During that inspection, the entire country is traversed at intervals depending on the quality of the vegetation. Comparisons were made with the descriptions of the Floristic Community Types and maps in Appendix 1 of Gibson et al 2004. A flora and vegetation study was completed and showed 33 species of the original Banksia Woodland species.
Species List - Native Taxa
A total of 6 wetlands were nominated on DOW mapping with two resource enhancement wetlands and four drainage and drainage lines across rangeland. The two resource enhancement wetlands are well vegetated and are excluded from the proposed excavation. To the west is Banksia Woodland which is included in the Gnangara – Moore River State Forest.
10m 2 Plot 5
Species List – Exotic Taxa
The sample plots were placed at the visual average vegetation, based on the best and worst criteria and therefore reflect the average vegetation condition for the site in terms of species richness and plant density. Pinaster Pines are also present in western springs, but are easily treated if they grow. No weed species were recorded in the eastern spring, but grasslands and associated exotic plants occur in the eastern spring.
Plant Density
No ecologically significant or endangered weed species were recorded for the western resource, although Ursinia anthemoides and Gladiolus sp were recorded. Both are widespread throughout Banksia Woodlands and coastal areas in the southwest and have become naturalized.
Vegetation Structure
Vegetation Condition
No comparable plant observed Caladenia huegelii T E No orchid plants or leaves observed Chamelaucium sp Gingin T E Distinctive. Diuris micrantha T V No orchid plants or leaves observed Diuris purdiei T E No orchid plants or leaves observed Eleocharis keigheri T V No orchid plants or leaves observed Eucalyptus leprophlioia T E No comparable eucalyptus observed Eucalyptus x balanties T E No comparable eucalyptus observed. Unlikely Thelymitra dedmaniarum T E No orchid plants or leaves of this type have been observed. Theymitra stellata T E No orchid plants or leaves of this type have been observed.
Vegetation Representation
The greatest potential impact on Banksia Woodland is in the adjacent State Forest to the west. Buffers and revegetation of the batter slopes to local native vegetation will be used to provide a long-term vegetated buffer of 50 meters to the State Forest and Banksia Woodland which will help protect this vegetation.
Fauna
Degraded pines on site may form irregular foraging habitat for black cockatoos, but they will be replaced by pit bottom pastures and banksia forest on test slopes, so over time there will be minimal or no impact on black cockatoos. During this process, the potential presence of significant fauna will be assessed in accordance with clearing principles. The clearing will be gradual, from the cleared land to the west and south towards the adjacent indigenous vegetation.
Wetlands and Riparian Communities
The vegetation of the wetland is located within the perimeter of Kunzea glabrescens, so that in effect a buffer of at least 50 meters will be maintained for the vegetation of the wetland. Where necessary to achieve a minimum of 50 metres, the excavation footprint will be reduced accordingly by a minor change as shown on Figure 1 in the main report. Groundwater flow is west to east below the proposed floor in the excavations and that flow will be maintained.
Clearing
1g Land Degradation • The excavation will be managed in a manner that does not lead to degradation of the soil and the integrity of the land, beyond normal development concerns. 1j Increase in flooding • The sand ridge lies above the low-lying soils that do not change. 1 Planning Matters • The identification, protection and use of sand resources is recognized in all government policies.
Dieback Management
When removing topsoil and clearing, vehicles will drive around the perimeter and then push inwards where possible. It is proposed that the remaining vegetation prior to the stage to be excavated be quarantined where possible to reduce vehicle entry. No soil or vegetation is brought to the site except that used in remediation and that which does not die.
Plants used in rehabilitation must be certified as being from die-back-free sources. When clearing land or fire lanes, vehicles must work from disturbed areas to the well;. Excavation will take place below ground level on the west side, and to the south towards the better vegetation and adjacent native vegetation, which will enable excavation to take place without affecting or contacting the native vegetation.
A shared operation will be operated where practicable, where the road transport vehicles only have access to one side of the stock pile or processing area and excavation vehicles work on the other side of the stock piles and processing, reducing the risk of contamination from road transport. DPAW has determined that material such as sand, taken from deeper in the regolith profile where there is no organic and other plant material, has a low risk of spreading degradation.
Weed Management Plan
This often refers to trucks that were carrying something else, such as grain, or earthmoving vehicles. Inspections to monitor the presence and introduction of environmental and declared weeds should be carried out annually or more frequently. Large weeds such as castor oil plant have not been observed, but if present, they should be periodically grubbed or spot sprayed with herbicide.
