling the discovery of new resources that can supplement existing reserves and guarantee the mine’s ability to operate efficiently and reliably over the coming decades. By thoroughly analyzing these findings, we can develop targeted recommendations and strategies for the mine’s future production and management, ultimately fostering efficient, sustainable growth while maintaining operational excellence.

4.2 Example of Non-Metallic Minerals: Calculation of Waste Rock from Limestone Mines Used for Cement

4.2.1 Known Conditions

The industrial reserves of calcareous raw materials from a certain cement mine amount to Q = 15,000 tons, with a required CaO content of at least 45% (as per industry standards). The amount of ore extracted is Qc = 12,000 tons, of which 2,400 tons are waste rock (with CaO content of 40% and MgO content of 4%, meeting the criteria for identifying cement-related waste rock). Meanwhile, ore losses total Qs = 3,000 tons. In the mining of calcareous raw materials used in cement production, these known parameters were also obtained through meticulous geological exploration and rigorous monitoring throughout the extraction process. Geological surveys precisely determined the industrial reserves and established the relevant industry standards, while the extraction process involved accurate recording of the quantities of ore mined, waste rock mixed in, and ore lost. Additionally, the composition of the waste rock was analyzed to verify whether its CaO and MgO levels met the criteria for classification as cement-related waste material. These data are critical for assessing the mining conditions of calcareous raw materials intended for cement production and for guiding subsequent production applications. They form the foundation for ensuring both the quality of cement manufacturing and the efficient, sustainable utilization of mineral resources.

4.2.2 Calculation Process and Results

The waste rock inclusion rate Y is calculated as 2400/12000 × 100% = 20%; the ore loss rate S is 3000/15000 × 100% = 20%. The grade of CaO in the extracted ore, Cc, is determined by the formula: Cc = [(15000 - 3000) × 48% - 2400 × 40%] / 12000 = 44% (assuming the original ore contained 48% CaO). Since Cc is below the required 45%, it’s necessary to adjust the raw material mix—perhaps by blending in higher-CaO ores. The waste rock utilization rate is approximately 44.4%, calculated as 2400 / (2400 + 3000) × 100% ≈ 44.4% (following the logic outlined in the "Method for Calculating Waste Rock Utilization Rate in Iron Ore"). In these calculations, both the waste rock inclusion rate and ore loss rate are computed similarly to those used in metal ore examples—both rely on straightforward mathematical formulas. However, the calculation of the CaO grade in the extracted ore involves a more complex process, taking into account factors such as the original ore’s CaO content, the amount of ore lost during extraction, and the CaO content of the waste rock. Given that the CaO grade in the extracted ore falls short of the industry’s minimum requirements, it’s essential to fine-tune the raw material mix to ensure the quality standards needed for cement production. Meanwhile, the waste rock utilization rate is derived based on the ratio of waste rock volume to the total volume of both waste and lost ore, aligning with the principles outlined in the "Method for Calculating Waste Rock Utilization Rate in Iron Ore." These calculations provide a comprehensive overview of the mining and utilization processes for lime-bearing minerals intended for cement production, offering crucial insights that inform critical decisions in subsequent production planning.

4.2.3 Results Analysis

The mixing of waste rock into the mined ore has resulted in the extracted ore failing to meet cement raw material standards, necessitating an optimization of the waste-rock separation process during mining. Currently, the utilization rate of waste rock stands at around 44%, but this can be further enhanced by crushing and processing the waste rock for use as a cement additive or roadbase material, thereby elevating the overall level of resource recovery. Analysis of the results reveals that the presence of waste rock has prevented the extracted ore from meeting the required standards for cement production, significantly impacting the quality of the final cement product. Consequently, optimizing the waste-rock separation process in mining operations has become urgently needed. By refining the existing process and boosting its efficiency, we can minimize waste-rock contamination, ultimately improving the quality of the extracted ore and ensuring it meets the stringent demands of cement manufacturing. Although the current waste-rock utilization rate of approximately 44% already represents a meaningful level of recovery, there remains considerable room for improvement. Further processing of the waste rock—such as crushing and reusing it as a cement ingredient or roadbase material—can fully realize its potential as a valuable resource, enhancing resource efficiency while reducing environmental impact. Based on this analysis, clear directions for improving both the extraction of limestone resources for cement production and the effective utilization of waste rock have been identified. These insights not only pave the way for more efficient resource management but also support the long-term goal of sustainable development.

