Save Our Canyon: What is the Extent of Expansion of the Azusa Rock Quarry Plan?

Azusa Rock Quarry is located in the city of Azusa, California, near the border of the city of Duarte (see map below). Note: Images may take some time to load.

Vulcan Materials Company or its subsidiaries owns several parcels of land in Azusa. Three parcels make up the 190 acres allowed for mining under the current Conditional Use Permit (CUP). Vulcan wants to expand the mining operation by adding the west-most 80 acres to a new CUP.

However, Vulcan is marketing the proposal as a swap of acreage, saying that they will stop all mining on the east side of the quarry. The fallacy of this claim is that the best of this acreage has already been mined (even going beyond the eastern and western boundaries). The image below is a satellite photo of the Vulcan mine and the proposed expansion.

The image below shows the proposed Vulcan mining expansion as seen from Azusa (east of the mine).

The image below shows the proposed Vulcan mining expansion as seen from Duarte (west of the mine).

Vulcan Materials Company claims their new mining plan substitutes 80 acres on the west for 80 acres on the east. However, as seen below, at least 16 of those 80 acres on the east have already been mined:

¹

Vulcan lies

Vulcan goes so far as to claim that all 80 acres on the east are "yet to be mined," a boldfaced lie:

"The method by which the disturbance acreage will remain approximately equal is due to the permitted, but yet to be mined, 80 acre area on the east side being exchanged for 80 acres on the west side..."¹

However, at least 16 of those 80 acres have already been at least partially mined, as seen above. In fact, Vulcan themselves use the east side as an example picture of mined and un-mined areas.²

Aggregate mining increase

In addition, Vulcan claims that they gain no additional rock reserves from this plan:

"While the current application now seeks permissions to mine and reclaim the west 80-acre parcel, the applicant is not seeking enhanced reserves."³

However, the amount of aggregate available under the current mining plan continues to shrink over time.

Document	Aggregate
DEIR	121.5 MT
Appendix C.5.4	106.5 MT
Lilburn 4/22/10 memo1	81.7 MT2
1"Responses to Questions on Volumes" dated April 22, 2010. 2Table 3 lists the total amount of material at 108.9 MT, which at 25% overburden is 81.7 MT aggregate.

Lilburn's April 22 memo actually admits for the first time that the amounts of aggregate is greater under the revised mining plan compared to the current plan.⁴ However, Lilburn's April 22 adjustment still over-estimates the amount of aggregate available under the current plan. AGI Geotechnical produced computerized volumetrics measurements of aggregate amounts available under the current plan, using contour maps included in the environmental impact report (EIR). These measurements demonstrated that there were only 72 million tons of combined aggregate and overburden available under the current plan. At 25% overburden, this would amount to only 54 million tons of aggregate - less than half of what was claimed in the EIR and only two-thirds of Lilburn's April 22 estimate.

Vulcan and Lilburn contradict each other

Vulcan Materials and Lilburn Corporation have produced different values for the amount of material available from the 1988 mining plan. According to Vulcan Materials, 80% of the aggregate available under the current plan is on the east side and 20% is on the west side (Appendix C.5.4 Calculated Volumes Comparison 3.9.10, FEIR). However, Lilburn says that the amount of material on the east and west sides are nearly equal (27.5 vs. 25.0 mcy). AGI Geotechnical’s report shows that Vulcan has inflated the volume of material on the east side of the quarry by 50%, while Lilburn has inflated the volume of material on the west side of the quarry by 140%. Lilburn agrees that AGI is correct about the volume on the east side, while Vulcan agrees that AGI is correct about the volume on the west side.

Plan	VMC	Lilburn 4/22	Lilburn 5/6	AGI
Current
East	41.0 mcy1	27.5 mcy2	48.7 mcy7	24.2 mcy3
West	10.3 mcy4	25.0 mcy5	18.3 mcy7	10.4 mcy3
Total	51.3 mcy6	52.5 mcy6	67.0 mcy7	34.6 mcy3
Proposed	66.6 mcy6	60.9 mcy6	60.9 mcy6	61.0 mcy3
Difference	15.3 mcy	8.4 mcy	8.4 mcy	26.4 mcy
1Appendix C.5.4 Calculated Volumes Comparison 3.9.10 (http://www.ci.azusa.ca.us/DocumentView.aspx?DID=4385) FEIR states that 80% of the reserves available under the current mining plan are on the east side of the quarry. 80% of 51.3 mcy is 41.0 mcy. 2Calculated by subtracting the West volume (25.0 mcy) from the Total  volume (52.5 mcy). 3AGI Geotechnical report “Project No.20-3401-01” (http://www.saveourcanyon.org/3401-01.pdf). 4Appendix C.5.4 Calculated Volumes Comparison 3.9.10 FEIR states that 20% of the reserves available under the current mining plan are on the west side of the quarry. 20% of 51.3 mcy is 10.3 mcy. 5Responses to Questions on Volumes, dated April 22, 2010, “AGI Calculations”. 6Responses to Questions on Volumes, dated April 22, 2010, Table 4. 7Responses to Questions on Volumes5-6, dated May 6, 2010, Figure 3.

However, in their May 6 memo,9 Lilburn suddenly came up with another 14.5 mcy, resulting from a decrease of material from the west side (from 25 to 18 mcy) and an increase on the east side from 27 to 49 mcy. It isn’t clear to us how the amount on the east side could nearly double over the course of two weeks.

Conclusions

According to AGI Geotechnical produced volumetrics computations, the revised mining plan produces an additional 55 million tons of material compared with the current mining plan. At a mining rate of 5 million tons per year, the additional 55 million tons of material available under the revised plan extends mining activity at Fish Canyon from 14 years to 25 years–or from 2024 to 2035, just three years prior to the expiration of Vulcan’s conditional use permit. The city of Azusa doesn’t need an additional 11 years of blasting, silica dust, and negative environmental impacts.

References

1. V. Mining Operation Plan, page 61.
2. III. Location & Environmental Setting, photo 7, page 49.
3. I. Table of Contents & Exec. Summary, page 5.
4. "Responses to Questions on Volumes" dated April 22, 2010, Table 4.

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