Grass surfaces can be sprayed with Fusilade or similar selective grass herbicides if required. All vehicles and equipment to be used during land clearing or land restoration must be clean and free of soil or plant material when they arrive on site. No soil or vegetation will be brought to the site, except for what will be used for rehabilitation.
Unwanted access to vegetated areas should be discouraged by means of signage, marking, lack of tracks, fencing and/or external fencing. Weed-infested topsoils may need to be moved to another location, used in weed-infested areas, buried with 500mm of soil/topsoil or moved to another location. No weed-contaminated or suspect soil or plant material may be brought onto the site.
Weeds should be sprayed with broad-spectrum sprays before planting or planting in weed-affected lands as needed.
CLOSURE OBLIGATIONS AND COMMITMENTS
Geotechnical
Closure Inventory
Any soil or other materials with drips and spills will be removed off-site to an approved waste site or location. Any waste will be collected and removed immediately from the site to an approved recycling or waste disposal area.
Post Mining Landuse
The bottom of the pit will be lowered to 0.5 to 1.0 meters above the highest known water table to allow better summer soil moisture and better grass growth for continued agricultural production. This is in line with the Guideline Winningsindustrie Regio Zuidwest, which is more applicable because the end use will be agricultural activities and pasture. The more leached sand is removed from the sand ridges, making the restored soils better able to retain moisture and phosphorus.
By lowering the pasture area, capillary action will take place and the pasture will be able to gain soil moisture in the summer. Measurements of the water table will be completed using the on-site water wells and piezometers installed in the floor during excavation. The final ground surface will be in accordance with the safety considerations of the Mine Safety and Inspection Act 1995 and the requirements and guidelines of the Department of Mines and Petroleum; for example Guidelines on Safety Boundary Walls around Abandoned Open Pits 1991.
The floor will be flat with a slight slope of 1 : 5 to 1 : 10 vertical to horizontal to enable a productive use of the agricultural land. The floor of the pit will be lowered to 0.5 to 1.0 meters above the highest water table in accordance with the Department of Water South West Region Guidance for Extractive Industries. Water table measurements will be completed using field water monitoring holes and additional piezometers installed in the floor during excavation, comparisons with measurements collected in September 2016 and geomorphology.
The final land surface will correspond to those nominated wetlands which will not be affected but will end up expanding.
Revegetation Considerations and Closure Objectives
Completion Criteria
Closure Implementation
- Closure of any ground under Rehabilitation
- Land Clearing Tree Removal and plant removal
- Land Restoration
- Revegetation Vegetation Establishment
The floor of the pit will be internally drained to a basal sump in later stages of excavation. The ground surface will be shaped to the requirements of the Mines Safety and Inspection Act 1994 and Regulations 1995 as a final land surface. Any vegetation fragments will either be spread on top of the topsoil or spread with the topsoil.
The soil surface will be evenly distributed in the rehabilitated areas in the summer or early autumn before the winter rains. Any weeds likely to significantly affect rehabilitation will be sprayed with Roundup or similar herbicide or removed, depending on the species involved. The species to be used for the 25 meter wide vegetation buffer to the west will be fast growing native native species as listed below.
The species will be selected on the advice of a consultant or the Ministry of Agriculture and Food. Management of wind erosion potential will be aided by the spread of shrubs and vegetation across topsoil on slopes and reconstructed soils where local native vegetation will be established. Revegetation will be monitored for 3 years after the closure of each part of the pit or until completion criteria are met.
During the late summer, an evaluation of the success of the rehabilitation will be made to determine the rehabilitation requirements for the following winter.
RESOURCE ENHANCEMENT
ADDITIONAL SURFACE AND GROUNDWATER DATA Winter groundwater elevation, based on Perth groundwater data and modified from field observations in late winter 2016. Property boundary Property boundary A - B BEFORE EXCAVATION and SHOWING EXPOSURE PROPOSED - EXCAVATION AND GROUND SURFACE EXCAVATION. The height of the floor will be determined with a piezometer during excavation at 0.5 - 1.0 m above the highest winter water level.
59 Elevation is determined with a piezometer during excavation at 0.5 - 1.0 m above the highest winter water level CONCEPT FINAL CONTOUR PLAN Figure 1 - 19.