5 Application Extension: Computational Integration for the Resource Utilization of Waste Rock

5.1 Calculation of Waste Rock Utilization Rate: Taking Iron Ore as an Example

In the process of iron ore mining, the generation of waste rock is unavoidable. However, with the deepening of the concept of comprehensive resource utilization and advancements in technology, more and more waste rock is being recycled and reused. As a result, the utilization rate of waste rock has become a key indicator for measuring the level of comprehensive resource management in mines.

The formula for calculating the utilization rate of waste rock is: Iron ore waste rock utilization rate = (Amount of waste rock utilized / Total amount of waste rock generated) × 100%. This formula clearly illustrates the extent to which waste rock resources are being recycled and reused during the mining and processing of iron ore.

Take a large iron ore mine as an example: during one year of mining operations, the mine generated a total of 5,000 tons of waste rock. To achieve efficient resource utilization, the mine has actively explored ways to recycle and repurpose this waste rock. Specifically, 3,000 tons of waste rock have been used for underground backfilling, effectively supporting mined-out areas and preventing geological hazards such as surface subsidence. Meanwhile, 1,000 tons of waste rock have been processed into sand and gravel, yielding high-quality aggregates that are now widely used in the construction industry.

According to the calculation formula for waste rock utilization rate, the iron ore's waste rock utilization rate is calculated as follows: (3000 + 1000) / 5000 × 100% = 80%. This figure demonstrates that the iron ore mine has achieved significant success in the resourceful utilization of waste rock, with the majority of waste materials being effectively put to good use.

The waste rock utilization rate of this iron ore mine meets the "full-scale utilization" requirement outlined in the "Method for Calculating Waste Rock Utilization Rate in Iron Ore Mines" (GB/T 44028-2024). The introduction of this standard provides a unified framework and methodology for calculating waste rock utilization rates, effectively promoting the standardization and regularization of waste rock utilization in the iron ore industry. In practical applications, mining enterprises should strictly adhere to the standard's requirements, accurately calculate their waste rock utilization rates, and, in alignment with comprehensive resource utilization policies, continuously refine waste rock management strategies. This will not only enhance resource efficiency but also pave the way for sustainable development of mining operations.

5.2 Economic and Environmental Benefit Assessment: Case Study on Waste Rock Backfilling

In mining operations, waste rock backfilling is a common and effective method for the resourceful utilization of waste rock. Not only does it address the challenge of waste rock disposal, but it also delivers significant economic and environmental benefits.

From an economic perspective, waste rock backfilling can significantly reduce costs. Take a certain mine as an example: Previously, this mine had been purchasing aggregates externally for underground filling, at a unit price of 200 yuan per ton. However, with the widespread adoption of waste rock backfilling technology, the mine now utilizes the waste rock generated during its own mining operations for filling purposes. As a result, the cost of waste rock backfilling has dropped to just 80 yuan per ton. Assuming the mine’s annual filling requirement is 1,000 tons, the cost savings achieved through waste rock backfilling would amount to (200 - 80) × 1,000 = 120,000 yuan—equivalent to 120,000 yuan, or 120,000 RMB—per year. This substantial cost reduction not only enhances the mine’s overall economic efficiency but also strengthens its competitiveness in the market.

From an environmental perspective, waste rock backfilling reduces the surface accumulation of waste rock, thereby minimizing environmental issues such as dust emissions. According to the geothermal coal-saving and emission-reduction calculation logic outlined in Appendix F, after implementing waste rock backfilling to decrease surface stockpiling, annual dust emissions are reduced by approximately 5 tons. If left unchecked, this dust could severely pollute the surrounding air quality, posing significant health risks to local residents. By utilizing waste rock for backfilling, not only is atmospheric pollution from dust significantly curbed, but the risk of geological hazards like landslides and debris flows—potentially triggered by waste rock stockpiles—is also mitigated, ultimately safeguarding the delicate ecological balance of the surrounding area.