diff --git a/mc/1.21.10/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java b/mc/1.21.10/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
index eccac53e..755c6708 100644
--- a/mc/1.21.10/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
+++ b/mc/1.21.10/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
@@ -37,6 +37,7 @@ public class MaterialsDataGenerator implements IDataGenerator {
         // Base speeds for each tool type
         put("wooden", 2.0f);
         put("stone", 4.0f);
+        put("copper", 5.0f);
         put("iron", 6.0f);
         put("diamond", 8.0f);
         put("netherite", 9.0f);
@@ -173,7 +174,7 @@ public JsonElement generateDataJson() {
 
                                         Map<Item, Float> materialSpeeds = materialMiningSpeeds.computeIfAbsent(materialName, k -> new LinkedHashMap<>());
                                         float baseSpeed = getToolSpeed(item);
-                                        materialSpeeds.put(item, baseSpeed);
+                                        materialSpeeds.putIfAbsent(item, baseSpeed);
                                     }
                                 }
                         );
diff --git a/mc/1.21.11/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java b/mc/1.21.11/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
index eccac53e..755c6708 100644
--- a/mc/1.21.11/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
+++ b/mc/1.21.11/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
@@ -37,6 +37,7 @@ public class MaterialsDataGenerator implements IDataGenerator {
         // Base speeds for each tool type
         put("wooden", 2.0f);
         put("stone", 4.0f);
+        put("copper", 5.0f);
         put("iron", 6.0f);
         put("diamond", 8.0f);
         put("netherite", 9.0f);
@@ -173,7 +174,7 @@ public JsonElement generateDataJson() {
 
                                         Map<Item, Float> materialSpeeds = materialMiningSpeeds.computeIfAbsent(materialName, k -> new LinkedHashMap<>());
                                         float baseSpeed = getToolSpeed(item);
-                                        materialSpeeds.put(item, baseSpeed);
+                                        materialSpeeds.putIfAbsent(item, baseSpeed);
                                     }
                                 }
                         );
diff --git a/mc/1.21.5/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java b/mc/1.21.5/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
index eccac53e..462dec64 100644
--- a/mc/1.21.5/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
+++ b/mc/1.21.5/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
@@ -173,7 +173,7 @@ public JsonElement generateDataJson() {
 
                                         Map<Item, Float> materialSpeeds = materialMiningSpeeds.computeIfAbsent(materialName, k -> new LinkedHashMap<>());
                                         float baseSpeed = getToolSpeed(item);
-                                        materialSpeeds.put(item, baseSpeed);
+                                        materialSpeeds.putIfAbsent(item, baseSpeed);
                                     }
                                 }
                         );
diff --git a/mc/1.21.6/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java b/mc/1.21.6/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
index eccac53e..462dec64 100644
--- a/mc/1.21.6/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
+++ b/mc/1.21.6/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
@@ -173,7 +173,7 @@ public JsonElement generateDataJson() {
 
                                         Map<Item, Float> materialSpeeds = materialMiningSpeeds.computeIfAbsent(materialName, k -> new LinkedHashMap<>());
                                         float baseSpeed = getToolSpeed(item);
-                                        materialSpeeds.put(item, baseSpeed);
+                                        materialSpeeds.putIfAbsent(item, baseSpeed);
                                     }
                                 }
                         );
diff --git a/mc/1.21.7/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java b/mc/1.21.7/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
index eccac53e..462dec64 100644
--- a/mc/1.21.7/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
+++ b/mc/1.21.7/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
@@ -173,7 +173,7 @@ public JsonElement generateDataJson() {
 
                                         Map<Item, Float> materialSpeeds = materialMiningSpeeds.computeIfAbsent(materialName, k -> new LinkedHashMap<>());
                                         float baseSpeed = getToolSpeed(item);
-                                        materialSpeeds.put(item, baseSpeed);
+                                        materialSpeeds.putIfAbsent(item, baseSpeed);
                                     }
                                 }
                         );
diff --git a/mc/1.21.8/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java b/mc/1.21.8/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
index eccac53e..462dec64 100644
--- a/mc/1.21.8/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
+++ b/mc/1.21.8/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
@@ -173,7 +173,7 @@ public JsonElement generateDataJson() {
 
                                         Map<Item, Float> materialSpeeds = materialMiningSpeeds.computeIfAbsent(materialName, k -> new LinkedHashMap<>());
                                         float baseSpeed = getToolSpeed(item);
-                                        materialSpeeds.put(item, baseSpeed);
+                                        materialSpeeds.putIfAbsent(item, baseSpeed);
                                     }
                                 }
                         );
diff --git a/mc/1.21.9/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java b/mc/1.21.9/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
index eccac53e..755c6708 100644
--- a/mc/1.21.9/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
+++ b/mc/1.21.9/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
@@ -37,6 +37,7 @@ public class MaterialsDataGenerator implements IDataGenerator {
         // Base speeds for each tool type
         put("wooden", 2.0f);
         put("stone", 4.0f);
+        put("copper", 5.0f);
         put("iron", 6.0f);
         put("diamond", 8.0f);
         put("netherite", 9.0f);
@@ -173,7 +174,7 @@ public JsonElement generateDataJson() {
 
                                         Map<Item, Float> materialSpeeds = materialMiningSpeeds.computeIfAbsent(materialName, k -> new LinkedHashMap<>());
                                         float baseSpeed = getToolSpeed(item);
-                                        materialSpeeds.put(item, baseSpeed);
+                                        materialSpeeds.putIfAbsent(item, baseSpeed);
                                     }
                                 }
                         );
diff --git a/mc/26.1/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java b/mc/26.1/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
index eccac53e..755c6708 100644
--- a/mc/26.1/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
+++ b/mc/26.1/src/main/java/dev/u9g/minecraftdatagenerator/generators/MaterialsDataGenerator.java
@@ -37,6 +37,7 @@ public class MaterialsDataGenerator implements IDataGenerator {
         // Base speeds for each tool type
         put("wooden", 2.0f);
         put("stone", 4.0f);
+        put("copper", 5.0f);
         put("iron", 6.0f);
         put("diamond", 8.0f);
         put("netherite", 9.0f);
@@ -173,7 +174,7 @@ public JsonElement generateDataJson() {
 
                                         Map<Item, Float> materialSpeeds = materialMiningSpeeds.computeIfAbsent(materialName, k -> new LinkedHashMap<>());
                                         float baseSpeed = getToolSpeed(item);
-                                        materialSpeeds.put(item, baseSpeed);
+                                        materialSpeeds.putIfAbsent(item, baseSpeed);
                                     }
                                 }
                         );